Java Socket学习笔记（一）- TCP基本使用

一.服务端代码：

import java.net.*; // for Socket, ServerSocket, and InetAddress
import java.io.*; // for IOException and Input/OutputStream

public class TCPEchoServer {

    private static final int BUFSIZE = 32; // Size of receive buffer

    public static void main(String[] args) throws IOException {

        int servPort = 5500;

        // Create a server socket to accept client connection requests
        ServerSocket servSock = new ServerSocket(servPort);

        int recvMsgSize; // Size of received message
        byte[] receiveBuf = new byte[BUFSIZE]; // Receive buffer

        while (true) { // Run forever, accepting and servicing connections
            Socket clntSock = servSock.accept(); // Get client connection

            SocketAddress clientAddress = clntSock.getRemoteSocketAddress();
            System.out.println("Handling client at " + clientAddress);

            InputStream in = clntSock.getInputStream();
            OutputStream out = clntSock.getOutputStream();

            // Receive until client closes connection, indicated by -1 return
            while ((recvMsgSize = in.read(receiveBuf)) != -1) {
                out.write(receiveBuf, 0, recvMsgSize);
            }

            clntSock.close(); // Close the socket. We are done with this client!
        }
        /* NOT REACHED */
    }
}

 

二.客户端代码：

import java.net.*;
import java.io.*;

public class TCPEchoClient {

    public static void main(String[] args) throws IOException {

        String server = "127.0.0.1"; // Server name or IP address
        int servPort = 5500; //// Server port
        byte[] data = "Hi, World".getBytes();

        // Create socket that is connected to server on specified port
        Socket socket = new Socket(server, servPort);
        System.out.println("Connected to server...sending echo string");

        InputStream in = socket.getInputStream();
        OutputStream out = socket.getOutputStream();

        out.write(data); // Send the encoded string to the server

        // Receive the same string back from the server
        int totalBytesRcvd = 0; // Total bytes received so far
        int bytesRcvd; // Bytes received in last read
        while (totalBytesRcvd < data.length) {
            if ((bytesRcvd = in.read(data, totalBytesRcvd, data.length - totalBytesRcvd)) == -1)
                throw new SocketException("Connection closed prematurely");
            totalBytesRcvd += bytesRcvd;
        } // data array is full

        System.out.println("Received: " + new String(data));
        socket.close(); // Close the socket and its streams
    }
}

 

     上述代码的TCP服务端是单线程，一次只能服务一个客户端。

 

 

参考：

1.《Java TCP/IP Socket编程(原书第2版)》