android 客户端与web服务器端通信

最近要做一个项目,所以进行了一个小测试.在网上看到的很多Demo，全部是在onCreate()方法中进行连接以及请求服务器端的数据并且在控件中显示的,但是请教了别人之后才知道这种方法现在已经不能用了，必须在主线程中开启一个线程，并且使用Handler这个对象来实现数据的异步请求.然后当请求响应完成之后才会在界面中更新数据,这应该就是android中的异步请求机制吧..下面是整个服务器端以及客户端的代码.首先我服务器端是通过struts来完成的.所以关于struts的jar包以及Json包所依赖的jar包都要导入到web程序中去.以下是服务器端的包图

web.xml文件中要配置过滤器,我是把所有请求都通过struts中的action进行处理的,所以下面是web.xml中的代码

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"id="WebApp_ID" version="3.0"><display-name>YltxServer</display-name><welcome-file-list><welcome-file>index.html</welcome-file><welcome-file>index.htm</welcome-file><welcome-file>index.jsp</welcome-file><welcome-file>default.html</welcome-file><welcome-file>default.htm</welcome-file><welcome-file>default.jsp</welcome-file></welcome-file-list><!-- 定义Struts2的核心控制器：FilterDispatcher --><filter><!-- 定义核心Filter的名称 --><filter-name>struts2</filter-name><!-- 定义Filter的实现类 --><filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class></filter><filter-mapping><filter-name>struts2</filter-name><url-pattern>/*</url-pattern></filter-mapping></web-app>

同时按照struts中的规则，创建一个struts.xml文件，并注册自己写的action

package com.maylor.action;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import net.sf.json.JSONArray;import net.sf.json.JSONObject;import org.apache.struts2.interceptor.ServletRequestAware;import org.apache.struts2.interceptor.ServletResponseAware;import com.opensymphony.xwork2.ActionSupport;public class LoginAction extends ActionSupport implements ServletRequestAware,ServletResponseAware {/** *  */private static final long serialVersionUID = 1L;private HttpServletRequest request;private HttpServletResponse response;public void login() {try {// HttpServletRequest request =ServletActionContext.getRequest();// HttpServletResponse response=ServletActionContext.getResponse();this.response.setContentType("text/html;charset=utf-8");this.response.setCharacterEncoding("UTF-8");// 将要返回的实体对象进行json处理// JSONObject json=JSONObject.fromObject(this.getUsername());// 输出格式如：{"id":1, "username":"zhangsan", "pwd":"123"}// System.out.println(json);// this.response.getWriter().write(json.toString());JSONObject json = new JSONObject();json.put("username", "username");json.put("password", "password");JSONObject json1 = new JSONObject();json1.put("phone", "phone");json1.put("tel", "tel");JSONArray array = new JSONArray();array.add(json);array.add(json1);byte[] jsonBytes = array.toString().getBytes("utf-8");response.setContentLength(jsonBytes.length);response.getOutputStream().write(jsonBytes);/** * JSONObject json=new JSONObject(); json.put("login", "login"); * byte[] jsonBytes = json.toString().getBytes("utf-8"); * response.setContentType("text/html;charset=utf-8"); * response.setContentLength(jsonBytes.length); * response.getOutputStream().write(jsonBytes); * response.getOutputStream().flush(); * response.getOutputStream().close(); **/} catch (Exception e) {e.printStackTrace();}// return null;}@Overridepublic void setServletResponse(HttpServletResponse arg0) {// TODO Auto-generated method stubthis.response = arg0;}@Overridepublic void setServletRequest(HttpServletRequest arg0) {// TODO Auto-generated method stubthis.request = arg0;}}

然后就是客户端的请求了.

下面是android客户端的代码,记住要在AndroidMainifest.xml中加入Internet访问权限

<uses-permission android:name="android.permission.INTERNET">

</uses-permission>

下面就是客户端的代码部分了.

package com.maylor.demo;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import android.annotation.SuppressLint;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.Menu;import android.widget.TextView;public class MainActivity extends Activity {private static String URL = "http://192.168.2.52:8080/YltxServer/login";public Handler mHandler;@SuppressLint("HandlerLeak")@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);getPDAServerData();// Button button = (Button) findViewById(R.id.button1);// button.setOnClickListener(new OnClickListener() {//// @Override// public void onClick(View arg0) {// // TODO Auto-generated method stub// Intent intent = new Intent(MainActivity.this,// PoiSearchActivity.class);// startActivity(intent);// }// });mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {if (msg.what == 1000) {TextView view = (TextView) findViewById(R.id.textview);String str = "";try {JSONArray array = new JSONArray(msg.obj.toString());JSONObject object = array.getJSONObject(0);str = object.getString("username");} catch (JSONException e) {// TODO Auto-generated catch blocke.printStackTrace();}Log.e("wangchao", str);view.setText(str);}}};}/** * 请求服务 *  * @param url */private void getPDAServerData() {new Thread() {public void run() {HttpClient client = new DefaultHttpClient();HttpGet request;String msg = "";try {request = new HttpGet(URL);HttpResponse response = client.execute(request);// 判断请求是否成功if (response.getStatusLine().getStatusCode() == 200) {HttpEntity entity = response.getEntity();if (entity != null) {InputStream in = entity.getContent();BufferedReader buff = new BufferedReader(new InputStreamReader(in));String line = "";while ((line = buff.readLine()) != null) {msg += line;}Message msg1 = mHandler.obtainMessage();msg1.what = 1000;msg1.obj = msg;mHandler.sendMessage(msg1);}}} catch (ClientProtocolException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}.start();}@Overridepublic 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;}}

这个服务就算是全部完成了..整个工程