Android通过URL跟web服务器通信那点破事

很多时候我们需要手机跟web服务器通信，比如QQ登录 
这是候我们就需要HttpURLConnection进行通信了 
在设置url的时候注意不要用localhost或者127.0.0.1你会得到一个很伤不起的回答 
Connection refused因为这两个地址都是指的模拟器本身自己， 
所以我们需要在命令行模式里用ipconfig获得本PC的ip地址 
还有就是我们最好先在网页里测试一下服务器是否已经正常工作了，这点也很重要，要不出错误你会很郁闷 

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标签： Android SDK  Tomcat  Tiny Java Web Server

代码片段(7)[全屏查看所有代码]

1. [图片] 未命名7.jpg    

2. [图片] 未命名9.jpg    

3. [图片] 未命名8.jpg    

4. [代码]tomCat服务器端     

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);
      }
}

5. [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 >

6. [代码]android 客户端     跳至 [4] [5] [6] [7] [全屏预览]

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());
        }
    }
}

7. [代码]别忘了在AndroieManifest.xml里加上网络权限     

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