Mybatis常用分页插件实现快速分页处理技巧_Java教程-查字典教程网
Mybatis常用分页插件实现快速分页处理技巧
Mybatis常用分页插件实现快速分页处理技巧
发布时间:2016-12-28 来源:查字典编辑
摘要:在未分享整个查询分页的执行代码之前,先了解一下执行流程。1.总体上是利用mybatis的插件拦截器,在sql执行之前拦截,为查询语句加上li...

在未分享整个查询分页的执行代码之前,先了解一下执行流程。

1.总体上是利用mybatis的插件拦截器,在sql执行之前拦截,为查询语句加上limit X X

2.用一个Page对象,贯穿整个执行流程,这个Page对象需要用Java编写前端分页组件

3.用一套比较完整的三层entity,dao,service支持这个分页架构

4.这个分页用到的一些辅助类

注:分享的内容较多,这边的话我就不把需要的jar一一列举,大家使用这个分页功能的时候缺少什么就去晚上找什么jar包即可,尽可能用maven包导入因为maven能减少版本冲突等比较好的优势。

我只能说尽可能让大家快速使用这个比较好用的分页功能,如果讲得不明白,欢迎加我QQ一起探讨1063150576,。莫喷哈!还有就是文章篇幅可能会比较大,不过花点时间,把它看完并实践一下一定会收获良多。

第一步:既然主题是围绕怎么进行分页的,我们就从mybatis入手,首先,我们把mybatis相关的两个比较重要的配置文件拿出来做简要的理解,一个是mybatis-config.xml,另外一个是实体所对应的mapper配置文件,我会在配置文件上写好注释,大家一看就会明白。

mybatis-config.xml

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <> <settings> <> <setting name="cacheEnabled" value="false"/> <> <setting name="lazyLoadingEnabled" value="true"/> <> <setting name="aggressiveLazyLoading" value="true"/> <> <setting name="multipleResultSetsEnabled" value="true"/> <> <setting name="useColumnLabel" value="true"/> <> <setting name="useGeneratedKeys" value="false"/> <> <setting name="autoMappingBehavior" value="PARTIAL"/> <> <setting name="defaultExecutorType" value="SIMPLE"/> <> <setting name="mapUnderscoreToCamelCase" value="true"/> <> <setting name="localCacheScope" value="SESSION"/> <> <setting name="jdbcTypeForNull" value="NULL"/> <setting name="logPrefix" value="dao."/> </settings> <> <typeAliases> <typeAlias type="com.store.base.model.StoreUser" alias="User"></typeAlias> <typeAlias type="com.store.base.secondmodel.pratice.model.Product" alias="Product"></typeAlias> <typeAlias type="com.store.base.secondmodel.base.Page" alias="Page"></typeAlias> </typeAliases> <> <plugins> <plugin interceptor="com.store.base.secondmodel.base.pageinterceptor.PaginationInterceptor" /> </plugins> </configuration>

一个ProductMapper.xml作为测试对象,这个mapper文件就简单配置一个需要用到的查询语句

<"1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="com.store.base.secondmodel.pratice.dao.ProductDao" > <sql id="baseColumns" > id, product_name as productName, product_no as productNo, price as price </sql> <select id="findList" resultType="com.store.base.secondmodel.pratice.model.Product"> select <include refid="baseColumns"/> from t_store_product </select> </mapper>

第二步:接下去主要针对这个分页拦截器进行深入分析学习,主要有以下几个类和其对应接口

(1)BaseInterceptor 拦截器基础类

(2)PaginationInterceptor 我们要使用的分页插件类,继承上面基础类

(3)SQLHelper 主要是用来提前执行count语句,还有就是获取整个完整的分页语句

(4)Dialect,MysqlDialect,主要用来数据库是否支持limit语句,然后封装完整limit语句

以下是这几个类的分享展示

BaseInterceptor.java

package com.store.base.secondmodel.base.pageinterceptor; import java.io.Serializable; import java.util.Properties; import org.apache.ibatis.logging.Log; import org.apache.ibatis.logging.LogFactory; import org.apache.ibatis.plugin.Interceptor; import com.store.base.secondmodel.base.Global; import com.store.base.secondmodel.base.Page; import com.store.base.secondmodel.base.dialect.Dialect; import com.store.base.secondmodel.base.dialect.MySQLDialect; import com.store.base.util.Reflections; /** * Mybatis分页拦截器基类 * @author yiyong_wu * */ public abstract class BaseInterceptor implements Interceptor, Serializable { private static final long serialVersionUID = 1L; protected static final String PAGE = "page"; protected static final String DELEGATE = "delegate"; protected static final String MAPPED_STATEMENT = "mappedStatement"; protected Log log = LogFactory.getLog(this.getClass()); protected Dialect DIALECT; /** * 对参数进行转换和检查 * @param parameterObject 参数对象 * @param page 分页对象 * @return 分页对象 * @throws NoSuchFieldException 无法找到参数 */ @SuppressWarnings("unchecked") protected static Page<Object> convertParameter(Object parameterObject, Page<Object> page) { try{ if (parameterObject instanceof Page) { return (Page<Object>) parameterObject; } else { return (Page<Object>)Reflections.getFieldValue(parameterObject, PAGE); } }catch (Exception e) { return null; } } /** * 设置属性,支持自定义方言类和制定数据库的方式 * <code>dialectClass</code>,自定义方言类。可以不配置这项 * <ode>dbms</ode> 数据库类型,插件支持的数据库 * <code>sqlPattern</code> 需要拦截的SQL ID * @param p 属性 */ protected void initProperties(Properties p) { Dialect dialect = null; String dbType = Global.getConfig("jdbc.type"); if("mysql".equals(dbType)){ dialect = new MySQLDialect(); } if (dialect == null) { throw new RuntimeException("mybatis dialect error."); } DIALECT = dialect; } }

PaginationInterceptor.java

package com.store.base.secondmodel.base.pageinterceptor; import java.util.Properties; import org.apache.ibatis.executor.Executor; import org.apache.ibatis.mapping.BoundSql; import org.apache.ibatis.mapping.MappedStatement; import org.apache.ibatis.mapping.SqlSource; import org.apache.ibatis.plugin.Intercepts; import org.apache.ibatis.plugin.Invocation; import org.apache.ibatis.plugin.Plugin; import org.apache.ibatis.plugin.Signature; import org.apache.ibatis.reflection.MetaObject; import org.apache.ibatis.session.ResultHandler; import org.apache.ibatis.session.RowBounds; import com.store.base.secondmodel.base.Page; import com.store.base.secondmodel.base.util.StringUtils; import com.store.base.util.Reflections; /** * 数据库分页插件,只拦截查询语句. * @author yiyong_wu * */ @Intercepts({ @Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class }) }) public class PaginationInterceptor extends BaseInterceptor { private static final long serialVersionUID = 1L; @Override public Object intercept(Invocation invocation) throws Throwable { final MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0]; Object parameter = invocation.getArgs()[1]; BoundSql boundSql = mappedStatement.getBoundSql(parameter); Object parameterObject = boundSql.getParameterObject(); // 获取分页参数对象 Page<Object> page = null; if (parameterObject != null) { page = convertParameter(parameterObject, page); } // 如果设置了分页对象,则进行分页 if (page != null && page.getPageSize() != -1) { if (StringUtils.isBlank(boundSql.getSql())) { return null; } String originalSql = boundSql.getSql().trim(); // 得到总记录数 page.setCount(SQLHelper.getCount(originalSql, null,mappedStatement, parameterObject, boundSql, log)); // 分页查询 本地化对象 修改数据库注意修改实现 String pageSql = SQLHelper.generatePageSql(originalSql, page,DIALECT); invocation.getArgs()[2] = new RowBounds(RowBounds.NO_ROW_OFFSET,RowBounds.NO_ROW_LIMIT); BoundSql newBoundSql = new BoundSql( mappedStatement.getConfiguration(), pageSql, boundSql.getParameterMappings(), boundSql.getParameterObject()); // 解决MyBatis 分页foreach 参数失效 start if (Reflections.getFieldValue(boundSql, "metaParameters") != null) { MetaObject mo = (MetaObject) Reflections.getFieldValue( boundSql, "metaParameters"); Reflections.setFieldValue(newBoundSql, "metaParameters", mo); } // 解决MyBatis 分页foreach 参数失效 end MappedStatement newMs = copyFromMappedStatement(mappedStatement,new BoundSqlSqlSource(newBoundSql)); invocation.getArgs()[0] = newMs; } return invocation.proceed(); } @Override public Object plugin(Object target) { return Plugin.wrap(target, this); } @Override public void setProperties(Properties properties) { super.initProperties(properties); } private MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource) { MappedStatement.Builder builder = new MappedStatement.Builder( ms.getConfiguration(), ms.getId(), newSqlSource, ms.getSqlCommandType()); builder.resource(ms.getResource()); builder.fetchSize(ms.getFetchSize()); builder.statementType(ms.getStatementType()); builder.keyGenerator(ms.getKeyGenerator()); if (ms.getKeyProperties() != null) { for (String keyProperty : ms.getKeyProperties()) { builder.keyProperty(keyProperty); } } builder.timeout(ms.getTimeout()); builder.parameterMap(ms.getParameterMap()); builder.resultMaps(ms.getResultMaps()); builder.cache(ms.getCache()); return builder.build(); } public static class BoundSqlSqlSource implements SqlSource { BoundSql boundSql; public BoundSqlSqlSource(BoundSql boundSql) { this.boundSql = boundSql; } @Override public BoundSql getBoundSql(Object parameterObject) { return boundSql; } } }

SQLHelper.java

package com.store.base.secondmodel.base.pageinterceptor; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.ibatis.executor.ErrorContext; import org.apache.ibatis.executor.ExecutorException; import org.apache.ibatis.logging.Log; import org.apache.ibatis.mapping.BoundSql; import org.apache.ibatis.mapping.MappedStatement; import org.apache.ibatis.mapping.ParameterMapping; import org.apache.ibatis.mapping.ParameterMode; import org.apache.ibatis.reflection.MetaObject; import org.apache.ibatis.reflection.property.PropertyTokenizer; import org.apache.ibatis.scripting.xmltags.ForEachSqlNode; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.type.TypeHandler; import org.apache.ibatis.type.TypeHandlerRegistry; import com.store.base.secondmodel.base.Global; import com.store.base.secondmodel.base.Page; import com.store.base.secondmodel.base.dialect.Dialect; import com.store.base.secondmodel.base.util.StringUtils; import com.store.base.util.Reflections; /** * SQL工具类 * @author yiyong_wu * */ public class SQLHelper { /** * 默认私有构造函数 */ private SQLHelper() { } /** * 对SQL参数(?)设值,参考org.apache.ibatis.executor.parameter.DefaultParameterHandler * * @param ps 表示预编译的 SQL 语句的对象。 * @param mappedStatement MappedStatement * @param boundSql SQL * @param parameterObject 参数对象 * @throws java.sql.SQLException 数据库异常 */ @SuppressWarnings("unchecked") public static void setParameters(PreparedStatement ps, MappedStatement mappedStatement, BoundSql boundSql, Object parameterObject) throws SQLException { ErrorContext.instance().activity("setting parameters").object(mappedStatement.getParameterMap().getId()); List<ParameterMapping> parameterMappings = boundSql.getParameterMappings(); if (parameterMappings != null) { Configuration configuration = mappedStatement.getConfiguration(); TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry(); MetaObject metaObject = parameterObject == null ? null : configuration.newMetaObject(parameterObject); for (int i = 0; i < parameterMappings.size(); i++) { ParameterMapping parameterMapping = parameterMappings.get(i); if (parameterMapping.getMode() != ParameterMode.OUT) { Object value; String propertyName = parameterMapping.getProperty(); PropertyTokenizer prop = new PropertyTokenizer(propertyName); if (parameterObject == null) { value = null; } else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) { value = parameterObject; } else if (boundSql.hasAdditionalParameter(propertyName)) { value = boundSql.getAdditionalParameter(propertyName); } else if (propertyName.startsWith(ForEachSqlNode.ITEM_PREFIX) && boundSql.hasAdditionalParameter(prop.getName())) { value = boundSql.getAdditionalParameter(prop.getName()); if (value != null) { value = configuration.newMetaObject(value).getValue(propertyName.substring(prop.getName().length())); } } else { value = metaObject == null ? null : metaObject.getValue(propertyName); } @SuppressWarnings("rawtypes") TypeHandler typeHandler = parameterMapping.getTypeHandler(); if (typeHandler == null) { throw new ExecutorException("There was no TypeHandler found for parameter " + propertyName + " of statement " + mappedStatement.getId()); } typeHandler.setParameter(ps, i + 1, value, parameterMapping.getJdbcType()); } } } } /** * 查询总纪录数 * @param sql SQL语句 * @param connection 数据库连接 * @param mappedStatement mapped * @param parameterObject 参数 * @param boundSql boundSql * @return 总记录数 * @throws SQLException sql查询错误 */ public static int getCount(final String sql, final Connection connection, final MappedStatement mappedStatement, final Object parameterObject, final BoundSql boundSql, Log log) throws SQLException { String dbName = Global.getConfig("jdbc.type"); final String countSql; if("oracle".equals(dbName)){ countSql = "select count(1) from (" + sql + ") tmp_count"; }else{ countSql = "select count(1) from (" + removeOrders(sql) + ") tmp_count"; } Connection conn = connection; PreparedStatement ps = null; ResultSet rs = null; try { if (log.isDebugEnabled()) { log.debug("COUNT SQL: " + StringUtils.replaceEach(countSql, new String[]{"n","t"}, new String[]{" "," "})); } if (conn == null){ conn = mappedStatement.getConfiguration().getEnvironment().getDataSource().getConnection(); } ps = conn.prepareStatement(countSql); BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(), countSql, boundSql.getParameterMappings(), parameterObject); //解决MyBatis 分页foreach 参数失效 start if (Reflections.getFieldValue(boundSql, "metaParameters") != null) { MetaObject mo = (MetaObject) Reflections.getFieldValue(boundSql, "metaParameters"); Reflections.setFieldValue(countBS, "metaParameters", mo); } //解决MyBatis 分页foreach 参数失效 end SQLHelper.setParameters(ps, mappedStatement, countBS, parameterObject); rs = ps.executeQuery(); int count = 0; if (rs.next()) { count = rs.getInt(1); } return count; } finally { if (rs != null) { rs.close(); } if (ps != null) { ps.close(); } if (conn != null) { conn.close(); } } } /** * 根据数据库方言,生成特定的分页sql * @param sql Mapper中的Sql语句 * @param page 分页对象 * @param dialect 方言类型 * @return 分页SQL */ public static String generatePageSql(String sql, Page<Object> page, Dialect dialect) { if (dialect.supportsLimit()) { return dialect.getLimitString(sql, page.getFirstResult(), page.getMaxResults()); } else { return sql; } } /** * 去除qlString的select子句。 * @param hql * @return */ @SuppressWarnings("unused") private static String removeSelect(String qlString){ int beginPos = qlString.toLowerCase().indexOf("from"); return qlString.substring(beginPos); } /** * 去除hql的orderBy子句。 * @param hql * @return */ private static String removeOrders(String qlString) { Pattern p = Pattern.compile("orders*by[w|W|s|S]*", Pattern.CASE_INSENSITIVE); Matcher m = p.matcher(qlString); StringBuffer sb = new StringBuffer(); while (m.find()) { m.appendReplacement(sb, ""); } m.appendTail(sb); return sb.toString(); } }

Dialect.java 接口

package com.store.base.secondmodel.base.dialect; /** * 类似hibernate的Dialect,但只精简出分页部分 * @author yiyong_wu * */ public interface Dialect { /** * 数据库本身是否支持分页当前的分页查询方式 * 如果数据库不支持的话,则不进行数据库分页 * * @return true:支持当前的分页查询方式 */ public boolean supportsLimit(); /** * 将sql转换为分页SQL,分别调用分页sql * * @param sql SQL语句 * @param offset 开始条数 * @param limit 每页显示多少纪录条数 * @return 分页查询的sql */ public String getLimitString(String sql, int offset, int limit); }

MySQLDialect.java

package com.store.base.secondmodel.base.dialect; /** * Mysql方言的实现 * @author yiyong_wu * */ public class MySQLDialect implements Dialect { @Override public boolean supportsLimit() { return true; } @Override public String getLimitString(String sql, int offset, int limit) { return getLimitString(sql, offset, Integer.toString(offset),Integer.toString(limit)); } /** * 将sql变成分页sql语句,提供将offset及limit使用占位符号(placeholder)替换. * <pre> * 如mysql * dialect.getLimitString("select * from user", 12, ":offset",0,":limit") 将返回 * select * from user limit :offset,:limit * </pre> * * @param sql 实际SQL语句 * @param offset 分页开始纪录条数 * @param offsetPlaceholder 分页开始纪录条数-占位符号 * @param limitPlaceholder 分页纪录条数占位符号 * @return 包含占位符的分页sql */ public String getLimitString(String sql, int offset, String offsetPlaceholder, String limitPlaceholder) { StringBuilder stringBuilder = new StringBuilder(sql); stringBuilder.append(" limit "); if (offset > 0) { stringBuilder.append(offsetPlaceholder).append(",").append(limitPlaceholder); } else { stringBuilder.append(limitPlaceholder); } return stringBuilder.toString(); } }

差不多到这边已经把整块分页怎么实现的给分享完了,但是我们还有更重要的任务,想要整个东西跑起来,肯定还要有基础工作要做,接下去我们分析整套Page对象以及它所依据的三层架构,还是用product作为实体进行分析。一整套三层架构讲下来,收获肯定又满满的。我们依次从entity->dao->service的顺序讲下来。

首先,针对我们的实体得继承两个抽象实体类BaseEntity 与 DataEntity

BaseEntity.java 主要放置Page成员变量,继承它后就可以每个实体都拥有这个成员变量

package com.store.base.secondmodel.base; import java.io.Serializable; import java.util.Map; import javax.xml.bind.annotation.XmlTransient; import org.apache.commons.lang3.StringUtils; import org.apache.commons.lang3.builder.ReflectionToStringBuilder; import com.fasterxml.jackson.annotation.JsonIgnore; import com.google.common.collect.Maps; import com.store.base.model.StoreUser; /** * 最顶层的Entity * @author yiyong_wu * * @param <T> */ public abstract class BaseEntity<T> implements Serializable { private static final long serialVersionUID = 1L; /** * 删除标记(0:正常;1:删除;2:审核;) */ public static final String DEL_FLAG_NORMAL = "0"; public static final String DEL_FLAG_DELETE = "1"; public static final String DEL_FLAG_AUDIT = "2"; /** * 实体编号(唯一标识) */ protected String id; /** * 当前用户 */ protected StoreUser currentUser; /** * 当前实体分页对象 */ protected Page<T> page; /** * 自定义SQL(SQL标识,SQL内容) */ private Map<String, String> sqlMap; public BaseEntity() { } public BaseEntity(String id) { this(); this.id = id; } public String getId() { return id; } public void setId(String id) { this.id = id; } /** * 这个主要针对shiro执行插入更新的时候会调用,获取当前的用户 * @return */ @JsonIgnore @XmlTransient public StoreUser getCurrentUser() { if(currentUser == null){ // currentUser = UserUtils.getUser(); } return currentUser; } public void setCurrentUser(StoreUser currentUser) { this.currentUser = currentUser; } @JsonIgnore @XmlTransient public Page<T> getPage() { if (page == null){ page = new Page<>(); } return page; } public Page<T> setPage(Page<T> page) { this.page = page; return page; } @JsonIgnore @XmlTransient public Map<String, String> getSqlMap() { if (sqlMap == null){ sqlMap = Maps.newHashMap(); } return sqlMap; } public void setSqlMap(Map<String, String> sqlMap) { this.sqlMap = sqlMap; } /** * 插入之前执行方法,子类实现 */ public abstract void preInsert(); /** * 更新之前执行方法,子类实现 */ public abstract void preUpdate(); /** * 是否是新记录(默认:false),调用setIsNewRecord()设置新记录,使用自定义ID。 * 设置为true后强制执行插入语句,ID不会自动生成,需从手动传入。 * @return */ public boolean getIsNewRecord() { return StringUtils.isBlank(getId()); } /** * 全局变量对象 */ @JsonIgnore public Global getGlobal() { return Global.getInstance(); } /** * 获取数据库名称 */ @JsonIgnore public String getDbName(){ return Global.getConfig("jdbc.type"); } @Override public String toString() { return ReflectionToStringBuilder.toString(this); } }

DataEntity.java,主要存储更新删除时间,创建用户,更新用户,逻辑删除标志等

package com.store.base.secondmodel.base; import java.util.Date; import org.hibernate.validator.constraints.Length; import com.fasterxml.jackson.annotation.JsonFormat; import com.fasterxml.jackson.annotation.JsonIgnore; import com.store.base.model.StoreUser; /** * 数据Entity * @author yiyong_wu * * @param <T> */ public abstract class DataEntity<T> extends BaseEntity<T> { private static final long serialVersionUID = 1L; protected StoreUser createBy; // 创建者 protected Date createDate; // 创建日期 protected StoreUser updateBy; // 更新者 protected Date updateDate; // 更新日期 protected String delFlag; // 删除标记(0:正常;1:删除;2:审核) public DataEntity() { super(); this.delFlag = DEL_FLAG_NORMAL; } public DataEntity(String id) { super(id); } /** * 插入之前执行方法,需要手动调用 */ @Override public void preInsert() { // 不限制ID为UUID,调用setIsNewRecord()使用自定义ID // User user = UserUtils.getUser(); // if (StringUtils.isNotBlank(user.getId())) { // this.updateBy = user; // this.createBy = user; // } this.updateDate = new Date(); this.createDate = this.updateDate; } /** * 更新之前执行方法,需要手动调用 */ @Override public void preUpdate() { // User user = UserUtils.getUser(); // if (StringUtils.isNotBlank(user.getId())) { // this.updateBy = user; // } this.updateDate = new Date(); } // @JsonIgnore public StoreUser getCreateBy() { return createBy; } public void setCreateBy(StoreUser createBy) { this.createBy = createBy; } @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss") public Date getCreateDate() { return createDate; } public void setCreateDate(Date createDate) { this.createDate = createDate; } // @JsonIgnore public StoreUser getUpdateBy() { return updateBy; } public void setUpdateBy(StoreUser updateBy) { this.updateBy = updateBy; } @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss") public Date getUpdateDate() { return updateDate; } public void setUpdateDate(Date updateDate) { this.updateDate = updateDate; } @JsonIgnore @Length(min = 1, max = 1) public String getDelFlag() { return delFlag; } public void setDelFlag(String delFlag) { this.delFlag = delFlag; } }

Product.java 产品类

package com.store.base.secondmodel.pratice.model; import com.store.base.secondmodel.base.DataEntity; /** *产品基础类 *2016年10月11日 *yiyong_wu */ public class Product extends DataEntity<Product>{ private static final long serialVersionUID = 1L; private String productName; private float price; private String productNo; public String getProductName() { return productName; } public void setProductName(String productName) { this.productName = productName; } public float getPrice() { return price; } public void setPrice(float price) { this.price = price; } public String getProductNo() { return productNo; } public void setProductNo(String productNo) { this.productNo = productNo; } }

怎么样,是不是看到很复杂的一个实体继承连关系,不过这有什么,越复杂就会越完整。接下来我就看看dao层,同样是三层,准备好接受洗礼吧

BaseDao.java 预留接口

package com.store.base.secondmodel.base; /** * 最顶层的DAO接口 * @author yiyong_wu * */ public interface BaseDao { } CrudDao.java 针对增删改查的一个dao接口层 [java] view plain copy print?在CODE上查看代码片派生到我的代码片 package com.store.base.secondmodel.base; import java.util.List; /** * 定义增删改查的DAO接口 * @author yiyong_wu * * @param <T> */ public interface CrudDao<T> extends BaseDao { /** * 获取单条数据 * @param id * @return */ public T get(String id); /** * 获取单条数据 * @param entity * @return */ public T get(T entity); /** * 查询数据列表,如果需要分页,请设置分页对象,如:entity.setPage(new Page<T>()); * @param entity * @return */ public List<T> findList(T entity); /** * 查询所有数据列表 * @param entity * @return */ public List<T> findAllList(T entity); /** * 查询所有数据列表 * @see public List<T> findAllList(T entity) * @return public List<T> findAllList(); */ /** * 插入数据 * @param entity * @return */ public int insert(T entity); /** * 更新数据 * @param entity * @return */ public int update(T entity); /** * 删除数据(一般为逻辑删除,更新del_flag字段为1) * @param id * @see public int delete(T entity) * @return */ public int delete(String id); /** * 删除数据(一般为逻辑删除,更新del_flag字段为1) * @param entity * @return */ public int delete(T entity); }

ProductDao.java mybatis对应的接口mapper,同时也是dao实现,这边需要自定一个注解@MyBatisRepository

package com.store.base.secondmodel.pratice.dao; import com.store.base.secondmodel.base.CrudDao; import com.store.base.secondmodel.base.MyBatisRepository; import com.store.base.secondmodel.pratice.model.Product; /** *TODO *2016年10月11日 *yiyong_wu */ @MyBatisRepository public interface ProductDao extends CrudDao<Product>{ }

自定义注解MyBatisRepository.java,跟自定义注解相关,这里就不做过多的解读,网上资料一堆

package com.store.base.secondmodel.base; import java.lang.annotation.Documented; import java.lang.annotation.Retention; import java.lang.annotation.Target; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.ElementType; import org.springframework.stereotype.Component; /** * 标识MyBatis的DAO,方便{@link org.mybatis.spring.mapper.MapperScannerConfigurer}的扫描。 * * 请注意要在spring的配置文件中配置扫描该注解类的配置 * *<bean id="mapperScannerConfigurer"> *<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> *<property name="basePackage" value="com.store.base.secondmodel" /> *<property name="annotationClass" value="com.store.base.secondmodel.base.MyBatisRepository" /> *</bean> * @author yiyong_wu * */ @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.TYPE) @Documented @Component public @interface MyBatisRepository { String value() default ""; }

注意:跟ProductDao.java联系比较大的是ProductMapper.xml文件,大家可以看到上面那个配置文件的namespace是指向这个dao的路径的。

接下来我们就进入最后的service分析了,一样还是三层继承

BaseService.java

package com.store.base.secondmodel.base; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.transaction.annotation.Transactional; /** * Service的最顶层父类 * @author yiyong_wu * */ @Transactional(readOnly = true) public abstract class BaseService { //日志记录用的 protected Logger logger = LoggerFactory.getLogger(getClass()); }

CrudService.java 增删改查相关的业务接口实现

package com.store.base.secondmodel.base; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.transaction.annotation.Transactional; /** * 增删改查Service基类 * @author yiyong_wu * * @param <D> * @param <T> */ public abstract class CrudService<D extends CrudDao<T>, T extends DataEntity<T>> extends BaseService { /** * 持久层对象 */ @Autowired protected D dao; /** * 获取单条数据 * @param id * @return */ public T get(String id) { return dao.get(id); } /** * 获取单条数据 * @param entity * @return */ public T get(T entity) { return dao.get(entity); } /** * 查询列表数据 * @param entity * @return */ public List<T> findList(T entity) { return dao.findList(entity); } /** * 查询分页数据 * @param page 分页对象 * @param entity * @return */ public Page<T> findPage(Page<T> page, T entity) { entity.setPage(page); page.setList(dao.findList(entity)); return page; } /** * 保存数据(插入或更新) * @param entity */ @Transactional(readOnly = false) public void save(T entity) { if (entity.getIsNewRecord()){ entity.preInsert(); dao.insert(entity); }else{ entity.preUpdate(); dao.update(entity); } } /** * 删除数据 * @param entity */ @Transactional(readOnly = false) public void delete(T entity) { dao.delete(entity); } }

ProductService.java,去继承CrudService接口,注意起注入dao和实体类型的一种模式

package com.store.base.secondmodel.pratice.service; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import com.store.base.secondmodel.base.CrudService; import com.store.base.secondmodel.pratice.dao.ProductDao; import com.store.base.secondmodel.pratice.model.Product; /** *TODO *2016年10月11日 *yiyong_wu */ @Service @Transactional(readOnly = true) public class ProductService extends CrudService<ProductDao,Product>{ }

我想看到这里的同志已经很不耐烦了。但是如果你错过接下去的一段,基本上刚才看的就快等于白看了,革命的胜利就在后半段,因为整个分页功能围绕的就是一个Page对象,重磅内容终于要出来了,当你把Page对象填充到刚才那个BaseEntity上的时候,你会发现一切就完整起来了,废话不多说,Page对象如下

package com.store.base.secondmodel.base; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import java.util.regex.Pattern; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.fasterxml.jackson.annotation.JsonIgnore; import com.store.base.secondmodel.base.util.CookieUtils; import com.store.base.secondmodel.base.util.StringUtils; /** * 分页类 * @author yiyong_wu * * @param <T> */ public class Page<T> implements Serializable{ private static final long serialVersionUID = 1L; private int pageNo = 1; // 当前页码 private int pageSize = Integer.parseInt(Global.getConfig("page.pageSize")); // 页面大小,设置为“-1”表示不进行分页(分页无效) private long count;// 总记录数,设置为“-1”表示不查询总数 private int first;// 首页索引 private int last;// 尾页索引 private int prev;// 上一页索引 private int next;// 下一页索引 private boolean firstPage;//是否是第一页 private boolean lastPage;//是否是最后一页 private int length = 6;// 显示页面长度 private int slider = 1;// 前后显示页面长度 private List<T> list = new ArrayList<>(); private String orderBy = ""; // 标准查询有效, 实例: updatedate desc, name asc private String funcName = "page"; // 设置点击页码调用的js函数名称,默认为page,在一页有多个分页对象时使用。 private String funcParam = ""; // 函数的附加参数,第三个参数值。 private String message = ""; // 设置提示消息,显示在“共n条”之后 public Page() { this.pageSize = -1; } /** * 构造方法 * @param request 传递 repage 参数,来记住页码 * @param response 用于设置 Cookie,记住页码 */ public Page(HttpServletRequest request, HttpServletResponse response){ this(request, response, -2); } /** * 构造方法 * @param request 传递 repage 参数,来记住页码 * @param response 用于设置 Cookie,记住页码 * @param defaultPageSize 默认分页大小,如果传递 -1 则为不分页,返回所有数据 */ public Page(HttpServletRequest request, HttpServletResponse response, int defaultPageSize){ // 设置页码参数(传递repage参数,来记住页码) String no = request.getParameter("pageNo"); if (StringUtils.isNumeric(no)){ CookieUtils.setCookie(response, "pageNo", no); this.setPageNo(Integer.parseInt(no)); }else if (request.getParameter("repage")!=null){ no = CookieUtils.getCookie(request, "pageNo"); if (StringUtils.isNumeric(no)){ this.setPageNo(Integer.parseInt(no)); } } // 设置页面大小参数(传递repage参数,来记住页码大小) String size = request.getParameter("pageSize"); if (StringUtils.isNumeric(size)){ CookieUtils.setCookie(response, "pageSize", size); this.setPageSize(Integer.parseInt(size)); }else if (request.getParameter("repage")!=null){ no = CookieUtils.getCookie(request, "pageSize"); if (StringUtils.isNumeric(size)){ this.setPageSize(Integer.parseInt(size)); } }else if (defaultPageSize != -2){ this.pageSize = defaultPageSize; } // 设置排序参数 String orderBy = request.getParameter("orderBy"); if (StringUtils.isNotBlank(orderBy)){ this.setOrderBy(orderBy); } } /** * 构造方法 * @param pageNo 当前页码 * @param pageSize 分页大小 */ public Page(int pageNo, int pageSize) { this(pageNo, pageSize, 0); } /** * 构造方法 * @param pageNo 当前页码 * @param pageSize 分页大小 * @param count 数据条数 */ public Page(int pageNo, int pageSize, long count) { this(pageNo, pageSize, count, new ArrayList<T>()); } /** * 构造方法 * @param pageNo 当前页码 * @param pageSize 分页大小 * @param count 数据条数 * @param list 本页数据对象列表 */ public Page(int pageNo, int pageSize, long count, List<T> list) { this.setCount(count); this.setPageNo(pageNo); this.pageSize = pageSize; this.list = list; } /** * 初始化参数 */ public void initialize(){ //1 this.first = 1; this.last = (int)(count / (this.pageSize < 1 ? 20 : this.pageSize) + first - 1); if (this.count % this.pageSize != 0 || this.last == 0) { this.last++; } if (this.last < this.first) { this.last = this.first; } if (this.pageNo <= 1) { this.pageNo = this.first; this.firstPage=true; } if (this.pageNo >= this.last) { this.pageNo = this.last; this.lastPage=true; } if (this.pageNo < this.last - 1) { this.next = this.pageNo + 1; } else { this.next = this.last; } if (this.pageNo > 1) { this.prev = this.pageNo - 1; } else { this.prev = this.first; } //2 if (this.pageNo < this.first) {// 如果当前页小于首页 this.pageNo = this.first; } if (this.pageNo > this.last) {// 如果当前页大于尾页 this.pageNo = this.last; } } /** * 默认输出当前分页标签 * <div>${page}</div> */ @Override public String toString() { StringBuilder sb = new StringBuilder(); if (pageNo == first) {// 如果是首页 sb.append("<li><a href="javascript:">« 上一页</a></li>n"); } else { sb.append("<li><a href="javascript:" onclick=""+funcName+"("+prev+","+pageSize+",'"+funcParam+"');">« 上一页</a></li>n"); } int begin = pageNo - (length / 2); if (begin < first) { begin = first; } int end = begin + length - 1; if (end >= last) { end = last; begin = end - length + 1; if (begin < first) { begin = first; } } if (begin > first) { int i = 0; for (i = first; i < first + slider && i < begin; i++) { sb.append("<li><a href="javascript:" onclick=""+funcName+"("+i+","+pageSize+",'"+funcParam+"');">" + (i + 1 - first) + "</a></li>n"); } if (i < begin) { sb.append("<li><a href="javascript:">...</a></li>n"); } } for (int i = begin; i <= end; i++) { if (i == pageNo) { sb.append("<li><a href="javascript:">" + (i + 1 - first) + "</a></li>n"); } else { sb.append("<li><a href="javascript:" onclick=""+funcName+"("+i+","+pageSize+",'"+funcParam+"');">" + (i + 1 - first) + "</a></li>n"); } } if (last - end > slider) { sb.append("<li><a href="javascript:">...</a></li>n"); end = last - slider; } for (int i = end + 1; i <= last; i++) { sb.append("<li><a href="javascript:" onclick=""+funcName+"("+i+","+pageSize+",'"+funcParam+"');">" + (i + 1 - first) + "</a></li>n"); } if (pageNo == last) { sb.append("<li><a href="javascript:">下一页 »</a></li>n"); } else { sb.append("<li><a href="javascript:" onclick=""+funcName+"("+next+","+pageSize+",'"+funcParam+"');">" + "下一页 »</a></li>n"); } return sb.toString(); } /** * 获取分页HTML代码 * @return */ public String getHtml(){ return toString(); } /** * 获取设置总数 * @return */ public long getCount() { return count; } /** * 设置数据总数 * @param count */ public void setCount(long count) { this.count = count; if (pageSize >= count){ pageNo = 1; } } /** * 获取当前页码 * @return */ public int getPageNo() { return pageNo; } /** * 设置当前页码 * @param pageNo */ public void setPageNo(int pageNo) { this.pageNo = pageNo; } /** * 获取页面大小 * @return */ public int getPageSize() { return pageSize; } /** * 设置页面大小(最大500)// > 500 ? 500 : pageSize; * @param pageSize */ public void setPageSize(int pageSize) { this.pageSize = pageSize <= 0 ? 10 : pageSize; } /** * 首页索引 * @return */ @JsonIgnore public int getFirst() { return first; } /** * 尾页索引 * @return */ @JsonIgnore public int getLast() { return last; } /** * 获取页面总数 * @return getLast(); */ @JsonIgnore public int getTotalPage() { return getLast(); } /** * 是否为第一页 * @return */ @JsonIgnore public boolean isFirstPage() { return firstPage; } /** * 是否为最后一页 * @return */ @JsonIgnore public boolean isLastPage() { return lastPage; } /** * 上一页索引值 * @return */ @JsonIgnore public int getPrev() { if (isFirstPage()) { return pageNo; } else { return pageNo - 1; } } /** * 下一页索引值 * @return */ @JsonIgnore public int getNext() { if (isLastPage()) { return pageNo; } else { return pageNo + 1; } } /** * 获取本页数据对象列表 * @return List<T> */ public List<T> getList() { return list; } /** * 设置本页数据对象列表 * @param list */ public Page<T> setList(List<T> list) { this.list = list; initialize(); return this; } /** * 获取查询排序字符串 * @return */ @JsonIgnore public String getOrderBy() { // SQL过滤,防止注入 String reg = "(?:')|(?:--)|(/*(?:.|[nr])*"(b(select|update|and|or|delete|insert|trancate|char|into|substr|ascii|declare|exec|count|master|into|drop|execute)b)"; Pattern sqlPattern = Pattern.compile(reg, Pattern.CASE_INSENSITIVE); if (sqlPattern.matcher(orderBy).find()) { return ""; } return orderBy; } /** * 设置查询排序,标准查询有效, 实例: updatedate desc, name asc */ public void setOrderBy(String orderBy) { this.orderBy = orderBy; } /** * 获取点击页码调用的js函数名称 * function ${page.funcName}(pageNo){location="${ctx}/list-${category.id}${urlSuffix}"+i;} * @return */ @JsonIgnore public String getFuncName() { return funcName; } /** * 设置点击页码调用的js函数名称,默认为page,在一页有多个分页对象时使用。 * @param funcName 默认为page */ public void setFuncName(String funcName) { this.funcName = funcName; } /** * 获取分页函数的附加参数 * @return */ @JsonIgnore public String getFuncParam() { return funcParam; } /** * 设置分页函数的附加参数 * @return */ public void setFuncParam(String funcParam) { this.funcParam = funcParam; } /** * 设置提示消息,显示在“共n条”之后 * @param message */ public void setMessage(String message) { this.message = message; } /** * 分页是否有效 * @return this.pageSize==-1 */ @JsonIgnore public boolean isDisabled() { return this.pageSize==-1; } /** * 是否进行总数统计 * @return this.count==-1 */ @JsonIgnore public boolean isNotCount() { return this.count==-1; } /** * 获取 Hibernate FirstResult */ public int getFirstResult(){ int firstResult = (getPageNo() - 1) * getPageSize(); if (firstResult >= getCount()) { firstResult = 0; } return firstResult; } /** * 获取 Hibernate MaxResults */ public int getMaxResults(){ return getPageSize(); } }

看完这个Page对象应该稍微有点感觉了吧,然后我在胡乱贴一些相关用到的工具类吧,工具类的话我只稍微提一下,具体大家可以弄到自己的代码上好好解读。

PropertiesLoader.java 用来获取resource文件夹下的常量配置文件

package com.store.base.secondmodel.base.util; import java.io.IOException; import java.io.InputStream; import java.util.NoSuchElementException; import java.util.Properties; import org.apache.commons.io.IOUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.core.io.DefaultResourceLoader; import org.springframework.core.io.Resource; import org.springframework.core.io.ResourceLoader; /** * Properties文件载入工具类. 可载入多个properties文件, * 相同的属性在最后载入的文件中的值将会覆盖之前的值,但以System的Property优先. * @author yiyong_wu * */ public class PropertiesLoader { private static Logger logger = LoggerFactory.getLogger(PropertiesLoader.class); private static ResourceLoader resourceLoader = new DefaultResourceLoader(); private final Properties properties; public PropertiesLoader(String... resourcesPaths) { properties = loadProperties(resourcesPaths); } public Properties getProperties() { return properties; } /** * 取出Property,但以System的Property优先,取不到返回空字符串. */ private String getValue(String key) { String systemProperty = System.getProperty(key); if (systemProperty != null) { return systemProperty; } if (properties.containsKey(key)) { return properties.getProperty(key); } return ""; } /** * 取出String类型的Property,但以System的Property优先,如果都为Null则抛出异常. */ public String getProperty(String key) { String value = getValue(key); if (value == null) { throw new NoSuchElementException(); } return value; } /** * 取出String类型的Property,但以System的Property优先.如果都为Null则返回Default值. */ public String getProperty(String key, String defaultValue) { String value = getValue(key); return value != null ? value : defaultValue; } /** * 取出Integer类型的Property,但以System的Property优先.如果都为Null或内容错误则抛出异常. */ public Integer getInteger(String key) { String value = getValue(key); if (value == null) { throw new NoSuchElementException(); } return Integer.valueOf(value); } /** * 取出Integer类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容错误则抛出异常 */ public Integer getInteger(String key, Integer defaultValue) { String value = getValue(key); return value != null ? Integer.valueOf(value) : defaultValue; } /** * 取出Double类型的Property,但以System的Property优先.如果都为Null或内容错误则抛出异常. */ public Double getDouble(String key) { String value = getValue(key); if (value == null) { throw new NoSuchElementException(); } return Double.valueOf(value); } /** * 取出Double类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容错误则抛出异常 */ public Double getDouble(String key, Integer defaultValue) { String value = getValue(key); return value != null ? Double.valueOf(value) : defaultValue.doubleValue(); } /** * 取出Boolean类型的Property,但以System的Property优先.如果都为Null抛出异常,如果内容不是true/false则返回false. */ public Boolean getBoolean(String key) { String value = getValue(key); if (value == null) { throw new NoSuchElementException(); } return Boolean.valueOf(value); } /** * 取出Boolean类型的Property,但以System的Property优先.如果都为Null则返回Default值,如果内容不为true/false则返回false. */ public Boolean getBoolean(String key, boolean defaultValue) { String value = getValue(key); return value != null ? Boolean.valueOf(value) : defaultValue; } /** * 载入多个文件, 文件路径使用Spring Resource格式. */ private Properties loadProperties(String... resourcesPaths) { Properties props = new Properties(); for (String location : resourcesPaths) { InputStream is = null; try { Resource resource = resourceLoader.getResource(location); is = resource.getInputStream(); props.load(is); } catch (IOException ex) { logger.error("Could not load properties from path:" + location , ex); } finally { IOUtils.closeQuietly(is); } } return props; } }

Global.java 用来获取全局的一些常量,可以是从配置文件中读取的常量,也可以是定义成final static的常量,获取配置文件的话是调用上面那个类进行获取的。

package com.store.base.secondmodel.base; import java.io.File; import java.io.IOException; import java.util.Map; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.core.io.DefaultResourceLoader; import com.google.common.collect.Maps; import com.store.base.secondmodel.base.util.PropertiesLoader; import com.store.base.secondmodel.base.util.StringUtils; /** * 全局配置类 * @author yiyong_wu * */ public class Global { private static final Logger logger = LoggerFactory.getLogger(Global.class); /** * 当前对象实例 */ private static Global global = new Global(); /** * 保存全局属性值 */ private static Map<String, String> map = Maps.newHashMap(); /** * 属性文件加载对象 */ private static PropertiesLoader loader = new PropertiesLoader("application.properties"); /** * 显示/隐藏 public static final String SHOW = "1"; public static final String HIDE = "0"; /** * 是/否 */ public static final String YES = "1"; public static final String NO = "0"; /** * 状态 上/下 app专用 */ public static final String UPSHVELF = "1"; public static final String DOWNSHVELF = "2"; public static final String SEPARATOR = "/"; /** * 对/错 */ public static final String TRUE = "true"; public static final String FALSE = "false"; /** * 上传文件基础虚拟路径 */ public static final String USERFILES_BASE_URL = "/userfiles/"; /** * 针对富文本编辑器,结尾会产生的空div */ public static final String ENDS = "<p><br></p>"; /** * 默认空的私有构造函数 */ public Global() { //do nothing in this method,just empty } /** * 获取当前对象实例 */ public static Global getInstance() { return global; } /** * 获取配置 */ public static String getConfig(String key) { String value = map.get(key); if (value == null){ value = loader.getProperty(key); map.put(key, value != null ? value : StringUtils.EMPTY); } return value; } /** * 获取URL后缀 */ public static String getUrlSuffix() { return getConfig("urlSuffix"); } /** * 页面获取常量 * @see ${fns:getConst('YES')} */ public static Object getConst(String field) { try { return Global.class.getField(field).get(null); } catch (Exception e) { logger.error("获取常量出错", e); } return null; } /** * 获取工程路径 * @return */ public static String getProjectPath(){ // 如果配置了工程路径,则直接返回,否则自动获取。 String projectPath = Global.getConfig("projectPath"); if (StringUtils.isNotBlank(projectPath)){ return projectPath; } try { File file = new DefaultResourceLoader().getResource("").getFile(); if (file != null){ while(true){ File f = new File(file.getPath() + File.separator + "src" + File.separator + "main"); if (f == null || f.exists()){ break; } if (file.getParentFile() != null){ file = file.getParentFile(); }else{ break; } } projectPath = file.toString(); } } catch (IOException e) { logger.error("加载配置文件失败", e); } return projectPath; } }

CookieUtil.java 从名称就知道是针对获取和存储cookie的一个工具类

package com.store.base.secondmodel.base.util; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.net.URLEncoder; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Cookie工具类 * @author yiyong_wu * */ public class CookieUtils { private static final Logger logger = LoggerFactory.getLogger(CookieUtils.class); /** * 私有构造函数 */ private CookieUtils() { } /** * 设置 Cookie(生成时间为1年) * @param name 名称 * @param value 值 */ public static void setCookie(HttpServletResponse response, String name, String value) { setCookie(response, name, value, 60*60*24*365); } /** * 设置 Cookie * @param name 名称 * @param value 值 * @param maxAge 生存时间(单位秒) * @param uri 路径 */ public static void setCookie(HttpServletResponse response, String name, String value, String path) { setCookie(response, name, value, path, 60*60*24*365); } /** * 设置 Cookie * @param name 名称 * @param value 值 * @param maxAge 生存时间(单位秒) * @param uri 路径 */ public static void setCookie(HttpServletResponse response, String name, String value, int maxAge) { setCookie(response, name, value, "/", maxAge); } /** * 设置 Cookie * @param name 名称 * @param value 值 * @param maxAge 生存时间(单位秒) * @param uri 路径 */ public static void setCookie(HttpServletResponse response, String name, String value, String path, int maxAge) { Cookie cookie = new Cookie(name, null); cookie.setPath(path); cookie.setMaxAge(maxAge); try { cookie.setValue(URLEncoder.encode(value, "utf-8")); } catch (UnsupportedEncodingException e) { logger.error("不支持的编码", e); } response.addCookie(cookie); } /** * 获得指定Cookie的值 * @param name 名称 * @return 值 */ public static String getCookie(HttpServletRequest request, String name) { return getCookie(request, null, name, false); } /** * 获得指定Cookie的值,并删除。 * @param name 名称 * @return 值 */ public static String getCookie(HttpServletRequest request, HttpServletResponse response, String name) { return getCookie(request, response, name, true); } /** * 获得指定Cookie的值 * @param request 请求对象 * @param response 响应对象 * @param name 名字 * @param isRemove 是否移除 * @return 值 */ public static String getCookie(HttpServletRequest request, HttpServletResponse response, String name, boolean isRemove) { String value = null; Cookie[] cookies = request.getCookies(); if(cookies == null) { return value; } for (Cookie cookie : cookies) { if (cookie.getName().equals(name)) { try { value = URLDecoder.decode(cookie.getValue(), "utf-8"); } catch (UnsupportedEncodingException e) { logger.error("不支持的编码", e); } if (isRemove) { cookie.setMaxAge(0); response.addCookie(cookie); } } } return value; } }

SpringContextHolder.java 主要是用来在java代码中获取当前的ApplicationContext,需要在spring配置文件中配置这个bean并且懒加载设置成false;

package com.store.base.secondmodel.base.util; import org.apache.commons.lang3.Validate; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.DisposableBean; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; import org.springframework.context.annotation.Lazy; import org.springframework.stereotype.Service; @Service @Lazy(false) public class SpringContextHolder implements ApplicationContextAware, DisposableBean { private static Logger logger = LoggerFactory.getLogger(SpringContextHolder.class); private static ApplicationContext applicationContext = null; /** * 取得存储在静态变量中的ApplicationContext. */ public static ApplicationContext getApplicationContext() { assertContextInjected(); return applicationContext; } /** * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型. */ @SuppressWarnings("unchecked") public static <T> T getBean(String name) { assertContextInjected(); return (T) applicationContext.getBean(name); } /** * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型. */ public static <T> T getBean(Class<T> requiredType) { assertContextInjected(); return applicationContext.getBean(requiredType); } @Override public void destroy() throws Exception { SpringContextHolder.clearHolder(); } /** * 实现ApplicationContextAware接口, 注入Context到静态变量中. */ @Override public void setApplicationContext(ApplicationContext applicationContext) { logger.debug("注入ApplicationContext到SpringContextHolder:{}", applicationContext); SpringContextHolder.applicationContext = applicationContext; if (SpringContextHolder.applicationContext != null) { logger.info("SpringContextHolder中的ApplicationContext被覆盖, 原有ApplicationContext为:" + SpringContextHolder.applicationContext); } } /** * 清除SpringContextHolder中的ApplicationContext为Null. */ public static void clearHolder() { if (logger.isDebugEnabled()){ logger.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext); } applicationContext = null; } /** * 检查ApplicationContext不为空. */ private static void assertContextInjected() { Validate.validState(applicationContext != null, "applicaitonContext属性未注入, 请在applicationContext.xml中定义SpringContextHolder."); } }

StringUtils.java字符串相关的一个工具类

package com.store.base.secondmodel.base.util; import java.io.UnsupportedEncodingException; import java.util.Locale; import java.util.regex.Matcher; import java.util.regex.Pattern; import javax.servlet.http.HttpServletRequest; import org.apache.commons.lang3.StringEscapeUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import org.springframework.web.servlet.LocaleResolver; import com.store.base.util.Encodes; /** * 字符串帮助类 * @author yiyong_wu * */ public class StringUtils extends org.apache.commons.lang3.StringUtils { private static final char SEPARATOR = '_'; private static final String CHARSET_NAME = "UTF-8"; private static final Logger logger = LoggerFactory.getLogger(StringUtils.class); /** * 转换为字节数组 * @param str * @return */ public static byte[] getBytes(String str){ if (str != null){ try { return str.getBytes(CHARSET_NAME); } catch (UnsupportedEncodingException e) { logger.error("", e); return new byte[0]; } }else{ return new byte[0]; } } /** * 转换为字节数组 * @param str * @return */ public static String toString(byte[] bytes){ try { return new String(bytes, CHARSET_NAME); } catch (UnsupportedEncodingException e) { logger.error("", e); return EMPTY; } } /** * 是否包含字符串 * @param str 验证字符串 * @param strs 字符串组 * @return 包含返回true */ public static boolean inString(String str, String... strs){ if (str != null){ for (String s : strs){ if (str.equals(trim(s))){ return true; } } } return false; } /** * 替换掉HTML标签方法 */ public static String replaceHtml(String html) { if (isBlank(html)){ return ""; } String regEx = "<.+"; Pattern p = Pattern.compile(regEx); Matcher m = p.matcher(html); return m.replaceAll(""); } /** * 替换为手机识别的HTML,去掉样式及属性,保留回车。 * @param html * @return */ public static String replaceMobileHtml(String html){ if (html == null){ return ""; } return html.replaceAll("<([a-z]+?)s+"<$1>"); } /** * 替换为手机识别的HTML,去掉样式及属性,保留回车。 * @param txt * @return */ public static String toHtml(String txt){ if (txt == null){ return ""; } return replace(replace(Encodes.escapeHtml(txt), "n", "<br/>"), "t", " "); } /** * 缩略字符串(不区分中英文字符) * @param str 目标字符串 * @param length 截取长度 * @return */ public static String abbr(String str, int length) { if (str == null) { return ""; } try { StringBuilder sb = new StringBuilder(); int currentLength = 0; for (char c : replaceHtml(StringEscapeUtils.unescapeHtml4(str)).toCharArray()) { currentLength += String.valueOf(c).getBytes("GBK").length; if (currentLength <= length - 3) { sb.append(c); } else { sb.append("..."); break; } } return sb.toString(); } catch (UnsupportedEncodingException e) { logger.error("", e); } return ""; } /** * 转换为Double类型 */ public static Double toDouble(Object val){ if (val == null){ return 0D; } try { return Double.valueOf(trim(val.toString())); } catch (Exception e) { logger.error("", e); return 0D; } } /** * 转换为Float类型 */ public static Float toFloat(Object val){ return toDouble(val).floatValue(); } /** * 转换为Long类型 */ public static Long toLong(Object val){ return toDouble(val).longValue(); } /** * 转换为Integer类型 */ public static Integer toInteger(Object val){ return toLong(val).intValue(); } /** * 获得i18n字符串 */ public static String getMessage(String code, Object[] args) { LocaleResolver localLocaleResolver = SpringContextHolder.getBean(LocaleResolver.class); HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest(); Locale localLocale = localLocaleResolver.resolveLocale(request); return SpringContextHolder.getApplicationContext().getMessage(code, args, localLocale); } /** * 获得用户远程地址 */ public static String getRemoteAddr(HttpServletRequest request){ String remoteAddr = request.getHeader("X-Real-IP"); if (isNotBlank(remoteAddr)) { remoteAddr = request.getHeader("X-Forwarded-For"); } if (isNotBlank(remoteAddr)) { remoteAddr = request.getHeader("Proxy-Client-IP"); } if (isNotBlank(remoteAddr)) { remoteAddr = request.getHeader("WL-Proxy-Client-IP"); } return remoteAddr != null ? remoteAddr : request.getRemoteAddr(); } /** * 驼峰命名法工具 * @return * toCamelCase("hello_world") == "helloWorld" * toCapitalizeCamelCase("hello_world") == "HelloWorld" * toUnderScoreCase("helloWorld") = "hello_world" */ public static String toCamelCase(String s) { String s1 =s; if (s1 == null) { return null; } s1 = s.toLowerCase(); StringBuilder sb = new StringBuilder(s1.length()); boolean upperCase = false; for (int i = 0; i < s1.length(); i++) { char c = s1.charAt(i); if (c == SEPARATOR) { upperCase = true; } else if (upperCase) { sb.append(Character.toUpperCase(c)); upperCase = false; } else { sb.append(c); } } return sb.toString(); } /** * 驼峰命名法工具 * @return * toCamelCase("hello_world") == "helloWorld" * toCapitalizeCamelCase("hello_world") == "HelloWorld" * toUnderScoreCase("helloWorld") = "hello_world" */ public static String toCapitalizeCamelCase(String s) { String s1 = s; if (s1 == null) { return null; } s1 = toCamelCase(s1); return s1.substring(0, 1).toUpperCase() + s1.substring(1); } /** * 驼峰命名法工具 * @return * toCamelCase("hello_world") == "helloWorld" * toCapitalizeCamelCase("hello_world") == "HelloWorld" * toUnderScoreCase("helloWorld") = "hello_world" */ public static String toUnderScoreCase(String s) { if (s == null) { return null; } StringBuilder sb = new StringBuilder(); boolean upperCase = false; for (int i = 0; i < s.length(); i++) { char c = s.charAt(i); boolean nextUpperCase = true; if (i < (s.length() - 1)) { nextUpperCase = Character.isUpperCase(s.charAt(i + 1)); } if ((i > 0) && Character.isUpperCase(c)) { if (!upperCase || !nextUpperCase) { sb.append(SEPARATOR); } upperCase = true; } else { upperCase = false; } sb.append(Character.toLowerCase(c)); } return sb.toString(); } /** * 转换为JS获取对象值,生成三目运算返回结果 * @param objectString 对象串 * 例如:row.user.id * 返回:!row?'':!row.user?'':!row.user.id?'':row.user.id */ public static String jsGetVal(String objectString){ StringBuilder result = new StringBuilder(); StringBuilder val = new StringBuilder(); String[] vals = split(objectString, "."); for (int i=0; i<vals.length; i++){ val.append("." + vals[i]); result.append("!"+(val.substring(1))+""); } result.append(val.substring(1)); return result.toString(); } }

有了上面这些基础的东西,只需要在写一个控制层接口,就可以看到每次返回一个page对象,然后里面封装好了查询对象的列表,并且是按分页得出列表。

package com.store.controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.bind.annotation.RestController; import com.store.base.secondmodel.base.Page; import com.store.base.secondmodel.pratice.model.Product; import com.store.base.secondmodel.pratice.service.ProductService; /** *TODO *2016年10月11日 *yiyong_wu */ @RestController @RequestMapping("/product") public class ProductController { @Autowired private ProductService productService; @ResponseBody @RequestMapping(value="/getPageProduct") public Page<Product> getPageProduct(HttpServletRequest request,HttpServletResponse response){ Page<Product> page = productService.findPage(new Page<Product>(request,response), new Product()); return page; } }

最后在看一下页面怎么使用这个page对象,这样我们就完整地介绍了这个一个分页功能,代码很多,但很完整。

<%@ page contentType="text/html;charset=UTF-8"%> <%@ include file="/WEB-INF/views/include/taglib.jsp"%> <html> <head> <title></title> <meta name="decorator" content="default" /> function page(n, s) { if (n) $("#pageNo").val(n); if (s) $("#pageSize").val(s); $("#searchForm").attr("action", "${ctx}/app/bank/list"); $("#searchForm").submit(); return false; } </script> </head> <body> <form:form id="searchForm" modelAttribute="XXXX" action="${ctx}/XXX" method="post"> <input id="pageNo" name="pageNo" type="hidden" value="${page.pageNo}" /> <input id="pageSize" name="pageSize" type="hidden" value="${page.pageSize}" /> <ul> <li> <label>是否上架:</label> <form:select id="status" path="status"> <form:option value="" label=""/> <form:options items="${fns:getDictList('yes_no_app')}" itemLabel="label" itemValue="value" htmlEscape="false"/> </form:select> </li> <li><input id="btnSubmit" type="submit" value="查询"/> <li></li> </ul> </form:form> <sys:message content="${message}" /> <sys:message content="${message}" /> <table id="contentTable" > <thead> <tr> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> <th>XXXX</th> </tr> </thead> <tbody> <c:forEach items="${page.list}" var="XXXX"> <tr> <td>${XXXX.name}</td> <td><a href="${ctx}/app/bank/form">${XXXX.}</a></td> <td>${XXXX.}</td> <td>${XXXX.}</td> <td>${XXXX.}</td> <td>${fns:getDictLabel(XXXX.isHot, 'yes_no_app', '无')}</td> <td>${XXXX.}</td> <td><c:if test="${XXXX.status==1 }">上架</c:if> <c:if test="${XXXX.status==2 }">下架</c:if> </td> </tr> </c:forEach> </tbody> </table> <div>${page} <li>共${page.count}条</li></div> </body> </html>

到这里就基本上把整个分页功能描述得比较清楚了,希望可以帮助到你们快速解决分页这个问题,当然要在前端显示分页漂亮的话要针对li做一些css样式啥的,最后祝福你可以快速掌握这个分页功能!

以上所述是小编给大家介绍的Mybatis常用分页插件实现快速分页处理技巧,希望对大家有所帮助,如果大家有任何疑问请给我们留言,小编会及时回复大家的。在此也非常感谢大家对查字典教程网的支持!

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