Question

我在java中创建了一个简单的服务器和客户端，用于发送和接收彼此的消息。目前我将端口号硬编码到代码中，但我想将其从命令行更改为用户输入。在下面的代码中我使用args [0]作为端口号但是当我编译它失败时，任何人都可以帮忙吗？我是java和socket的新手，如果这是一个微不足道的问题，那就很抱歉

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

class SimpleServer
{
 public static void main(String args[]) throws Exception
    {

      //declaring string variables
       String fromclient;
       String toclient;

       //new socket object, listening on port 3000
       ServerSocket Server = new ServerSocket (args[0]);

       //prints when started and no client connected
       System.out.println ("TCPServer Waiting for client on port 3000");

       //infinate loop
       while(true) 
       {

          //listens for connection
          Socket connected = Server.accept();

          //prints clients adddress and port
          System.out.println( " THE CLIENT"+" "+ connected.getInetAddress() +":"+connected.getPort()+" IS CONNECTED ");

          //reads in message form user
          BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));    

          //reads in message from clinet
          BufferedReader inFromClient = new BufferedReader(new InputStreamReader (connected.getInputStream()));

          //prints message to client 
          PrintWriter outToClient = new PrintWriter(connected.getOutputStream(),true);


          //infinate loop
          while ( true )
          {

              //printing instructions for killing connection
                System.out.println("SEND(Type Q or q to Quit):");

              //reading in user input
                toclient = inFromUser.readLine();

              //if user enters q or Q kill connection
                if ( toclient.equals ("q") || toclient.equals("Q") )
                {
                    outToClient.println(toclient);
                    connected.close();
                    break;
                }
                else
                {
                   outToClient.println(toclient);
              }

              //reading from client
                fromclient = inFromClient.readLine();

              //if user enter q or Q kill connection
              if ( fromclient.equals("q") || fromclient.equals("Q") )
              {
                    connected.close();
                    break;
              }

            //printing out the message from client
                else
                {
                  System.out.println( "RECIEVED:" + fromclient );
                } 

               }  

        }
    }
  }

这是即将出现的错误

SimpleServer.java:14: error: no suitable constructor found for ServerSocket(String)
     ServerSocket Server = new ServerSocket (args[0]);

Answer 1

ServerSocket Server = new ServerSocket (Integer.parseInt(args[0]));

args[0]为string，需要在int中解析

Answer 2

您必须使用arg[0] (String)将Integer.parseInt(arg[0])转换为int ServerSocket没有ServerSocket(String)

的构造函数

Answer 3

构造函数参数的类型为int，而赋予main的参数的类型为String。解决方案只是使用Integer.valueOf（args [0]）将参数解析为整数。您可能希望添加更多健壮性检查等 - 但是为了快速解决这个问题，这应该可行。

Java Socket命令行参数

3 个答案: