android socket编程实例

android客户端通过socket与服务器进行通信可以分为以下几步:
应用程序与服务器通信可以采用两种模式:TCP可靠通信 和UDP不可靠通信。
(1)通过IP地址和端口实例化Socket,请求连接服务器:
     socket = new Socket(HOST, PORT);   //host:为服务器的IP地址  port:为服务器的端口号
(2)获取Socket流以进行读写,并把流包装进BufferWriter或者PrintWriter:
   PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);  
   这里涉及了三个类:socket.getOutputStream得到socket的输出字节流,OutputStreamWriter是字节流向字符流转换的桥梁,BufferWriter是字符流,然后再包装进PrintWriter。
(3)对Socket进行读写

     if (socket.isConnected()) {
                    if (!socket.isOutputShutdown()) {
                        out.println(msg);
                    }
                }

(4)关闭打开的流

  out.close();

在写代码的过程中一定要注意对socket  输入流  输出流的关闭

下面是一个简单的例子:
main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical"
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent">  
    <TextView
        android:id="@+id/TextView"
        android:singleLine="false"  
        android:layout_width="fill_parent"  
        android:layout_height="wrap_content" />  
    <EditText android:hint="content"
        android:id="@+id/EditText01"  
        android:layout_width="fill_parent"  
        android:layout_height="wrap_content">  
    </EditText>  
    <Button
        android:text="send"
        android:id="@+id/Button02"  
        android:layout_width="fill_parent"  
        android:layout_height="wrap_content">  
    </Button>  
</LinearLayout>

下面是android客户端的源代码:

package com.android.SocketDemo;
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;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class SocketDemo extends Activity implements Runnable {
    private TextView tv_msg = null;
    private EditText ed_msg = null;
    private Button btn_send = null;
//    private Button btn_login = null;
    private static final String HOST = "192.168.1.223";
    private static final int PORT = 9999;
    private Socket socket = null;
    private BufferedReader in = null;
    private PrintWriter out = null;
    private String content = "";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv_msg = (TextView) findViewById(R.id.TextView);
        ed_msg = (EditText) findViewById(R.id.EditText01);
//        btn_login = (Button) findViewById(R.id.Button01);
        btn_send = (Button) findViewById(R.id.Button02);
        try {
            socket = new Socket(HOST, PORT);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
                    socket.getOutputStream())), true);
        } catch (IOException ex) {
            ex.printStackTrace();
            ShowDialog("login exception" + ex.getMessage());
        }
        btn_send.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String msg = ed_msg.getText().toString();
                if (socket.isConnected()) {
                    if (!socket.isOutputShutdown()) {
                        out.println(msg);
                    }
                }
            }
        });
        //启动线程,接收服务器发送过来的数据
        new Thread(SocketDemo.this).start();
    }
    //如果连接出现异常,弹出AlertDialog!
    public void ShowDialog(String msg) {
        new AlertDialog.Builder(this).setTitle("notification").setMessage(msg)
                .setPositiveButton("ok", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                    }
                }).show();
    }
    //读取服务器发来的信息,并通过Handler发给UI线程
    public void run() {
        try {
            while (true) {
                if (socket.isConnected()) {
                    if (!socket.isInputShutdown()) {
                        if ((content = in.readLine()) != null) {
                            content += "\n";
                            mHandler.sendMessage(mHandler.obtainMessage());
                        } else {
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //接收线程发送过来信息,并用TextView显示
    public Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            tv_msg.setText(tv_msg.getText().toString() + content);
        }
    };
}

下面是服务器端得java代码:

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;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Main {
    private static final int PORT = 9999;
    private List<Socket> mList = new ArrayList<Socket>();
    private ServerSocket server = null;
    private ExecutorService mExecutorService = null; //thread pool
    
    public static void main(String[] args) {
        new Main();
    }
    public Main() {
        try {
            server = new ServerSocket(PORT);
            mExecutorService = Executors.newCachedThreadPool();  //create a thread pool
            System.out.print("服务器已启动...");
            Socket client = null;
            while(true) {
                client = server.accept();
                //把客户端放入客户端集合中
                mList.add(client);
                mExecutorService.execute(new Service(client)); //start a new thread to handle the connection
            }
        }catch (Exception e) {
            e.printStackTrace();
        }
    }
    class Service implements Runnable {
            private Socket socket;
            private BufferedReader in = null;
            private String msg = "";
            
            public Service(Socket socket) {
                this.socket = socket;
                try {
                    in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    //客户端只要一连到服务器,便向客户端发送下面的信息。
                    msg = "user" +this.socket.getInetAddress() + "come toal:"
                        +mList.size();
                    this.sendmsg();
                } catch (IOException e) {
                    e.printStackTrace();
                }           
            }
            @Override
            public void run() {
                // TODO Auto-generated method stub
                try {
                    while(true) {
                        if((msg = in.readLine())!= null) {
                            //当客户端发送的信息为:exit时,关闭连接
                            if(msg.equals("exit")) {
                                System.out.println("ssssssss");
                                mList.remove(socket);
                                in.close();
                                msg = "user:" + socket.getInetAddress()
                                    + "exit total:" + mList.size();
                                socket.close();
                                this.sendmsg();
                                break;
                                //接收客户端发过来的信息msg,然后发送给客户端。
                            } else {
                                msg = socket.getInetAddress() + ":" + msg;
                                this.sendmsg();
                            }
                        }
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
          
           //循环遍历客户端集合,给每个客户端都发送信息。
           public void sendmsg() {
               System.out.println(msg);
               int num =mList.size();
               for (int index = 0; index < num; index ++) {
                   Socket mSocket = mList.get(index);
                   PrintWriter pout = null;
                   try {
                       pout = new PrintWriter(new BufferedWriter(
                               new OutputStreamWriter(mSocket.getOutputStream())),true);
                       pout.println(msg);
                   }catch (IOException e) {
                       e.printStackTrace();
                   }
               }
           }
        }    
}

注意在AndroidManifest.xml中加入对网络的访问权限
<uses-permission android:name="android.permission.INTERNET"></uses-permission>

在写代码的过程中一定要注意对套接字和输入/输出流的关闭

解析:除了isClose方法,Socket类还有一个isConnected方法来判断Socket对象是否连接成功。  看到这个名字,也许读者会产生误解。  其实isConnected方法所判断的并不是Socket对象的当前连接状态,  而是Socket对象是否曾经连接成功过,如果成功连接过,即使现在isClose返回true, isConnected仍然返回true。因此,要判断当前的Socket对象是否处于连接状态, 必须同时使用isClose和isConnected方法, 即只有当isClose返回false,isConnected返回true的时候Socket对象才处于连接状态。 虽然在大多数的时候可以直接使用Socket类或输入输出流的close方法关闭网络连接,但有时我们只希望关闭OutputStream或InputStream,而在关闭输入输出流的同时,并不关闭网络连接。这就需要用到Socket类的另外两个方法:shutdownInput和shutdownOutput,这两个方法只关闭相应的输入、输出流,而它们并没有同时关闭网络连接的功能。和isClosed、isConnected方法一样,Socket类也提供了两个方法来判断Socket对象的输入、输出流是否被关闭,这两个方法是isInputShutdown()和isOutputShutdown()。 shutdownInput和shutdownOutput并不影响Socket对象的状态。

 super.onCreate(savedInstanceState);

        // android3.0以后需要加入以下的代码,否则会报socket连接异常的错误
        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build()); 
        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().penaltyLog().penaltyDeath().build());  

        setContentView(R.layout.activity_login);

posted on 2014-05-16 23:24 IOTer 阅读(...) 评论(...) 编辑 收藏

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