案例实现的是简单的Socket通信，当client（Androidclient）连接到指定server以后，server向client发送一句话文字信息（你能够拓展其他的了） 先看一下服务端程序的实现吧 Server.java

import java.io.IOException;import java.io.OutputStream;import java.net.ServerSocket;import java.net.Socket;public class Server {/*** @param args* @throws IOException*/public static void main(String[] args) throws IOException {// TODO Auto-generated method stub// 创建一个ServerSocket,用于监听clientsocket的连接请求ServerSocket ss = new ServerSocket(30000);// 採用循环不断接受来自client的请求,server端也相应产生一个Socketwhile (true) {Socket s = ss.accept();OutputStream os = s.getOutputStream();os.write("你好，由于你上线了，所以server发给了你这条信息".getBytes("utf-8"));os.close();s.close();}}}

接下来实现的就是手机client的上线并接收数据了，看一下 MainActivity.java

package com.example.socket;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.Socket;import java.net.UnknownHostException;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity {private TextView display;private Handler handler;private String host;private Button btn;private Socket socket;private String line;private EditText et;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.activity_main);handler = new Handler();btn = (Button) findViewById(R.id.send);et = (EditText)findViewById(R.id.editText1);et.setText("192.168.1.100");OnClickListener listener = new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubnew Thread() {public void run() {try {host = et.getText().toString();socket = new Socket(host, 30000);// 设置10秒之后即觉得是超时socket.setSoTimeout(10000);BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));line = br.readLine();Log.d("Read:", line);br.close();socket.close();} catch (UnknownHostException e) {// TODO Auto-generated catch blockLog.e("UnknownHost", "没找到主机");e.printStackTrace();} catch (IOException e) {Log.e("IOException", "输入输出出现错误");// TODO Auto-generated catch blocke.printStackTrace();}handler.post(new Runnable(){@Overridepublic void run() {// TODO Auto-generated method stubdisplay = (TextView) findViewById(R.id.display);display.setText(line);}});}}.start();}};btn.setOnClickListener(listener);}}

这里需要注意的是，与网络相关的更新UI界面的一定不以在主线程中进行更，必需要用到Handler实现UI更新 好了。看一下布局文件

最后。不得不提的是，由于用到了网络，所以在AndroidMainFest.xml中千万不要忘记加上下面权限