各位大虾麻烦帮我看看为什么我GUI界面无法显示？

[hnalenx]

源代码如下，各位大虾麻烦你们给出原因：

import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import java.util.concurrent.*;
import java.awt.*;
public class MutilThreadServer extends JFrame{
   private JTextArea jta=new JTextArea();
   public MutilThreadServer(){
     add(new JScrollPane(jta));
     /*setTitle("MutilThreadServer");
     setSize(500,300);
     setLocationRelativeTo(null);
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     setVisible(true);*/
     ExecutorService executor=Executors.newCachedThreadPool();
     try{
         ServerSocket serverSocket=new ServerSocket(8000);
         jta.append("MutilThreadServer start at "+new Date()+'\n');
         int clientNo=1;
         while(true){
              Socket socket=serverSocket.accept();
              jta.append("Starting thread for client "+clientNo+"at "+new Date()+'\n');
              InetAddress address=socket.getInetAddress();
              jta.append("Client "+clientNo+"'s host name is "+address.getHostName()+'\n');
              jta.append("Client "+clientNo+"'s IP Address is"+address.getHostAddress()+'\n');
              executor.execute(new handleClient(socket));
              clientNo++;
         }
     }
     catch(IOException ex){
        System.err.println(ex);
     }
     finally{
        executor.shutdown();
     }
   }
   public static void main(String[] args){
     MutilThreadServer frame=new MutilThreadServer();
     frame.setTitle("MutilThreadServer");
     frame.setSize(500,300);
     frame.setLocationRelativeTo(null);
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     frame.setVisible(true);
   }
   private class handleClient implements Runnable{
     private Socket socket;
     DataInputStream in;
     DataOutputStream out;
     public handleClient(Socket socket){
       this.socket=socket;
     }
     public void run(){
       try{
           in=new DataInputStream(socket.getInputStream());
           out=new DataOutputStream(socket.getOutputStream());
           double radius=in.readDouble();
           double area=radius*radius*Math.PI;
           out.writeDouble(area);
           jta.append("Radius recevie from client: "+radius+'\n');
           jta.append("Area found: "+area+'\n');
       }
       catch(IOException ex){
           System.out.println(ex);
       }
    }
   }
}

如果把上面代码里面的注释语句的注释符号/* */删除，然后将main函数里面的函数体中语句全部替换成new MutilThreadServer(),然后GUI界面却显示出来了，各位大虾告诉我这是怎么回事？

[aSysBang]

frame.setVisible(true);
问题出在这句话上 默认构造函数里面 创建的frame 是不可见的
你先创建一个不可见的 后来设置属性可见 但是 界面不会因为你修改属性就刷新了
所以设置可见属性要在构造函数里面

[huntor]

try{...}catch..finally...
=> SwingUtilites.invokeLater(new Runnable(){public void run(){ try...catch...finally...}});
可以显示出GUI，
不过好像还是不正常

[huang06252]

1111111

[huang06252]

22222

[ifrancis]

用断点 抛空指针异常

[huntor]

while(true){...}阻塞了线程

[dam528]

友情帮顶，坚决消灭0回复！顶完睡觉

[一头头]

搞不清楚你要怎么样哇

这样也可以用啊

package test11;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import java.util.concurrent.*;
import java.awt.*;
public class MutilThreadServer extends JFrame{
   private JTextArea jta=new JTextArea();
   public MutilThreadServer(){
     add(new JScrollPane(jta));
     setTitle("MutilThreadServer");
     setSize(500,300);
     setLocationRelativeTo(null);
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     setVisible(true);
     ExecutorService executor=Executors.newCachedThreadPool();
     try{
         ServerSocket serverSocket=new ServerSocket(8000);
         jta.append("MutilThreadServer start at "+new Date()+'\n');
         int clientNo=1;
         while(true){
              Socket socket=serverSocket.accept();
              jta.append("Starting thread for client "+clientNo+"at "+new Date()+'\n');
              InetAddress address=socket.getInetAddress();
              jta.append("Client "+clientNo+"'s host name is "+address.getHostName()+'\n');
              jta.append("Client "+clientNo+"'s IP Address is"+address.getHostAddress()+'\n');
              executor.execute(new handleClient(socket));
              clientNo++;
         }
     }
     catch(IOException ex){
        System.err.println(ex);
     }
     finally{
        executor.shutdown();
     }
   }
   public static void main(String[] args){
     MutilThreadServer frame=new MutilThreadServer();
//     frame.setTitle("MutilThreadServer");
//     frame.setSize(500,300);
//     frame.setLocationRelativeTo(null);
//     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//     frame.setVisible(true);
   }
   private class handleClient implements Runnable{
     private Socket socket;
     DataInputStream in;
     DataOutputStream out;
     public handleClient(Socket socket){
       this.socket=socket;
     }
     public void run(){
       try{
           in=new DataInputStream(socket.getInputStream());
           out=new DataOutputStream(socket.getOutputStream());
           double radius=in.readDouble();
           double area=radius*radius*Math.PI;
           out.writeDouble(area);
           jta.append("Radius recevie from client: "+radius+'\n');
           jta.append("Area found: "+area+'\n');
       }
       catch(IOException ex){
           System.out.println(ex);
       }
    }
   }
}

[小小咖啡豆]

来学习学习!

[a281346230]

setVisible(true);

[pl0528]

几处地方我给你修改了一下
public MutilThreadServer() {
super();
setContentPane(new JScrollPane(jta));
// add(new JScrollPane(jta));
/*
* setTitle("MutilThreadServer"); setSize(500,300);
* setLocationRelativeTo(null); setDefaultCloseOperation
* (JFrame.EXIT_ON_CLOSE); setVisible(true);
*/




// while (true) {
// Socket socket = serverSocket.accept();
// jta.append("Starting thread for client " + clientNo + "at "
// + new Date() + '\n');
// InetAddress address = socket.getInetAddress();
// jta.append("Client " + clientNo + "'s host name is "
// + address.getHostName() + '\n');
// jta.append("Client " + clientNo + "'s IP Address is"
// + address.getHostAddress() + '\n');
// executor.execute(new handleClient(socket));
// clientNo++;
// }
你这个循环一直为真吧，都跳不出循环，走不到frame.setVisible(true); 这一句，你怎么看到frame啊?

[空~自由]

while(true) 死循环

[dejinzhao]

一般在调用frame.setVisible(true);前加一句frame.pack();