Java 中的 KnockKnockServer

Question

我是 java 网络方面的新手，我正在尝试在 java 中制作一个名为不带 GUI 的即时消息传递的服务器应用程序。所以每当我运行它说的程序时 " 在 class 方法中找不到 Main 方法，请将 main 方法定义为： public static void main(String[] args) 或 JavaFX 应用程序 class 必须扩展 javafx.application.Application" -ECLIPSE

请帮我看看我的代码有什么问题。

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;

// 第一个文件 //
public class 主要{

    public static void main (String[] args) {
    Server s=new Server();
    s.runningserver();

    }
}

//第二个文件//
public class 服务器 {

    private ObjectOutputStream output;
    private ObjectInputStream input;
    private ServerSocket server;
    private Socket connection;

    //wait For Connection,then display connection information
            private void waitforConnection() {
                System.out.println("wait for Someone to Connect.....\n");
                try {
                    connection=server.accept();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    System.out.println("error In Acceptance of Server!!\n...");
                }
            System.out.println(("Connection      Established"+connection.getInetAddress().getHostName()));

            }


            //Setting Up Streams to Get Input and Output

            private void setupStreams(){  
                try {
                    output=new ObjectOutputStream(connection.getOutputStream());
                    output.flush();
                    input=new ObjectInputStream(connection.getInputStream());
                System.out.println("Your Streams are Perfectly Working...");


                } catch (IOException e) {
                    // TODO Auto-generated catch block

                    System.err.println("Error Found! in Streaming Connectionos");
                    e.printStackTrace();
                }
            }

            // While Chatting Method....!!//
                private void whileChatting() throws IOException{
               String Message="You are now Connected!!\n";
               sendMessage(Message);

               //abletoType(true);
               do{
                   try{
                   Message=(String) input.readObject();
                   System.out.println("\n"+Message);
               }       
                catch(ClassNotFoundException e ){
                    System.out.println("wtf---Fuck\n YOu\n Bloody\n HAcker!!!\n");
                }



               }
                  while(!Message.equals("CLIENT--END"));

                    }
                // Closing All Streams and Socket after you are done//
                private void closeCrap(){
                    System.out.println("\nClosing Connection...........Bye Bye\n");
                    //abletoType(false);
                    try {
                        output.close();
                        input.close();
                        connection.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
        System.out.println("Couldn't Close Connections!");
                    }

                }
                //Sending Messages to Client
                private void sendMessage(String message){
                    try {

                        output.writeObject("SERVER--- "+message);

                        output.flush();
            System.out.println("\nServer- "+message);

                    } catch (IOException e) {
                        // TODO Auto-generated catch block




                    e.printStackTrace();
        System.out.println("Dude I cant Send yeaah..");
                    }

                }






    // Setting up the Server

public void runningserver(){
        try {
            server=new ServerSocket(4444,100);
            while(true){try{
                //connect and Have connection
                waitforConnection();
                setupStreams();
                whileChatting();
            }
            finally{
                closeCrap();
            }
            }   
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }



        }




    }

Answer 1

main方法必须是class:

的一个方法

import java.net.Socket;

public class Server {

    public static void main (String[] args) {
      Server s=new Server();
      s.runningserver();
    }

所以它必须在 class 声明之后。

Answer 2

编辑：这是解决方案，我检查了它，对我来说它有效（运行 MainClass.java 文件！）： //MainClass.java 文件:

public class MainClass {
    public static void main (String[] args) {
    Server s=new Server();
    s.runningserver();
    } 
}

//Server.java 文件:

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    private ObjectOutputStream output;
    private ObjectInputStream input;
    private ServerSocket server;
    private Socket connection;

    // wait For Connection,then display connection information
    private void waitforConnection() {
        System.out.println("wait for Someone to Connect.....\n");
        try {
            connection = server.accept();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            System.out.println("error In Acceptance of Server!!\n...");
        }
        System.out.println(("Connection      Established" + connection
                .getInetAddress().getHostName()));

    }

    // Setting Up Streams to Get Input and Output

    private void setupStreams() {
        try {
            output = new ObjectOutputStream(connection.getOutputStream());
            output.flush();
            input = new ObjectInputStream(connection.getInputStream());
            System.out.println("Your Streams are Perfectly Working...");

        } catch (IOException e) {
            // TODO Auto-generated catch block

            System.err.println("Error Found! in Streaming Connectionos");
            e.printStackTrace();
        }
    }

    // While Chatting Method....!!//
    private void whileChatting() throws IOException {
        String Message = "You are now Connected!!\n";
        sendMessage(Message);

        // abletoType(true);
        do {
            try {
                Message = (String) input.readObject();
                System.out.println("\n" + Message);
            } catch (ClassNotFoundException e) {
                System.out.println("wtf---Fuck\n YOu\n Bloody\n HAcker!!!\n");
            }

        } while (!Message.equals("CLIENT--END"));

    }

    // Closing All Streams and Socket after you are done//
    private void closeCrap() {
        System.out.println("\nClosing Connection...........Bye Bye\n");
        // abletoType(false);
        try {
            output.close();
            input.close();
            connection.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            System.out.println("Couldn't Close Connections!");
        }

    }

    // Sending Messages to Client
    private void sendMessage(String message) {
        try {

            output.writeObject("SERVER--- " + message);

            output.flush();
            System.out.println("\nServer- " + message);

        } catch (IOException e) {
            // TODO Auto-generated catch block

            e.printStackTrace();
            System.out.println("Dude I cant Send yeaah..");
        }

    }

    // Setting up the Server

    public void runningserver() {
        try {
            server = new ServerSocket(4444, 100);
            while (true) {
                try {
                    // connect and Have connection
                    waitforConnection();
                    setupStreams();
                    whileChatting();
                } finally {
                    closeCrap();
                }
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

我可以运行无一例外。

问题是你的主要方法

public static void main (String[] args) {}

不在class你所在的运行吧。

//separate file A.java
public class A
{}

//separate file B.java
public class B
{
    public static void main (String[] args) {}

}

如果你现在运行 B，它可以工作，因为 B.java 有一个 main 方法。但是：如果你运行 A.java 它说：找不到主要方法。你要的文件运行（A、B等必须定义了main方法）如果你运行一个 java 文件，它将寻找一个 main 方法（执行的起点）。

Java 中的 KnockKnockServer

KnockKnockServer in Java

java

server