java - 在客户端和服务器之间的连接终止之前，Jlabel 组件不再可编辑

Question

我有两个简单的应用程序可以远程关闭、重新启动和注销客户端计算机，我面临的是，当客户端连接到服务器时，Jlabel 组件(statuslabel)不再可编辑，直到连接终止(通过关闭服务器应用程序)我尝试了很多方法，例如使用 socket.isConnected 方法..但没有结果。这是客户端代码:

package homework_5.client;

import java.awt.Color;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.*;
import javax.swing.JOptionPane;

/**
 *
 * @author حسين
 */
public class ClientSideGUI extends javax.swing.JFrame {
Socket socket=null;
String status;
String recievedCommand;
BufferedReader in=null;
Process child;
 /**
 * Creates new form ClientSide
 */
public ClientSideGUI() {
    initComponents();

}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    statuslabel = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    setTitle("Client.");
    addWindowListener(new java.awt.event.WindowAdapter() {
        public void windowOpened(java.awt.event.WindowEvent evt) {
            formWindowOpened(evt);
        }
    });

    statuslabel.setFont(new java.awt.Font("Tahoma", 1, 36)); // NOI18N
    statuslabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(19, 19, 19)
            .addComponent(statuslabel, javax.swing.GroupLayout.PREFERRED_SIZE, 197, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(20, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addContainerGap(55, Short.MAX_VALUE)
            .addComponent(statuslabel, javax.swing.GroupLayout.PREFERRED_SIZE, 40, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(53, 53, 53))
    );

    pack();
}// </editor-fold>

private void formWindowOpened(java.awt.event.WindowEvent evt) {                                  

    try{
          socket=new Socket("127.0.0.1", 1234);
          status="Online";
       }catch(Exception e){status="Offline";}


    //Display status @حسين

                     if(status.equals("Online"))
                     {
                     statuslabel.setForeground(Color.GREEN);
                     statuslabel.setText(status);
                     }
                     if(status.equals("Offline"))
                     {
                     statuslabel.setForeground(Color.RED);
                     statuslabel.setText(status);
                     }


   //Getting the work done :) @حسين
              {
                    while(status.equals("Online"))
                    {
                    try{
                    in=new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    recievedCommand=in.readLine();
                       }catch(IOException e2){JOptionPane.showMessageDialog(rootPane,"Connected to server,\n but facing problems with recieving command\n Exception:"+e2.getClass().getName());}




                    if(recievedCommand.equals("shutdown -s"))
                        {try{    
                             child=Runtime.getRuntime().exec(recievedCommand);
                             }catch(Exception e3){JOptionPane.showMessageDialog(rootPane, "Command Recieved but an error occured on local execution.\n Exception:"+e3.getClass().getName());}
                        }

                    if(recievedCommand.equals("shutdown -r"))
                        {try{    
                             child=Runtime.getRuntime().exec(recievedCommand);
                             }catch(Exception e4){JOptionPane.showMessageDialog(rootPane, "Command Recieved but an error occured on local execution.\n Exception:"+e4.getClass().getName());}
                        }

                    if(recievedCommand.equals("shutdown -l"))
                        {try{    
                             child=Runtime.getRuntime().exec(recievedCommand);
                             }catch(Exception e5){JOptionPane.showMessageDialog(rootPane, "Command Recieved but an error occured on local execution.\n Exception:"+e5.getClass().getName());}
                        }



                    }

              }



 }                                 

 /**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ClientSideGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ClientSideGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ClientSideGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ClientSideGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new ClientSideGUI().setVisible(true);
        }
    });
}
// Variables declaration - do not modify
public javax.swing.JLabel statuslabel;
// End of variables declaration
}

Answer 1

您的套接字连接正在阻塞事件调度线程(EDT)，因此 GUI 无法重新绘制自身。您需要创建一个单独的线程来进行Socket连接。

阅读 Swing 教程中关于 Concurrency 的部分了解更多信息以及使用 Swing Worker 的解决方案。