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;
}

@Override
public void setServletResponse(HttpServletResponse arg0) {
// TODO Auto-generated method stub
this.response = arg0;
}

@Override
public void setServletRequest(HttpServletRequest arg0) {
// TODO Auto-generated method stub
this.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")
@Override
protected 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() {
@Override
public 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 block
e.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();
}

@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;
}
}
这个服务就算是全部完成了..整个工程