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Java 工作线程阻塞GUI重绘

java multithreading swing

Java 工作线程阻塞GUI重绘,java,multithreading,swing,swingworker,event-dispatch-thread,Java,Multithreading,Swing,Swingworker,Event Dispatch Thread,我正在尝试为应用程序创建一个登录屏幕。在登录期间，将对MySQL数据库进行许多SQL调用，可能需要几秒钟的时间来设置所有内容。我想通过卡片布局显示一个状态屏幕，并在后台线程运行时更新JLabel 以下是我的工作线程的要点： public class LoginPrepThread extends Thread { private final UIMain parent; public LoginPrepThread(UIMain w){ parent = w;

我正在尝试为应用程序创建一个登录屏幕。在登录期间，将对MySQL数据库进行许多SQL调用，可能需要几秒钟的时间来设置所有内容。我想通过卡片布局显示一个状态屏幕，并在后台线程运行时更新JLabel

以下是我的工作线程的要点：

public class LoginPrepThread extends Thread {

    private final UIMain parent;

    public LoginPrepThread(UIMain w){
        parent = w;
    }

    public void exec(){
        EventQueue.invokeLater(this);
    }

    public void run(){
        try{
            //SqlHelper sql = SqlHelper.instance;
            sleep(500);
            parent.getLoadingLable().setText("Fetching preferences...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Scanning workbench...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Updating permissions...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Finished...Please wait");
            parent.getMainFrame().revalidate();
            sleep(1000);
            parent.getLayout().show(parent.getMainFrame().getContentPane(), "view.main");
        }catch(Exception e){

        }
    }

}
下面是我如何调用它（在JButton事件中，经过身份验证后）：

我现在放入了一些虚拟事件，但是状态标签没有改变……有什么建议吗？

您不应该在事件调度线程上执行任何长时间运行的操作。您正在执行的操作需要3秒钟才能完成。在这3秒钟内，您独占了EDT，无法进行其他GUI更新。

一个简单的swing worker解决了这个问题。我猜我的谷歌搜索不够好

public class LoginPrepThread extends SwingWorker<String,String> {

    private final UIMain parent;

    public LoginPrepThread(UIMain w){
        parent = w;
    }

    @Override
    protected String doInBackground() throws Exception {
        try{
            publish("Fetching preferences...");
            Thread.sleep(1000);
            publish("Updating permissions...");
            Thread.sleep(1000);
            publish("Scanning workbench...");
            Thread.sleep(1000);
            publish("Finalizing...");
            Thread.sleep(2000);
            publish("Finished...Please wait");
            Thread.sleep(1000);
            parent.getLayout().show(parent.getMainFrame().getContentPane(), "view.main");
        }catch(Exception e){

        }
        return null;
    }

    protected void process(List<String> item) {
        parent.getLoadingLable().setText(item.get(0));
    }

}

公共类loginprophread扩展SwingWorker{
主要父母的私人财产；
公共登录线程（UIW）{
父代=w；
}
@凌驾
受保护的字符串doInBackground（）引发异常{
试一试{
发布（“获取首选项…”）；
睡眠（1000）；
发布（“更新权限…”）；
睡眠（1000）；
发布（“扫描工作台…”）；
睡眠（1000）；
发布（“定稿…”）；
《睡眠》（2000年）；
发布（“已完成……请稍候”）；
睡眠（1000）；
parent.getLayout（）.show（parent.getMainFrame（）.getContentPane（），“view.main”）；
}捕获（例外e）{
}
返回null；
}
受保护的无效进程（列表项）{
parent.getLoadingLable（）.setText（item.get（0））；
}
}
理想情况下，您应该实现一个SwingWorker来执行所有繁重的非GUI相关任务。您应该充分利用事件驱动编程的优势

您需要做的事情如下：

  • 在GUI类中实现PropertyChangeListner，监听更新。根据特性更改，更新标签。让一个GUI类处理所有与GUI相关的更新活动始终是一个很好的实践

  • 创建一个SwingWorker，您可以在其中执行后台密集型任务。当有可用的更新时，触发一个属性更改事件，并让GUI类知道有更新

下面是一个小例子，说明您可以做什么：

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.SwingWorker;

/**
 *
 * @author Sujay
 */
public class SimpleWorkerUI extends javax.swing.JFrame implements PropertyChangeListener{

    /**
     * Creates new form SimpleWorkerUI
     */
    public SimpleWorkerUI() {
        initComponents();
        Worker worker = new Worker();
        worker.addPropertyChangeListener(this);
        worker.execute();
    }

    /**
     * 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() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("Current Status: ");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel2)
                .addContainerGap(327, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jLabel2))
                .addContainerGap(20, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

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

    /**
     * @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(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.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 SimpleWorkerUI().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        if("status".equalsIgnoreCase(evt.getPropertyName())){
            String currentStatus = (String) evt.getNewValue();
            jLabel2.setText(currentStatus);
        }
    }
}

class Worker extends SwingWorker<String, String>{

    private static final int FINAL_VALUE = 1000;

    @Override
    protected String doInBackground() throws Exception {
        int counter = 0;

        while(counter < FINAL_VALUE){
            firePropertyChange("status", "", "value is: "+counter);
            try{
                Thread.sleep(100);
            }catch(InterruptedException ixe){
            }
            counter++;
        }
        return null;
    }
}

import java.beans.PropertyChangeEvent；
导入java.beans.PropertyChangeListener；
导入javax.swing.SwingWorker；
/**
*
*@作者苏杰
*/
公共类SimpleWorkerrui扩展了javax.swing.JFrame实现了PropertyChangeListener{
/**
*创建新表单SimpleWorkerRui
*/
公共SimpleWorkerUI（）{
初始化组件（）；
工人=新工人（）；
worker.addPropertyChangeListener（此）；
worker.execute（）；
}
/**
*从构造函数中调用此方法来初始化表单。
*警告：不要修改此代码。此方法的内容始终为
*由表单编辑器重新生成。
*/
@抑制警告（“未选中”）
// 
私有组件（）{
jPanel1=newjavax.swing.JPanel（）；
jLabel1=newjavax.swing.JLabel（）；
jLabel2=newjavax.swing.JLabel（）；
setDefaultCloseOperation（javax.swing.WindowConstants.EXIT_ON_CLOSE）；
jLabel1.setText（“当前状态：”）；
javax.swing.GroupLayout jPanel1Layout=新的javax.swing.GroupLayout（jPanel1）；
setLayout（jPanel1Layout）；
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（jpanellayout.createSequentialGroup（）
.addContainerGap（）
.addComponent（jLabel1）
.addPreferredGap（javax.swing.LayoutStyle.ComponentPlacement.RELATED）
.addComponent（jLabel2）
.addContainerGap（327，简称最大值））
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（jpanellayout.createSequentialGroup（）
.addGap（20,20,20）
.addGroup（jPanel1Layout.createParallelGroup（javax.swing.GroupLayout.Alignment.BASELINE）
.addComponent（jLabel1）
.addComponent（jLabel2））
.addContainerGap（20，简称最大值））
);
javax.swing.GroupLayout=newjavax.swing.GroupLayout（getContentPane（））；
getContentPane（）.setLayout（布局）；
layout.setHorizontalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（jPanel1，javax.swing.GroupLayout.DEFAULT\u SIZE，javax.swing.GroupLayout.DEFAULT\u SIZE，Short.MAX\u值）
);
layout.setVerticalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（jPanel1，javax.swing.GroupLayout.PREFERRED\u SIZE，javax.swing.GroupLayout.DEFAULT\u SIZE，javax.swing.GroupLayout.PREFERRED\u SIZE）
);
包装（）；
}// 
/**
*@param指定命令行参数
*/
公共静态void main（字符串参数[]）{
/*设置Nimbus的外观和感觉*/
//
/*如果Nimbus（在JavaSE6中引入）不可用，请使用默认的外观。
*详情请参阅http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
*/
试一试{
for（javax.swing.UIManager.LookAndFeelInfo:javax.swing.UIManager.getInstalledLookAndFeels（））{
if（“Nimbus”.equals（info.getName（）））{
setLookAndFeel（info.getClassName（））；
打破

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.SwingWorker;

/**
 *
 * @author Sujay
 */
public class SimpleWorkerUI extends javax.swing.JFrame implements PropertyChangeListener{

    /**
     * Creates new form SimpleWorkerUI
     */
    public SimpleWorkerUI() {
        initComponents();
        Worker worker = new Worker();
        worker.addPropertyChangeListener(this);
        worker.execute();
    }

    /**
     * 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() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("Current Status: ");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel2)
                .addContainerGap(327, Short.MAX_VALUE))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(20, 20, 20)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jLabel2))
                .addContainerGap(20, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

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

    /**
     * @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(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(SimpleWorkerUI.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 SimpleWorkerUI().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    // End of variables declaration

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        if("status".equalsIgnoreCase(evt.getPropertyName())){
            String currentStatus = (String) evt.getNewValue();
            jLabel2.setText(currentStatus);
        }
    }
}

class Worker extends SwingWorker<String, String>{

    private static final int FINAL_VALUE = 1000;

    @Override
    protected String doInBackground() throws Exception {
        int counter = 0;

        while(counter < FINAL_VALUE){
            firePropertyChange("status", "", "value is: "+counter);
            try{
                Thread.sleep(100);
            }catch(InterruptedException ixe){
            }
            counter++;
        }
        return null;
    }
}



public class LoginPrepThread extends Thread {

    private final UIMain parent;

    public LoginPrepThread(UIMain w){
        parent = w;
    }

    public void exec(){
        EventQueue.invokeLater(this);
    }

    public void run(){
        try{
            //SqlHelper sql = SqlHelper.instance;
            sleep(500);
            parent.getLoadingLable().setText("Fetching preferences...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Scanning workbench...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Updating permissions...");
            parent.getMainFrame().revalidate();
            sleep(500);
            parent.getLoadingLable().setText("Finished...Please wait");
            parent.getMainFrame().revalidate();
            sleep(1000);
            parent.getLayout().show(parent.getMainFrame().getContentPane(), "view.main");
        }catch(Exception e){
        }
    }
}