Android的三种网络通讯方式

Android的三种网络通讯方式

1.标准Java接口

java.net.*提供与联网有关的类，包括流、数据包套接字(socket)、Internet协议、常见Http处理等。比如：创建URL，以及URLConnection/HttpURLConnection对象、设置链接参数、链接到服务器、向服务器写数据、从服务器读取数据等通信。这些在Java网络编程中均有涉及，我们看一个简单的socket编程，实现服务器回发客户端信息。

下面用个例子来说明：

A、客户端：

新建Android项目工程：SocketForAndroid（这个随意起名字了吧，我是以这个建立的！）

下面是main_activity.xml的代码：

<? xml  version = "1.0"  encoding = "utf-8" ?>
< LinearLayout  xmlns:android = "http://schemas.android.com/apk/res/android"
    android:layout_width = "fill_parent"
    android:layout_height = "fill_parent"
    android:orientation = "vertical" >

    < TextView
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"
        android:text = "@string/hello"  />

    < EditText
        android:id = "@+id/message"
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content"
        android:hint = "@string/hint"  />

    < Button
        android:id = "@+id/send"
        android:layout_width = "fill_parent"
        android:layout_height = "wrap_content"
        android:text = "@string/send"  />
</ LinearLayout >

MainActivity.java的代码入下：

package  com.yaowen.socketforandroid;

import  android.os.Bundle;

import  android.support.v7.app.AppCompatActivity;
import  android.view.View;
import  android.widget.Button;
import  android.widget.EditText;

import  java.io.BufferedReader;
import  java.io.BufferedWriter;
import  java.io.IOException;
import  java.io.InputStreamReader;
import  java.io.OutputStreamWriter;
import  java.io.PrintWriter;
import  java.net.Socket;

public  class  MainActivity  extends  AppCompatActivity {
    private  EditText message;
    private  Button send;

    @Override
    protected  void  onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //初始化两个UI控件
        message = (EditText) findViewById(R.id.message);
        send = (Button) findViewById(R.id.send);
        //设置发送按钮的点击事件响应
        send.setOnClickListener( new  View.OnClickListener() {
            @Override
            public  void  onClick(View v) {
                Socket socket =  null ;
                //获取message输入框里的输入的内容
                String msg = message.getText().toString() +  "\r\n" ;
                try  {
                    //这里必须是192.168.3.200，不可以是localhost或者127.0.0.1
                    socket =  new  Socket( "192.168.3.200" ,  18888 );
                    PrintWriter out =  new  PrintWriter(
                            new  BufferedWriter(
                                    new  OutputStreamWriter(
                                            socket.getOutputStream()
                                    )
                            ),  true );
                    //发送消息
                    out.println(msg);
                    //接收数据
                    BufferedReader in =  new  BufferedReader(
                        new  InputStreamReader(
                            socket.getInputStream()
                        )
                    );
                    //读取接收的数据
                    String msg_in = in.readLine();
                    if  ( null  != msg_in) {
                        message.setText(msg_in);
                        System.out.println(msg_in);
                    }  else  {
                        message.setText( "接收的数据有误!" );
                    }
                    //关闭各种流
                    out.close();
                    in.close();
                }  catch  (IOException e) {
                    e.printStackTrace();
                }  finally  {
                    try  {
                        if  ( null  != socket) {
                            //socket不为空时，最后记得要把socket关闭
                            socket.close();
                        }
                    }  catch  (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        });
    }
}

最后别忘记添加访问网络权限：

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

B、服务端：

package  service;
import  java.io.BufferedReader;
import  java.io.BufferedWriter;
import  java.io.IOException;
import  java.io.InputStreamReader;
import  java.io.OutputStreamWriter;
import  java.io.PrintWriter;
import  java.net.ServerSocket;
import  java.net.Socket;
public  class  ServerAndroid  implements  Runnable {
 @Override
 public  void  run() {
  Socket socket =  null ;
  try  {
   ServerSocket server =  new  ServerSocket( 18888 );
   // 循环监听客户端链接请求
   while  ( true ) {
    System.out.println( "start..." );
    // 接收请求
    socket = server.accept();
    System.out.println( "accept..." );
    // 接收客户端消息
    BufferedReader in =  new  BufferedReader( new  InputStreamReader(socket.getInputStream()));
    String message = in.readLine();
    System.out.println(message);
    // 发送消息，向客户端
    PrintWriter out =  new  PrintWriter( new  BufferedWriter( new  OutputStreamWriter(socket.getOutputStream())),
      true );
    out.println( "Server:"  + message);
    // 关闭流
    in.close();
    out.close();
   }
  }  catch  (IOException e) {
   e.printStackTrace();
  }  finally  {
   if  ( null  != socket) {
    try  {
     socket.close();
    }  catch  (IOException e) {
     e.printStackTrace();
    }
   }
  }
 }
 // 启动服务器
 public  static  void  main(String[] args) {
  Thread server =  new  Thread( new  ServerAndroid());
  server.start();
 }
}

C、启动服务器，控制台会打印出“start...”字符串！

D、运行Android项目文件，如下图：

在输入框里输入如下字符串，点发送按钮：

服务器收到客户端发来的消息并打印到控制台：

 

 2、Apache接口

对于大部分应用程序而言JDK本身提供的网络功能已远远不够，这时就需要Android提供的Apache HttpClient了。它是一个开源项目，功能更加完善，为客户端的Http编程提供高效、最新、功能丰富的工具包支持。
下面我们以一个简单例子来看看如何使用HttpClient在Android客户端访问Web。
首先，要在你的机器上搭建一个web应用test，有两个很简单的PHP文件：hello_get.php和hello_post.php！
内容如下：

hello_get.php的代码如下：

<html>
 <body>
  Welcome <?php  echo  $_GET [ "name" ]; ?><br>
  You connected this page on : <?php  echo  $_GET [ "get" ]; ?>
 </body>
</html>

hello_post.php的代码如下：

<html>
<body>
Welcome <?php  echo  $_POST [ "name" ]; ?><br>
You connected this page on : <?php  echo  $_POST [ "post" ]; ?>
</body>
</html>

在原来的Android项目里新建一个Apache活动类：Apache.java，代码如下：

package  com.yaowen.socketforandroid;

import  android.os.Bundle;

import  android.support.v7.app.AppCompatActivity;
import  android.view.View;
import  android.widget.Button;
import  android.widget.TextView;

import  org.apache.http.HttpEntity;
import  org.apache.http.HttpResponse;
import  org.apache.http.NameValuePair;
import  org.apache.http.client.ClientProtocolException;
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  java.io.BufferedReader;
import  java.io.IOException;
import  java.io.InputStreamReader;
import  java.io.UnsupportedEncodingException;
import  java.util.ArrayList;
import  java.util.List;

/**
 * Created by YAOWEN on 2015/11/10.
 */
public  class  ApacheActivity  extends  AppCompatActivity  implements  View.OnClickListener {

    private  TextView textView;
    private  Button get1, post1;

    @Override
    protected  void  onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.apache);


        textView = (TextView) findViewById(R.id.textView);
        get1 = (Button) findViewById(R.id.get);
        post1 = (Button) findViewById(R.id.post);

        get1.setOnClickListener( this );
        post1.setOnClickListener( this );

    }

    @Override
    public  void  onClick(View v) {
        if  (v.getId() == R.id.get) {
            //注意：此处ip不能用127.0.0.1或localhost,Android模拟器已将它自己作为了localhost

            String url =  "http://192.168.3.200/test/hello_get.php?name=yaowen&get=GET" ;
            textView.setText(get(url));
        }
        if  (v.getId() == R.id.post) {

            String url= "http://192.168.3.200/test/hello_post.php" ;
            textView.setText(post(url));
        }

    }

    /**
     * 以post方式发送请求，访问web
     *
     * @param url web地址
     * @return 响应数据
     */
    private  String post(String url) {
        BufferedReader reader =  null ;
        StringBuffer sb =  null ;
        String result =  "" ;
        HttpClient client =  new  DefaultHttpClient();
        HttpPost requset =  new  HttpPost(url);
        //保存要传递的参数
        List<NameValuePair> params =  new  ArrayList<NameValuePair>();
        //添加参数
        params.add( new  BasicNameValuePair( "name" ,  "yaowen" ));
        params.add( new  BasicNameValuePair( "post" , "POST" ));

        try  {
            HttpEntity entity =  new  UrlEncodedFormEntity(params,  "utf-8" );
            requset.setEntity(entity);
            HttpResponse response = client.execute(requset);
            if  (response.getStatusLine().getStatusCode() ==  200 ) {
                System.out.println( "post success" );
                reader =  new  BufferedReader( new  InputStreamReader(response.getEntity().getContent()));
                sb =  new  StringBuffer();
                String line =  "" ;
                String NL = System.getProperty( "line.separator" );
                while  ((line = reader.readLine()) !=  null ) {
                    sb.append(line);
                }
            }

        }  catch  (UnsupportedEncodingException e) {
            e.printStackTrace();
        }  catch  (ClientProtocolException e) {
            e.printStackTrace();
        }  catch  (IOException e) {
            e.printStackTrace();
        }  finally  {
            if  ( null  != reader) {
                try  {
                    reader.close();
                }  catch  (IOException e) {
                    e.printStackTrace();
                }

            }
            if  ( null  != sb) {
                result = sb.toString();
            }
        }

        return  result;
    }

    /**
     * 以get方式发送请求，访问web
     *
     * @param url web地址
     * @return 响应数据
     */
    private  static  String get(String url) {
        BufferedReader bufferedReader =  null ;
        StringBuffer sb =  null ;
        String result =  "" ;
        HttpClient client =  new  DefaultHttpClient();
        HttpGet request =  new  HttpGet(url);
        //发送请求，得到响应
        try  {
            HttpResponse response = client.execute(request);
            //请求成功
            if  (response.getStatusLine().getStatusCode() ==  200 ) {
                bufferedReader =  new  BufferedReader(
                        new  InputStreamReader(
                                response.getEntity()
                                        .getContent()
                        )
                );
                sb =  new  StringBuffer();
                String line =  "" ;
                String NL = System.getProperty( "line.separator" );
                while  ((line = bufferedReader.readLine()) !=  null ) {
                    sb.append(line);
                }
            }
        }  catch  (IOException e) {
            e.printStackTrace();
        }  finally  {
            if  ( null  != bufferedReader) {
                try  {
                    bufferedReader.close();
                    //bufferedReader=null;
                }  catch  (IOException e) {
                    e.printStackTrace();
                }

            }
            if  ( null  != sb) {
                result = sb.toString();
            }
        }
        return  result;
    }
}

新建一个apache.XML文件，如下：

?