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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