本文和大家一起了解了一下android客户端与服务端是怎样交互的，具体内容如下

1.后台使用简单的servlet，支持GET或POST。这个servlet最终返回给前台一个字符串flag，值是true或false，表示登录是否成功。

servlet使用之前需要配置，主义servlet的servlet-name要和servlet-mapping的servlet-name一致，否则找不到路径

我是在myEclipse上创建的一个web service 项目，然后部署到tomcat服务器上以便android客户端访问

<servlet> <servlet-name>helloWorld</servlet-name> <servlet-class>com.zhongzhong.wap.action.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>helloWorld</servlet-name> <url-pattern>/queryOrder</url-pattern> </servlet-mapping> import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import com.zhongzhong.wap.bean.UserBean; public class HelloServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setContentType(text/html); PrintWriter out = resp.getWriter(); Boolean flag = false; String userName = req.getParameter(un); String password = req.getParameter(pw); if(userName.equals(htp)&&password.equals(123)) { flag = true; } else flag = false; System.out.println(userName:+userName+ password:+password); out.print(flag); out.flush(); out.close(); } }

2.然后我是在安卓的ADT上创建一个安卓项目，建立两个Activity，分别作为登录界面和登录成功界面。

<relativelayout android:layout_height="match_parent" android:layout_width="match_parent" android:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" tools:context=".MainActivity" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"> <textview android:id="@+id/textView1" android:layout_alignparenttop="true" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="40dp" android:layout_width="wrap_content" android:text="HelloWorld登陆示例"> <edittext android:ems="10" android:hint="请输入账号" android:id="@+id/et_user" android:layout_below="@+id/textView1" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="33dp" android:layout_width="wrap_content"> <requestfocus> </requestfocus></edittext> <edittext android:ems="10" android:hint="请输入密码" android:id="@+id/et_psw" android:inputtype="textPassword" android:layout_below="@+id/et_user" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="40dp" android:layout_width="wrap_content"><button android:id="@+id/btn_login" android:layout_below="@+id/et_psw" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="37dp" android:layout_width="wrap_content" android:text="登陆"></button></edittext></textview></relativelayout> <relativelayout android:layout_height="match_parent" android:layout_width="match_parent" android:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" tools:context=".NaviActivity" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"> <textview android:layout_alignparenttop="true" android:layout_centerhorizontal="true" android:layout_height="wrap_content" android:layout_margintop="46dp" android:layout_width="wrap_content" android:text="登陆成功"> </textview></relativelayout>

3.HTTP的访问公共类，用于处理GET和POST请求。

package com.example.logindemo; import java.util.ArrayList; import java.util.List; import java.util.Map; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.util.EntityUtils; import android.content.Entity; import android.util.Log; public class HttpUtil { // 创建HttpClient对象 public static HttpClient httpClient = new DefaultHttpClient(); public static final String BASE_URL = http://192.168.3.14:8090/HelloWord/; /** * * @param url * 发送请求的URL * @return 服务器响应字符串 * @throws Exception */ public static String getRequest(String url) throws Exception { // 创建HttpGet对象。 HttpGet get = new HttpGet(url); // 发送GET请求 HttpResponse httpResponse = httpClient.execute(get); // 如果服务器成功地返回响应 if (httpResponse.getStatusLine().getStatusCode() == 200) { // 获取服务器响应字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } else { Log.d(服务器响应代码, (new Integer(httpResponse.getStatusLine() .getStatusCode())).toString()); return null; } } /** * * @param url * 发送请求的URL * @param params * 请求参数 * @return 服务器响应字符串 * @throws Exception */ public static String postRequest(String url, Map<string, string=""> rawParams) throws Exception { // 创建HttpPost对象。 HttpPost post = new HttpPost(url); // 如果传递参数个数比较多的话可以对传递的参数进行封装 List<namevaluepair> params = new ArrayList<namevaluepair>(); for (String key : rawParams.keySet()) { // 封装请求参数 params.add(new BasicNameValuePair(key, rawParams.get(key))); } // 设置请求参数 post.setEntity(new UrlEncodedFormEntity(params, UTF-8)); // 发送POST请求 HttpResponse httpResponse = httpClient.execute(post); // 如果服务器成功地返回响应 if (httpResponse.getStatusLine().getStatusCode() == 200) { // 获取服务器响应字符串 String result = EntityUtils.toString(httpResponse.getEntity()); return result; } return null; } } </namevaluepair></namevaluepair></string,>

4.IntentService服务，用于在后台以队列方式处理耗时操作。

package com.example.logindemo; import java.util.HashMap; import android.app.IntentService; import android.content.Intent; import android.util.Log; public class ConnectService extends IntentService { private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE; public ConnectService() { super(TestIntentService); // TODO Auto-generated constructor stub } @Override protected void onHandleIntent(Intent intent) { // TODO Auto-generated method stub /** * 经测试，IntentService里面是可以进行耗时的操作的 * IntentService使用队列的方式将请求的Intent加入队列， * 然后开启一个worker thread(线程)来处理队列中的Intent * 对于异步的startService请求，IntentService会处理完成一个之后再处理第二个 */ Boolean flag = false; //通过intent获取主线程传来的用户名和密码字符串 String username = intent.getStringExtra(username); String password = intent.getStringExtra(password); flag = doLogin(username, password); Log.d(登录结果, flag.toString()); Intent broadcastIntent = new Intent(); broadcastIntent.setAction(ACTION_RECV_MSG); broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT); broadcastIntent.putExtra(result, flag.toString()); sendBroadcast(broadcastIntent); } // 定义发送请求的方法 private Boolean doLogin(String username, String password) { String strFlag = ; // 使用Map封装请求参数 HashMap<string, string=""> map = new HashMap<string, string="">(); map.put(un, username); map.put(pw, password); // 定义发送请求的URL String url = HttpUtil.BASE_URL + queryOrder?un= + username + &pw= + password; //GET方式 // String url = HttpUtil.BASE_URL + LoginServlet; //POST方式 Log.d(url, url); Log.d(username, username); Log.d(password, password); try { // 发送请求 strFlag = HttpUtil.postRequest(url, map); //POST方式 // strFlag = HttpUtil.getRequest(url); //GET方式 Log.d(服务器返回值, strFlag); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } if(strFlag.trim().equals(true)){ return true; }else{ return false; } } } </string,></string,>

5.在AndroidManifest.xml中注册IntentService。注意uses-permission节点，为程序开启访问网络的权限。

<> <manifest android:versioncode="1" android:versionname="1.0" package="com.example.logindemo" xmlns:android="http://schemas.android.com/apk/res/android"> <uses-sdk android:minsdkversion="8" android:targetsdkversion="18"> <uses-permission android:name="android.permission.INTERNET"> <intent-filter> <category android:name="android.intent.category.LAUNCHER"> </category></action></intent-filter> </activity> </activity> <service android:name="com.example.logindemo.ConnectService"> </service> </application> </uses-permission></uses-sdk></manifest>

6.登陆界面处理，注意

按钮监听事件中，使用Intent将要传递的值传给service。接收广播类中，同样使用Intent将要传递的值传给下一个Activity。在onCreate()中，动态注册接收广播类的实例receiver。在接收广播类中，不要使用完毕后忘记注销接收器，否则会报一个Are you missing a call to unregisterReceiver()? 的异常。

package com.example.logindemo; import android.os.Bundle; import android.app.Activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.util.Log; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class MainActivity extends Activity { private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE; private Button loginBtn; private EditText et_username; private EditText et_password; private String userName; private String passWord; private MessageReceiver receiver ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); //动态注册receiver IntentFilter filter = new IntentFilter(ACTION_RECV_MSG); filter.addCategory(Intent.CATEGORY_DEFAULT); receiver = new MessageReceiver(); registerReceiver(receiver, filter); } private void initView() { // TODO Auto-generated method stub et_username = (EditText)findViewById(R.id.et_user); et_password =( EditText)findViewById(R.id.et_psw); loginBtn = (Button)findViewById(R.id.btn_login); loginBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub if(matchLoginMsg()) { // 如果校验成功 Intent msgIntent = new Intent(MainActivity.this, ConnectService.class); msgIntent.putExtra(username, et_username.getText().toString().trim()); msgIntent.putExtra(password, et_password.getText().toString().trim()); startService(msgIntent); } } }); } protected boolean matchLoginMsg() { // TODO Auto-generated method stub userName = et_username.getText().toString().trim(); passWord = et_password.getText().toString().trim(); if(userName.equals()) { Toast.makeText(MainActivity.this, 账号不能为空,Toast.LENGTH_SHORT).show(); return false; } if(passWord.equals()) { Toast.makeText(MainActivity.this, 密码不能为空,Toast.LENGTH_SHORT).show(); return false; } return true; } //接收广播类 public class MessageReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String message = intent.getStringExtra(result); Log.i(MessageReceiver, message); // 如果登录成功 if (message.equals(true)){ // 启动Main Activity Intent nextIntent = new Intent(MainActivity.this, NaviActivity.class); startActivity(nextIntent); // 结束该Activity finish(); //注销广播接收器 context.unregisterReceiver(this); }else{ Toast.makeText(MainActivity.this, 用户名或密码错误，请重新输入!,Toast.LENGTH_SHORT).show(); } } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }

以上就是本文的全部内容，希望对大家的学习有所帮助。