Java - 套接字在客户端断开连接之前不会读取？

Question

所以我用Java制作了带有套接字的服务器和客户端。我试图让服务器从套接字读取/写入，但它仅在客户端断开连接后读取:

        System.out.println("Server initialized");
        clientSocket = server.accept();
        System.out.println("Client connected");

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

        for(int loop = 0;loop<5;loop++){
            out.write("Hello");
            System.out.println(in.readLine());
        }   //end for

问题是，一旦客户端连接，它会显示“客户端已连接”，但随后它不会运行 for 循环。然而，一旦客户端断开连接，服务器就会执行 for 循环并返回

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我在这里缺少什么？这是我的完整服务器代码:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public ServerSocket server;

    public Server(int port){
        try {
            server = new ServerSocket(port);
        } catch (IOException e) {
            System.out.println("Cannot bind to port: "+ port);
            System.exit(-1);
        }

    }   //end constructor

    public void WaitForClient() throws IOException{
        Socket clientSocket = null;

        try {
            System.out.println("Server initialized");
            clientSocket = server.accept();
            System.out.println("Client connected");

            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

            for(int loop = 0;loop<5;loop++){
                out.write("Hello");
                System.out.println(in.readLine());
            }   //end for

        }   //end try
        catch (IOException e) {
            System.out.println("Accept failed");
            System.exit(-1);
        }   //end catch

        clientSocket.close();
        server.close();

    }   //end method

}   //end class

(我的主要方法是从另一个类调用的。)

Answer 1

如果你想立即看到结果，你必须刷新服务器上的流。流在 close() 上自动刷新，这就是您看到输出的原因。