客户端：

import java.net.Socket; 
import java.net.InetAddress; 
import java.net.UnknownHostException; 
import java.io.OutputStream; 
import java.io.BufferedReader; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.PrintWriter; 
import java.io.IOException; 
public class TcpClient { 
    public static void main(String[] args) throws IOException { 
        try { 
            byte a[] = { 127,0,0,1 }; 
            InetAddress address = InetAddress.getByAddress(a); 
            Socket socket = new Socket(address,9876); 
            OutputStream os = socket.getOutputStream(); 
            PrintWriter out = new PrintWriter(os,true); 
            InputStream is = socket.getInputStream(); 
            InputStreamReader isr = new InputStreamReader(is); 
            BufferedReader in = new BufferedReader(isr); 
            String line; 
            line = "A line sent by the client"; 
            out.println(line); 
            line = in.readLine(); 
            System.out.println("client got: " + line); 
            out.close(); 
            in.close(); 
            socket.close(); 
        } catch (UnknownHostException e) { 
            System.out.println(e); 
        } catch (IOException e) { 
            System.out.println(e); 
        } 
    } 
}

服务器端：

import java.net.ServerSocket; 
import java.net.Socket; 
import java.io.BufferedReader; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.io.PrintWriter; 
public class TcpServer { 
    public static void main(String[] args) { 
        try { 
            ServerSocket serverSocket = new ServerSocket(9876); 
            Socket socket = serverSocket.accept(); 
/*和Client一样了*/ 
            InputStream is = socket.getInputStream(); 
            InputStreamReader isr = new InputStreamReader(is); 
            BufferedReader in = new BufferedReader(isr); 
            OutputStream os = socket.getOutputStream(); 
            PrintWriter out = new PrintWriter(os,true); 
            String line; 
            while((line = in.readLine()) != null) { 
                 System.out.println("server got: " + line); 
                 line = "A line sent by the server"; 
                 out.println(line); 
            } 
            out.close(); 
            in.close(); 
            socket.close(); 
            serverSocket.close(); 
        } catch (IOException e) { 
            System.out.println(e); 
            System.exit(1); 
        } 
    } 
}

本文转自gnuhpc博客园博客，原文链接：http://www.cnblogs.com/gnuhpc/archive/2012/12/17/2822297.html，如需转载请自行联系原作者