一下是伺服器端原始碼，供大家參考

下面是main.java

package com;

public class Main {

	public static void main(String args[]) {
		new ServerListener().start();
		
	}
}

package com;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

import javax.swing.JOptionPane;

public class ServerListener extends Thread {
	
	int count;
	@Override
	public void run() {
		// TODO Auto-generated method stub
		super.run();
		System.out.println("監聽是否有客戶端連線");
		try {
			ServerSocket serverSocket = new ServerSocket(12345);
			while (true) {
				count++;
				Socket socket = serverSocket.accept();
				JOptionPane.showMessageDialog(null, "有客戶端連線當前伺服器");

				// 一旦有客戶端連線到伺服器，開一個獨立的執行緒
				ChatThread chat = new ChatThread(socket, count);
				chat.start();
				ManagerChatThread.getInstance().add(chat);

			}

		} catch (IOException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}

	}
}
 

package com;

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

public class ChatThread extends Thread {

	int count;
	
	Socket socket;

	StringBuffer sb;

	public ChatThread(Socket socket, int count) {
		// TODO Auto-generated constructor stub
		this.socket = socket;
		this.count = count;
	}

	/**
	 * 向客戶端傳送訊息
	 * 
	 * @param msg
	 */
	public void out(String msg) {
		try {
			socket.getOutputStream().write((msg+"\n").getBytes("utf-8"));
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	@Override
	public void run() {
		// TODO Auto-generated method stub
		super.run();

		// 讀客戶端的內容
		BufferedReader br = null;
		try {
			br = new BufferedReader(new InputStreamReader(
					socket.getInputStream(), "utf-8"));
			String line = null;
			while ((line = br.readLine()) != null) {
				System.out.println("客戶端說"+count+"：" + line);
				// 向客戶端傳送資訊
				ManagerChatThread.getInstance().out(this, line);
			}
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		

	}
}
 

package com;

import java.util.ArrayList;

/**
 * @author Administrator 管理客戶端執行緒物件
 */
public class ManagerChatThread {
	private ArrayList<ChatThread> al = new ArrayList<ChatThread>();

	public static ManagerChatThread instance = new ManagerChatThread();

	private ManagerChatThread() {
	};

	public static ManagerChatThread getInstance() {
		return instance;
	}
	
	public void add(ChatThread chat){
		al.add(chat);
	}

	//向客戶端傳送資訊
	public void out(ChatThread chat, String line){
		for (int i = 0; i < al.size(); i++) {
			if(!al.get(i).equals(chat))
			{
				al.get(i).out(line);
			}
		}
	}
}
 

下滿貼上Android客戶端的程式碼

package com.exp.client;

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

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.TextView;

public class Android_ClientActivity extends Activity implements OnClickListener {
	EditText et;
	TextView tv;
	Socket socket;

	BufferedWriter bw;
	BufferedReader br;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		findViewById(R.id.button1).setOnClickListener(this);
		findViewById(R.id.button2).setOnClickListener(this);

		tv = (TextView) findViewById(R.id.textView1);
		et = (EditText) findViewById(R.id.editText1);
		et.setText("");
		tv.setText("");
	}

	@Override
	public void onClick(View v) {
		if (v.getId() == R.id.button1) {
			// TODO Auto-generated method stub
			new AsyncTask<String, String, Void>() {

				@Override
				protected Void doInBackground(String... params) {
					// TODO Auto-generated method stub
					try {
						socket = new Socket(params[0], 12345);

						bw = new BufferedWriter(new OutputStreamWriter(
								socket.getOutputStream(), "utf-8"));
						
						// 讀伺服器訊息
						br = new BufferedReader(new InputStreamReader(
								socket.getInputStream()));
						
						publishProgress("@sucess");
						String my = null;
						while ((my = br.readLine()) != null) {
							publishProgress(my);
						}

					} catch (UnknownHostException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					} catch (IOException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
					return null;
				}

				@Override
				protected void onProgressUpdate(String... values) {
					// TODO Auto-generated method stub
					super.onProgressUpdate(values);
					if(values[0].equals("@sucess")){
						tv.append("ok\n");
						return;
					}
					tv.append("別人說：" + values[0]+"\n");
				}

			}.execute("10.0.2.2");
		} else if (v.getId() == R.id.button2) {
			// 將EidtText中的內容傳送給伺服器
			String msg = et.getText().toString() + "\n";
			try {
				bw.write(msg);
				bw.flush();

				tv.append("自己說：" + msg);
				et.setText("");
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

		}

	}
}

下面貼上java客戶端的實現，以供大家參考

兩個不同包的Test類

package exp;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scanner = new Scanner(System.in);
		
		try {
			Socket socket = new Socket("192.168.0.112", 6000);
			
			while(true){
				
				//阻塞方法，等待鍵盤輸入
				String value = scanner.next();
				
				OutputStream os = socket.getOutputStream();
				OutputStreamWriter osw = new OutputStreamWriter(os, "utf-8");
				BufferedWriter bw = new BufferedWriter(osw);
				bw.write(value+"\n");
				bw.flush();
			}
		} catch (UnknownHostException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	
	}

}

package com;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		try {
			Socket socket = new Socket("192.168.0.112", 5000);
			
			//客戶端向伺服器傳送資料
			OutputStream os = socket.getOutputStream();
			String value = "abcabc";
			//字串轉化為位元組陣列
			byte c[] = value.getBytes();
			os.write(c);
			
			//客戶端接受伺服器資料
			InputStream is = socket.getInputStream();
			byte b[] = new byte[1024];
			int len = is.read(b);
			String s = new String(b, 0, len);
			System.out.println(s);
			
		} catch (UnknownHostException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}