Java练习题 - 网络编程

• 编写一服务器端程序，实现读取客户端发送过来的一组整数，表现为一组数与数之间用空格隔开的字符串。对这组整数进行排序处理后，返回相应的字符串给客户端，如果数据格式不正确，则返回错误信息，以本机作为服务器。

public class Server {
  public static void main(String[] args) {
      BufferedReader br = null;
       String clientStr="";
        try {
          //创建一个监听的端口
          ServerSocket ss = new ServerSocket(3838);
          Socket s = null;
         System.out.println("服务器启动...");
          //接受客户端通信请求，并建立专用通信端口
         s = ss.accept();
          System.out.println("有客户端发送请求");
          Send send = new Send(s);
          Thread t1 = new Thread(send);
          t1.start();
         while(true){
              
              //获取客户端通信的信息
               br = new BufferedReader(new InputStreamReader(s.getInputStream()));
              clientStr = br.readLine();
              System.out.println("客户端："+clientStr);
         }
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
}

public class Client {
  
  public static void main(String[] args) {
      BufferedReader br = null;
       String clientStr="";
      try {
          //建立通信端口，并向服务器端发送通信请求
          Socket s = new Socket("127.0.0.1",3838);
          System.out.println("与服务器端建立连接");
          Send send = new Send(s);
          Thread t1 = new Thread(send);
          t1.start();
             while(true){
                  
                  //获取客户端通信的信息
                   br = new BufferedReader(new InputStreamReader(s.getInputStream()));
                   clientStr = br.readLine();
                  System.out.println("服务器端说："+clientStr);
             }
          
      } catch (UnknownHostException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }

  }

}

public class Send implements Runnable{
  Socket s ;
  Scanner in = new Scanner(System.in);
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  public Send(Socket s){
      this.s = s;
  }
  public void run() {
      // TODO Auto-generated method stub
      PrintWriter out = null;
      try {
          while(true){
              out = new PrintWriter(new OutputStreamWriter(s.getOutputStream()),true);
              String str = in.next();
                  //br.readLine();
              out.println(str);
  
          }
          
      } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }finally{
          out.close();
      }
      
  }
  
}

• 编写一个简单的socket通讯程序：
  1）、客户机程序，从控制台输入字符串，发送到服务器端，并将服务器返回的信息显示出来。
  2)、服务器端程序，从客户机接收数据并打印，同时将从标准输入获取的信息发送给客户机
  3）、满足一个服务器可以服务多个客户
  实现效果如图：
  图1：服务器端效果：

  
  
  

  图2：客户器端效果：

  
  

public class Server {
  static List<Socket> l = new ArrayList<Socket>();
  public static void main(String[] args) {
      try {
          ServerSocket so  =new ServerSocket(4001);
          System.out.println("服务器启动...");
          while(true){
              Socket s = so.accept();
              System.out.println(s.getInetAddress()+"发送请求");
              l.add(s);
              One o = new One();
              Thread t = new Thread(o);
              t.start();
          }
          
      } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }
  }
}

public class One implements Runnable {

  public void run() {
      Socket s = Server.l.get(Server.l.size() - 1);
      String str = "";
      SendAll sendAll = new SendAll();
      Thread t1 = new Thread(sendAll);
      t1.start();

      try {
          while (true) {
              BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
              str = br.readLine();
              System.out.println("客户端" + s.getInetAddress() + "说：" + str);
          }
      } catch (IOException e) {
          // TODO Auto-generated catch block
          System.out.println(s.getInetAddress() + "用户下线");
          Server.l.remove(s);
      }

  }

}

public class SendAll implements Runnable{
  
  Scanner in = new Scanner(System.in);
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  
  public void run(){
      PrintWriter out = null;
      try {
          while(true){
              String str =br.readLine();
              for(Socket s:Server.l){
              out = new PrintWriter(new OutputStreamWriter(s.getOutputStream()),true);
              out.println(str);
              }
          }
          
      } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }finally{
          out.close();
      }
  }
}

public class Client {
  
  public static void main(String[] args) {
      BufferedReader br = null;
       String clientStr="";
      try {
          //建立通信端口，并向服务器端发送通信请求
          Socket s = new Socket("127.0.0.1",4001);
          System.out.println("与服务器端建立连接");
          Send send = new Send(s);
          Thread t1 = new Thread(send);
          t1.start();
             while(true){
                  
                  //获取客户端通信的信息
                   br = new BufferedReader(new InputStreamReader(s.getInputStream()));
                   clientStr = br.readLine();
                  System.out.println("服务器端说："+clientStr);
             }
          
      } catch (UnknownHostException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }

  }

}

public class Send implements Runnable{
  Socket s ;
  Scanner in = new Scanner(System.in);
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  public Send(Socket s){
      this.s = s;
  }
  public void run() {
      // TODO Auto-generated method stub
      PrintWriter out = null;
      try {
          while(true){
              out = new PrintWriter(new OutputStreamWriter(s.getOutputStream()),true);
              String str =br.readLine();
              out.println(str);
  
          }
          
      } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }finally{
          out.close();
      }
      
  }   
}