java - 简单的java套接字和线程程序的问题

Question

我正在尝试学习如何在 java 中使用线程和套接字。我有一个非常简单的程序。它的功能是让用户输入一个字符串，然后由套接字在线程内运行的服务器接收并打印该消息。我让它打印出“连接已建立!”并接受用户的输入，但它们似乎从未打印出来。是否有某种原因导致收到的消息没有打印到控制台？

这是客户端类:

import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner;

public class Client {
    public static void main(String[] args) throws IOException {
        InetAddress host = InetAddress.getLocalHost();

        TCPServer newServer = new TCPServer(5001);
        Thread thread = new Thread(newServer);
        thread.start();

        Socket socket = new Socket(host,5001);
        String outgoing_message = "";
        Scanner scan = new Scanner(System.in);
        PrintWriter printer = new PrintWriter(socket.getOutputStream());
        while(!outgoing_message.equals("close")) {
            System.out.print("Enter message: ");
            outgoing_message = scan.nextLine();
            printer.println(outgoing_message);
        }
        socket.close();


    }
}

这是 TCPServer 类:

package Package_Two;

import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class TCPServer implements Runnable{
    private Socket socket;
    private ServerSocket serverSocket;



    public TCPServer(int port) throws IOException{
        this.serverSocket = new ServerSocket(port);
    }

    @Override
    public void run(){
        try {
            this.socket = serverSocket.accept();
            System.out.println("Connection established!");
            Scanner scan = new Scanner(socket.getInputStream());
            String incoming_message = "";
            while(!incoming_message.equals("close")){
                incoming_message = scan.nextLine();
                System.out.println("Received message: " + incoming_message);
            }
            socket.close();
        }
        catch(IOException iex){
            iex.printStackTrace();
        }


    }




}

Answer 1

如果您查看所使用的 PrintWriter 构造函数的源代码，您会发现它使用 autoFlush = false 调用另一个构造函数。

我想，你应该将其更改为:

    PrintWriter printer = new PrintWriter(socket.getOutputStream(), true);