基于 TCP/IP 协议的网络编程

public class TestTCP {
	@Test
	public void client() {
		Socket socket = null;
		OutputStream os = null;
		InputStream is = null;
		try {
			// 创建 Socket 对象以指明目标 Server 的 IP 和端口
			socket = new Socket("127.0.0.1", 9876);
			// 调用该套接字对象的 getOutputStream()方法返回 OutputStream 对象以写出数据
			os = socket.getOutputStream();
			// 后面实际就是 IO 流的应用
			os.write("This is the message sent by client".getBytes());
			// ----------update----------
			// 显式的禁用此套接字的输出流
			socket.shutdownOutput();
			// 接受反馈
			is = socket.getInputStream();
			byte[] b = new byte[10];
			int len;
			while ((len = is.read(b)) != -1) {
				System.out.print(new String(b, 0, len));
			}
			// ----------update----------
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (os != null) {
				try {
					os.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			// socket 也是稀有资源，记得及时关闭
			if (socket != null) {
				try {
					socket.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
	@Test
	public void server() {
		ServerSocket ss = null;
		Socket socket = null;
		InputStream is = null;
		OutputStream os = null;
		try {
			// 创建 ServerSocket 对象指明开放那个端口作为传输端口
			ss = new ServerSocket(9876);
			// 调用 accept()方法，返回一个 Socket 对象，监听 ServerSocket 对应的端口并且接受对该端口的连接
			socket = ss.accept();
			// 调用该套接字对象的 getInputStream()方法返回 InputStream 对象以写入从 client 接收到的数据
			is = socket.getInputStream();
			// 后面实际就是 IO 流的应用
			byte[] b = new byte[10];
			int len;
			while ((len = is.read(b)) != -1) {
				// 打印字节流
				System.out.print(new String(b, 0, len));
			}
			// ----------update----------
			// 反馈一条消息给 Client
			os = socket.getOutputStream();
			os.write("I have received your message".getBytes());
			// ----------update----------
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (os != null) {
				try {
					os.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (is != null) {
				try {
					is.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (socket != null) {
				try {
					socket.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if (ss != null) {
				try {
					ss.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
}