服務端：

ServerSocket service = new ServerSocket(7777);
		Socket socket = service.accept();
		InputStream input = socket.getInputStream();
		OutputStream out = socket.getOutputStream();
		BufferedInputStream bufinput = new BufferedInputStream(input);
		BufferedOutputStream bufout = new BufferedOutputStream(out);
		byte [] buf = new byte[1024];
		int len = 0;
		
		StringBuffer sb = new StringBuffer();
        String message = new String(buf,0,bufinput.read(buf));
        System.out.println(message);
        
        out.write("服務端：\n小客你好啊！".getBytes());

client：

Socket client = new Socket("127.0.0.1",7777);
        OutputStream out = client.getOutputStream();
        InputStream input = client.getInputStream();
        BufferedOutputStream bufout = new BufferedOutputStream(out);
        BufferedInputStream bufinput = new BufferedInputStream(input);
        bufout.write("客戶端：\n你好".getBytes());
        bufout.flush();
        byte [] buf = new byte [1024];
        String message = new String(buf,0,bufinput.read(buf));
        System.out.println(message);

java中tcp小樣例