serversocket启动时并非从主线程开始接受所有连接

Question

我发现从非主线程启动时，ServerSocket 变得部分不负责任。为什么？当我在主线程中启动 ServerSocket 时，一切正常。

主启动类：

public class gui
{
    public static void main(String args[])
    {
        new CpServer();
       
    }

}

启动ServerSocket并接受连接的线程类：

public class CpServer extends Thread {
    private ServerSocket server = null;
    


    public CpServer() 
    {
        
        try {
             server =new ServerSocket(3700,1,InetAddress.getByName("0.0.0.0") );
         } catch (Exception ex) {
             System.out.println( "exception on start socket"+ ex.getMessage());
         }
        
        start();
    }



    public void run() 
    {
    while(true)  
       {
            try {
                
                new NBSrvThr(server.accept()).start();
                System.out.println("Accept");

            } catch (Exception e) 
                {
                   System.out.println("Error acception connection "+e.getMessage());

                }
       }
    }

}

通信线程：

public class NBSrvThr extends Thread {
    private Socket socket = null;
 
    public NBSrvThr(Socket socket) {
        
        this.socket = socket;
    }
     
    public void run() {
 
        try (           
            BufferedReader in = new BufferedReader( new InputStreamReader( socket.getInputStream()));
        ) {
            String inputLine;
            
            while ((inputLine = in.readLine()) != null) 
            {
                System.out.println("got packet: "+inputLine);
                break;
            }
            
            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

客户端测试应用

启动10个连接的主启动类：

public class NBClientManyRuns {

    public static void main(String[] args)  {
 
        for (int i = 0; i < 10; i++) {
            System.out.println("Creating thread "+Integer.toString(i));
            try {
                NBThr.proceed(Integer.toString(i));
            } catch (Exception e) {
                
                System.out.println("Eception itn thr create "+Integer.toString(i));
            }
        }

    }
}

Cleint连接线程：

public class NBThr extends Thread {
    
    public String id;

    
    public static void proceed(String ID)
    {
    NBThr t= new NBThr() ;
    t.id = ID;
    t.start();
    
    }
            
    
    public void run() 
    {
        System.out.println("Starting thread"+ " id="+ id);
        String hostName = "127.0.0.1";
        int portNumber = 3700;
 
        try (
            Socket socket = new Socket(hostName, portNumber);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            ) 
        {
            BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
            socket.getOutputStream().write("hello".getBytes());
            System.out.println("Send done  " + hostName + " id="+ id);  
            
        } catch (Exception e) {
            System.out.println("Exception " + e.getMessage() +" "+ hostName + " id="+ id);
            
        }
        System.out.println("Leaving thread"+ " id="+ id);
    }
    
}

控制台输出：

客户端测试结果显示并非所有连接都被接受：

Creating thread 0
Creating thread 1
Creating thread 2
Creating thread 3
Starting thread id=0
Starting thread id=2
Starting thread id=1
Creating thread 4
Starting thread id=3
Creating thread 5
Starting thread id=4
Creating thread 6
Starting thread id=5
Creating thread 7
Starting thread id=6
Creating thread 8
Creating thread 9
Starting thread id=7
Starting thread id=8
Starting thread id=9
Send done  127.0.0.1 id=2
Send done  127.0.0.1 id=6
Leaving thread id=2
Leaving thread id=6
Send done  127.0.0.1 id=7
Leaving thread id=7
Send done  127.0.0.1 id=4
Leaving thread id=4
Exception Connection refused: connect 127.0.0.1 id=9
Leaving thread id=9
Exception Connection refused: connect 127.0.0.1 id=1
Leaving thread id=1
Exception Connection refused: connect 127.0.0.1 id=8
Exception Connection refused: connect 127.0.0.1 id=5
Exception Connection refused: connect 127.0.0.1 id=0
Leaving thread id=0
Leaving thread id=8
Exception Connection refused: connect 127.0.0.1 id=3
Leaving thread id=3
Leaving thread id=5

服务器控制台仅显示4个接受的连接：

Accept
Accept
Accept
Accept
got packet: hello
got packet: hello
got packet: hello
got packet: hello

Answer 1

我认为线程导致饥饿的线程存在一些问题。我建议将线程池用于此目的