Java SocketServer 正在接受来自 Socket 客户端的输入，但 Socket 客户端未接收来自 SocketServer 的输入

Question

我正在尝试学习 Java 网络编程，但遇到了一些障碍。我已经编写了服务器和客户端，但每次尝试连接它们时，我都会立即收到连接关闭错误。然后，我尝试编辑它，但现在出现连接拒绝错误。放弃了这一点，我决定在一个非常简单的服务器上工作来测试 Sockets 和 ServerSockets 的基础知识。这样做，我想出了这两个类:

import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.io.*;

public class SimpleServer {
    public static void main(String[] args) throws Exception {
        System.out.println("hey there");
        ServerSocket server = new ServerSocket(50010);
        Socket socket = server.accept();
        System.out.println("Connection at " + socket);

        InputStream in = socket.getInputStream();
        int c = 0;
        while ((c = in.read()) != -1) {
            System.out.print((char)c);
        }


        OutputStream out = socket.getOutputStream();
        for (byte b : (new String("Thanks for connecting!")).getBytes()) {
            out.write(b);
            out.flush();
        }

        in.close();
        out.close();
        socket.close();
        server.close();
    }
}

和

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

public class SimpleClient {
    public static void main(String[] args) throws Exception {
        System.out.println("Attempting connection");
        Socket s = new Socket("130.49.89.208", 50010);
        System.out.println("Cool");

        OutputStream out = s.getOutputStream();
        for (byte b : (new String("Hey server\r\nThis message is from the client\r\nEnd of message\r\n")).getBytes()) {
            out.write(b);
            out.flush();
        }

        InputStream in = s.getInputStream();
        int c = 0;
        System.out.println("this message will print");
        while ((c = in.read()) != -1) {
            System.out.print((char)c);
            System.out.println("this does not print");
        }

        out.close();
        in.close();
        s.close();
    }
}

服务器完全正常地接收客户端的消息，但是当轮到服务器向客户端写入消息时，一切都会阻塞。

服务器的输出:

-java SimpleServer 
----hey there 
----Connection at Socket[addr=/130.49.89.208,port=59136,localport=50010]
----Hey server
----This message is from the client
----End of message

客户端的输出:

-java SimpleClient
----Attempting connection
----Cool
----this message will print

客户端和服务器都在我的笔记本电脑上运行，通过以太网连接到大学的互联网连接，如果有帮助的话。

Answer 1

根据 Javadocs，InputStream.read() 描述为:

If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

在您的情况下，中断 while 循环的唯一可能是客户端关闭连接，从而导致流结束。

根据您的编码，这是预期的!