如何取消SwingWorker的执行？

SwingWorker-pool-1-thread-1

SwingWorker

SwingWorker

Executor

java.util.concurrent.CancellationException

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;

public class SwingWorkerExample extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private final JButton startButton, stopButton;
    private JScrollPane scrollPane = new JScrollPane();
    private JList listBox = null;
    private DefaultListModel listModel = new DefaultListModel();
    private final JProgressBar progressBar;
    private mySwingWorker swingWorker;

    public SwingWorkerExample() {
        super(\"SwingWorkerExample\");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().setLayout(new GridLayout(2, 2));
        startButton = makeButton(\"Start\");
        stopButton = makeButton(\"Stop\");
        stopButton.setEnabled(false);
        progressBar = makeProgressBar(0, 99);
        listBox = new JList(listModel);
        scrollPane.setViewportView(listBox);
        getContentPane().add(scrollPane);
        //Display the window.
        pack();
        setVisible(true);
    }
//Class SwingWorker<T,V> T - the result type returned by this SwingWorker\'s doInBackground
//and get methods V - the type used for carrying out intermediate results by this SwingWorker\'s 
//publish and process methods

    private class mySwingWorker extends javax.swing.SwingWorker<ArrayList<Integer>, Integer> {
//The first template argument, in this case, ArrayList<Integer>, is what s returned by doInBackground(), 
//and by get(). The second template argument, in this case, Integer, is what is published with the 
//publish method. It is also the data type which is stored by the java.util.List that is the parameter
//for the process method, which recieves the information published by the publish method.

        @Override
        protected ArrayList<Integer> doInBackground() {
//Returns items of the type given as the first template argument to the SwingWorker class.
            if (javax.swing.SwingUtilities.isEventDispatchThread()) {
                System.out.println(\"javax.swing.SwingUtilities.isEventDispatchThread() returned true.\");
            }
            Integer tmpValue = new Integer(1);
            ArrayList<Integer> list = new ArrayList<Integer>();
            for (int i = 0; i < 100; i++) {
                for (int j = 0; j < 100; j++) { //find every 100th prime, just to make it slower
                    tmpValue = FindNextPrime(tmpValue.intValue());
//isCancelled() returns true if the cancel() method is invoked on this class. That is the proper way
//to stop this thread. See the actionPerformed method.
                    if (isCancelled()) {
                        System.out.println(\"SwingWorker - isCancelled\");
                        return list;
                    }
                }
//Successive calls to publish are coalesced into a java.util.List, which is what is received by process, 
//which in this case, isused to update the JProgressBar. Thus, the values passed to publish range from 
//1 to 100.
                publish(new Integer(i));
                list.add(tmpValue);
            }
            return list;
        }//Note, always use java.util.List here, or it will use the wrong list.

        @Override
        protected void process(java.util.List<Integer> progressList) {
//This method is processing a java.util.List of items given as successive arguments to the publish method.
//Note that these calls are coalesced into a java.util.List. This list holds items of the type given as the
//second template parameter type to SwingWorker. Note that the get method below has nothing to do with the 
//SwingWorker get method; it is the List\'s get method. This would be a good place to update a progress bar.
            if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
                System.out.println(\"javax.swing.SwingUtilities.isEventDispatchThread() + returned false.\");
            }
            Integer percentComplete = progressList.get(progressList.size() - 1);
            progressBar.setValue(percentComplete.intValue());
        }

        @Override
        protected void done() {
            System.out.println(\"doInBackground is complete\");
            if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
                System.out.println(\"javax.swing.SwingUtilities.isEventDispatchThread() + returned false.\");
            }
            try {
//Here, the SwingWorker\'s get method returns an item of the same type as specified as the first type parameter
//given to the SwingWorker class.
                ArrayList<Integer> results = get();
                for (Integer i : results) {
                    listModel.addElement(i.toString());
                }
            } catch (Exception e) {
                System.out.println(\"Caught an exception: \" + e);
            }
            startButton();
        }

        boolean IsPrime(int num) { //Checks whether a number is prime
            int i;
            for (i = 2; i <= num / 2; i++) {
                if (num % i == 0) {
                    return false;
                }
            }
            return true;
        }

        protected Integer FindNextPrime(int num) { //Returns next prime number from passed arg.       
            do {
                if (num % 2 == 0) {
                    num++;
                } else {
                    num += 2;
                }
            } while (!IsPrime(num));
            return new Integer(num);
        }
    }

    private JButton makeButton(String caption) {
        JButton b = new JButton(caption);
        b.setActionCommand(caption);
        b.addActionListener(this);
        getContentPane().add(b);
        return b;
    }

    private JProgressBar makeProgressBar(int min, int max) {
        JProgressBar progressBar1 = new JProgressBar();
        progressBar1.setMinimum(min);
        progressBar1.setMaximum(max);
        progressBar1.setStringPainted(true);
        progressBar1.setBorderPainted(true);
        getContentPane().add(progressBar1);
        return progressBar1;
    }

    private void startButton() {
        startButton.setEnabled(true);
        stopButton.setEnabled(false);
        System.out.println(\"SwingWorker - Done\");
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (\"Start\" == null ? e.getActionCommand() == null : \"Start\".equals(e.getActionCommand())) {
            startButton.setEnabled(false);
            stopButton.setEnabled(true);
// Note that it creates a new instance of the SwingWorker-derived class. Never reuse an old one.
            (swingWorker = new mySwingWorker()).execute(); // new instance
        } else if (\"Stop\" == null ? e.getActionCommand() == null : \"Stop\".equals(e.getActionCommand())) {
            startButton.setEnabled(true);
            stopButton.setEnabled(false);
            swingWorker.cancel(true); // causes isCancelled to return true in doInBackground
            swingWorker = null;
        }
    }

    public static void main(String[] args) {
// Notice that it kicks it off on the event-dispatching thread, not the main thread.
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                SwingWorkerExample swingWorkerExample = new SwingWorkerExample();
            }
        });
    }
}

cancel()

return

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package tools;

import java.util.LinkedList;
import java.util.List;
import javax.swing.SwingUtilities;

/**
 *
 * @author patrick
 */
public abstract class MySwingWorker<R,P> {

    protected abstract R doInBackground() throws Exception;
    protected abstract void done(R rvalue, Exception ex, boolean canceled);
    protected void process(List<P> chunks){}
    protected void progress(int progress){}

    private boolean cancelled=false;
    private boolean done=false;
    private boolean started=false;
    final private Object syncprogress=new Object();
    boolean progressstate=false;
    private int progress=0;
    final private Object syncprocess=new Object();
    boolean processstate=false;
    private LinkedList<P> chunkes= new LinkedList<>();

    private Thread t= new Thread(new Runnable() {
        @Override
        public void run() {
            Exception exception=null;
            R rvalue=null;
            try {
                rvalue=doInBackground();
            } catch (Exception ex) {
                exception=ex;
            }

            //Done:
            synchronized(MySwingWorker.this)
            {
                done=true;
                final Exception cexception=exception;
                final R crvalue=rvalue;
                final boolean ccancelled=cancelled;

                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        done(crvalue, cexception, ccancelled);
                    }
                });
            }

        }
    });    

    protected final void publish(P p)
    {
        if(!Thread.currentThread().equals(t))
            throw new UnsupportedOperationException(\"Must be called from worker Thread!\");
        synchronized(syncprocess)
        {
            chunkes.add(p);
            if(!processstate)
            {
                processstate=true;
                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        List<P> list;
                        synchronized(syncprocess)
                        {
                            MySwingWorker.this.processstate=false;
                            list=MySwingWorker.this.chunkes;
                            MySwingWorker.this.chunkes= new LinkedList<>();
                        }
                        process(list);
                    }
                });
            }
        }
    }

    protected final void setProgress(int progress)
    {
        if(!Thread.currentThread().equals(t))
            throw new UnsupportedOperationException(\"Must be called from worker Thread!\");
        synchronized(syncprogress)
        {
            this.progress=progress;
            if(!progressstate)
            {
                progressstate=true;
                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        int value;
                        //Acess Value
                        synchronized(syncprogress)
                        {
                            MySwingWorker.this.progressstate=false;
                            value=MySwingWorker.this.progress;
                        }
                        progress(value);
                    }
                });
            }
        }
    }

    public final synchronized void execute()
    {
        if(!started)
        {
            started=true;
            t.start();
        }
    }

    public final synchronized boolean isRunning()
    {
        return started && !done;
    }

    public final synchronized boolean isDone()
    {
        return done;
    }

    public final synchronized boolean isCancelled()
    {
        return cancelled;
    }

    public final synchronized void cancel()
    {
        if(started && !cancelled && !done)
        {
            cancelled=true;
            if(!Thread.currentThread().equals(t))
                t.interrupt();
        }
    }

}