Java 中ServerSocket与Socket 通信的简单示例

服务器代码:

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

class ServeOneJabber extends Thread {
  private Socket socket;
  private BufferedReader in;
  private PrintWriter out;
  public ServeOneJabber(Socket s)
      throws IOException {
    socket = s;
    in =
      new BufferedReader(
        new InputStreamReader(
          socket.getInputStream()));
    // Enable auto-flush:
    out =
      new PrintWriter(
        new BufferedWriter(
          new OutputStreamWriter(
            socket.getOutputStream())), true);
    // If any of the above calls throw an
    // exception, the caller is responsible for
    // closing the socket. Otherwise the thread
    // will close it.
    start(); // Calls run()
  }
  public void run() {
    try {
      while (true) { 
        String str = in.readLine(); //接受客户端的数据
        if (str.equals("END")) break;
        System.out.println("Echoing: " + str);
        out.println(str); //给客户端返回一个信息
      }
      System.out.println("closing...");
    } catch (IOException e) {
    } finally {
      try {
        socket.close();
      } catch(IOException e) {}
    }
  }
}

public class MultiJabberServer { 
  static final int PORT = 8080;
  public static void main(String[] args)
      throws IOException {
    ServerSocket s = new ServerSocket(PORT);
    System.out.println("Server Started");
    try {
      while(true) {
        // Blocks until a connection occurs:
        Socket socket = s.accept();
        try {
          new ServeOneJabber(socket);
        } catch(IOException e) {
          // If it fails, close the socket,
          // otherwise the thread will close it:
          socket.close();
        }
      }
    } finally {
      s.close();
    }
  }
}

客户端代码:

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

class JabberClientThread extends Thread {
  private Socket socket;
  private BufferedReader in;
  private PrintWriter out;
  private static int counter = 0;
  private int id = counter++;
  private static int threadcount = 0;
  public static int threadCount() {
    return threadcount;
  }
  public JabberClientThread(InetAddress addr) {
    System.out.println("Making client " + id);
    threadcount++;
    try {
      socket =
        new Socket(addr, MultiJabberServer.PORT);
    } catch(IOException e) {
      // If the creation of the socket fails,
      // nothing needs to be cleaned up.
    }
    try {   
      in =
        new BufferedReader(
          new InputStreamReader(
            socket.getInputStream()));
      // Enable auto-flush:
      out =
        new PrintWriter(
          new BufferedWriter(
            new OutputStreamWriter(
              socket.getOutputStream())), true);
      start();
    } catch(IOException e) {
      // The socket should be closed on any
      // failures other than the socket
      // constructor:
      try {
        socket.close();
      } catch(IOException e2) {}
    }
    // Otherwise the socket will be closed by
    // the run() method of the thread.
  }
  public void run() {
    try {
      for(int i = 0; i < 25; i++) {
        out.println("Client " + id + ": " + i);//向服务器发送数据(或者说向服务器发送请求)
        String str = in.readLine(); //把服务器发过来的数据读取出来
        System.out.println(str);
      }
      out.println("END");
    } catch(IOException e) {
    } finally {
      // Always close it:
      try {
        socket.close();
      } catch(IOException e) {}
      threadcount--; // Ending this thread
    }
  }
}

public class MultiJabberClient {
  static final int MAX_THREADS = 4;
  public static void main(String[] args)
      throws IOException, InterruptedException {
    InetAddress addr =
      InetAddress.getByName(null);
    while(true) {
      if(JabberClientThread.threadCount() < MAX_THREADS)
        new JabberClientThread(addr);
        else
        break;
      Thread.currentThread().sleep(1000);
    }
  }
}