Question

我的TCP服务器

public static void main(String argv[]) throws Exception {
    ServerSocket server = new ServerSocket(3333);
    System.out.println("Server started");
    while (true) {
      Socket socket = server.accept();
      BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      System.out.println("Received: " + input.readLine() + "\n");
    }
  }

我的TCP客户端。

 public static void main(String[] args) throws IOException {
    for (int i = 1; i < 50000; i++) {
      Socket clientSocket = new Socket("localhost", 3333);
      DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
      outToServer.writeBytes(i + "\n");
      clientSocket.close();
      System.out.println(i);
    }
  }

TCP客户端中的循环运行到16374并停止，抛出此异常。

...
...
...
16372
16373
16374
Exception in thread "main" java.net.SocketException: No buffer space available (maximum connections reached?): connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:208)
    at mawia.test.Client.main(Test.java:11)

我的代码出了什么问题？
为什么会出现此错误？
如何解决这个问题？

Answer 1

Fildor是对的，你创建了太多的连接或Socket handles，这内部转换为每个进程允许open-file-handles，这很可能是你破坏了。

理想的方法是让客户端继续在一个连接上发送数据（50000 records），即Socket和Server应该处理在单独的线程中处理这些数据（所以你可以运行多个TCP客户端并发）：

TCP服务器

public static void main(String argv[]) throws Exception {
        ServerSocket server = new ServerSocket(3333);
        System.out.println("Server started");
        while (true) {
          final Socket socket = server.accept();
          Thread t = new Thread(new Runnable() {
            public void run() {
                System.out.println("Server received message from client: ");
                BufferedReader input;
                try {
                    input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    while(!socket.isClosed() && socket.getInputStream().available() > 0){
                        System.out.println("Received: " + input.readLine() + "\n");
                    }
                    System.out.println("Client disconnected from server");
                } catch (IOException e) {
                    //break;
                }
            }
        });
          t.start();
        }
      }

TCP客户端

public static void main(String[] args) throws IOException {
        Socket clientSocket = new Socket("localhost", 3333);
        for (int i = 1; i < 50000; i++) {
            DataOutputStream outToServer = new DataOutputStream(
                    clientSocket.getOutputStream());
            outToServer.writeBytes(i + "\n");
            outToServer.flush();
            System.out.println(i);
        }
        clientSocket.close();
    }

Answer 2

在关闭连接之前，请先尝试在TCP客户端代码中添加flush()，然后与我合作。

简单的TCP客户端 - 服务器应用程序抛出异常

2 个答案: