Java客户端/服务器读取和写入不起作用，也没有错误 [英] Java Client/Server reading and writing doesn't work and no error

问题描述

Client.java

Client.java

package Client;

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

class Client {
        /*
     To send string to server use "out.print(data)"
     To use info sent from server use "in.readLine()"
     */
    int port = 1234;
    String hostname = "localhost";
    String input,output;

    public void send(String text) {
    try {
         Socket skt = new Socket(hostname, port);           /*Connects to server*/

         BufferedReader in = new BufferedReader(new
         InputStreamReader(skt.getInputStream()));          /*Reads from server*/
         System.out.println("Server:" + in.readLine());

         PrintWriter out = new PrintWriter(skt.getOutputStream(), true);
         out.print(text);                                   /*Writes to server*/

         skt.close();
         out.close();    /*Closes all*/
         in.close();
      }

      catch(Exception e) {
         System.out.print("Error Connecting to Server\n");
      } 
    }
   public static void main(String args[]) {
     Client c = new Client();
     c.send("Server is online");    //sends message to server
   }
}

Server.java

Server.java

package Server;

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

class Server {
    /*
     To send string to client use "out.print(data)"
     To use info sent from client use "in.readLine()"
     */
        int port = 1234;
    String input,output;

    public void send(String text) {
    try {
         ServerSocket srvr = new ServerSocket(port);
         Socket skt = srvr.accept();                    /*Waiting for Connection from client*/
         System.out.print("Server has connected!\n");

         PrintWriter out = new PrintWriter(skt.getOutputStream(), true);
         out.print(text);                                                  /*Write/Send to Client*/

          BufferedReader in = new BufferedReader(new
            InputStreamReader(skt.getInputStream()));                   /*Read from Client*/
         System.out.println("Client:" + in.readLine());

         out.close();
         in.close();
         skt.close();               /*Closes all*/
         srvr.close();
      } catch( Exception e) {
         System.out.print("Error Connecting\n");
      } 
    }

   public static void main(String args[]) {
       Server s = new Server();
       s.send("Client is online");  //sends a message to client

   }
}

为什么除了
服务器已连接之外，什么都没做！
发生在我从服务器和客户端发送过来的情况下

why does nothing apart from Server has connected! happen when on both I have sent from the server and client

s.send("X is online");

应该在另一面阅读并在cmd中打印出来吗？

which should be read on the other side and printed out in the cmd?

（是因为bufferreader在printwriter之后被激活并且没有拾取？如果可以的话，我该如何解决？）

(is it because the bufferreader is activated after printwriter and doesn't pick it up? if so how can I fix this?)

推荐答案

除非您发送换行符，否则您的 BufferedReader＃readLine 调用将无限期阻塞。替换

Your BufferedReader#readLine call will block indefinitely unless you send a newline character. Replace

out.print(text); 

与

out.println(text); 

匹配来自以下位置的 BufferedReader＃readLine 调用客户和服务器。

to match the BufferedReader#readLine calls from both client & server.

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