Android 手机经过URL跟WEB服务器通信

package com.edu.qufu.dinner.servlet;
 
 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;
 
 public class LoginServlet extends HttpServlet{
       protected void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,
       IOException{
     	  String username = request.getParameter("username");
     	  String password = request.getParameter("password");
     	  System.out.println(username+":"+password);
     	  response.setContentType("text/html");
     	  response.setCharacterEncoding("utf-8");
     	  PrintWriter out = response.getWriter();
     	  String msg = null;
     	  if(username != null && username.equals("antkingwei") && password != null && password.equals("123")){
     		  msg="登录成功";
     	  }
     	  else {
     		  msg = "登录失败";
     	  }
     	  out.print(msg);
     	  out.flush();
     	  out.close();
     	  
       }
       protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
     	  doGet(request,response);
       }
 }

[代码] 在web.xml里配置一下loginServlet

<?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.5" 
 	xmlns="http://java.sun.com/xml/ns/javaee" 
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
   <display-name></display-name>	
   <welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
     <servlet>
   <servlet-name>FoodServlet</servlet-name>
   <servlet-class>com.edu.qufu.dinner.servlet.FoodServlet</servlet-class>
   </servlet>
   <servlet-mapping>
   <servlet-name>FoodServlet</servlet-name>
   <url-pattern>/FoodServlet</url-pattern>
   </servlet-mapping
     <servlet>
   <servlet-name>LoginServlet</servlet-name>
   <servlet-class>com.edu.qufu.dinner.servlet.LoginServlet</servlet-class>
   </servlet>
   <servlet-mapping>
   <servlet-name>LoginServlet</servlet-name>
   <url-pattern>/LoginServlet</url-pattern>
   </servlet-mapping>
 </web-app>

[代码] android 客户端

package com.android.antking.http.url.connection;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class LoginActivity extends Activity {
	//声明用到的组件
	private Button login,cancel;
	private EditText userName,userPassword;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //事例画所有控件
        login = (Button)this.findViewById(R.id.yes);
        cancel = (Button)this.findViewById(R.id.no);
        userName = (EditText)this.findViewById(R.id.username);
        userPassword = (EditText)this.findViewById(R.id.userpassword);
        //给按钮添加监听事件
        login.setOnClickListener(onClickListenr);
        cancel.setOnClickListener(onClickListenr);
        
    }
    /**
     * 按钮监听类，处理按钮事件
     */
    private View.OnClickListener onClickListenr = new View.OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			if(v.getId()==R.id.yes){
				String nameString = userName.getText().toString();
				String password = userPassword.getText().toString();
			    login(nameString,password);
			}
			if(v.getId()==R.id.no){
				LoginActivity.this.finish();
			}
		}
	};
	/**
	 * 自定义一个消息提示窗口
	 * @param msg
	 */
	private void showDialog(String msg){
		AlertDialog.Builder builder = new AlertDialog.Builder(this);
		builder.setMessage(msg).setCancelable(false).setPositiveButton("确定", 
				new DialogInterface.OnClickListener() {
					
					@Override
					public void onClick(DialogInterface dialog, int id) {
						// TODO Auto-generated method stub
						
					}
				});
		AlertDialog alert = builder.create();
		alert.show();
	}
	private void login(String username,String password){
		//要访问的HttpServlet
		String urlStr="http://192.168.1.100:8080/DinnerClick/LoginServlet?";
		//要传递的数据
		String query = "username="+username+"&password="+password;
		urlStr+=query;
		try{
		URL url =new URL(urlStr);
		//获得连接
		HttpURLConnection conn = (HttpURLConnection)url.openConnection();
		if(true){
			//获得输入流
			InputStream in = conn.getInputStream();
			//创建一个缓冲字节数
			byte[] buffer = new byte[in.available()];
			//在输入流中读取数据并存放到缓冲字节数组中
			in.read(buffer);
			//将字节转换成字符串
			String msg = new String(buffer);
			showDialog(msg);
			in.close();//关闭数据流
		}
		else{
			//否则就关闭连接
			conn.disconnect();
			showDialog("连接失败");
		}
		}catch(Exception e){
			showDialog(e.getMessage());
		}
	}
}

[代码] 别忘了在AndroieManifest.xml里加上网络权限