Java Socket编程实例（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。

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