java - 如果线程启动 Executor，则无法从 Future 和 SwingWorker 获取 ArrayIndexOutOfBoundsException

Question

我通过使用 Executor 为 SwingWorker 玩多线程，我在那里错误地识别了 Vector 中的错误元素，看起来因为这段代码完全忽略了 Vector 中不存在的元素

我的问题 -> 如何/可能以某种方式捕获此异常

简单的输出

run:
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
BUILD SUCCESSFUL (total time: 11 seconds)

取消注释

//changeTableValues1(); // un-comment for get ArrayIndexOutOfBoundsException

一切都正确，我得到 ArrayIndexOutOfBoundsException 并且输出是

run:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 2
        at java.util.Vector.get(Vector.java:694)
        at KondorExport.Util.Help.Table.TableWithExecutor.changeTableValues1(TableWithExecutor.java:70)
        at KondorExport.Util.Help.Table.TableWithExecutor.access$100(TableWithExecutor.java:18)
        at KondorExport.Util.Help.Table.TableWithExecutor$2.actionPerformed(TableWithExecutor.java:61)
        at javax.swing.Timer.fireActionPerformed(Timer.java:271)
        at javax.swing.Timer$DoPostEvent.run(Timer.java:201)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
BUILD SUCCESSFUL (total time: 10 seconds)

来自代码

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;
import java.util.Vector;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import javax.swing.*;
import javax.swing.table.*;

public class TableWithExecutor extends JFrame {

    private static final long serialVersionUID = 1L;
    private String[] columnNames = {"Narrative", "Description"};
    private Object[][] data = {{"About", "About"}, {"Add", "Add"}};
    private JTable table;
    private Executor executor = Executors.newCachedThreadPool();
    private Timer timerRun;
    private int delay = 3000;
    private Vector<String> fwDeals;
    private Vector<String> fwDeals1;

    public TableWithExecutor() {
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            @Override
            public Class getColumnClass(int column) {
                return getValueAt(0, column).getClass();
            }
        };
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane, BorderLayout.CENTER);
        prepareStartShedule();
    }

    private void prepareStartShedule() {
        timerRun = new javax.swing.Timer(delay, startCycle());
        timerRun.setRepeats(true);
        timerRun.start();
    }

    private Action startCycle() {
        return new AbstractAction("Start Shedule") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                executor.execute(new TableWithExecutor.MyTask("StartShedule")); //non on EDT
                //changeTableValues1(); // un-comment for get ArrayIndexOutOfBoundsException
            }
        };
    }

    private void changeTableValues1() {
        fwDeals1 = new Vector<String>();
        fwDeals1.add("First"); // ElementAt(0)
        fwDeals1.add("Second");// ElementAt(1)
        checkDealsInDb1(fwDeals1.get(1), fwDeals1.get(2));
    }

    private void checkDealsInDb1(String Str, String Str1) {
        table.getModel().setValueAt(Str, 0, 1);
        table.getModel().setValueAt(Str1, 1, 1);
    }

    private void changeTableValues() {
        fwDeals = new Vector<String>();
        fwDeals.add("First"); // ElementAt(0)
        fwDeals.add("Second");// ElementAt(1)
        checkDealsInDb(fwDeals.get(1), fwDeals.get(2));
    }

    private void checkDealsInDb(String Str, String Str1) {
        table.getModel().setValueAt(Str, 0, 1);
        table.getModel().setValueAt(Str1, 1, 1);
    }

    public static void main(String[] args) {
        TableWithExecutor frame = new TableWithExecutor();
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.setLocation(150, 150);
        frame.pack();
        frame.setVisible(true);
    }

    private class MyTask extends SwingWorker<Void, Integer> {

        private String str;
        private String namePr;

        MyTask(String str) {
            this.str = str;
            addPropertyChangeListener(new SwingWorkerCompletionWaiter(str, namePr));
        }

        @Override
        protected Void doInBackground() throws Exception {
            if (str.equals("StartShedule")) {
                changeTableValues();
            }
            return null;
        }

        @Override
        protected void process(List<Integer> progress) {
        }

        @Override
        protected void done() {
            if (str.equals("StartShedule")) {
            }
        }
    }

    private class SwingWorkerCompletionWaiter implements PropertyChangeListener {

        private String str;
        private String namePr;

        SwingWorkerCompletionWaiter(String str, String namePr) {
            this.str = str;
            this.namePr = namePr;
        }

        SwingWorkerCompletionWaiter(String namePr) {
            this.namePr = namePr;
        }

        @Override
        public void propertyChange(PropertyChangeEvent event) {
            if ("state".equals(event.getPropertyName()) && SwingWorker.StateValue.DONE == event.getNewValue()) {
                System.out.println("Thread Status with Name :" + str + ", SwingWorker Status is " + event.getNewValue());
            } else if ("state".equals(event.getPropertyName()) && SwingWorker.StateValue.PENDING == event.getNewValue()) {
                System.out.println("Thread Status with Mame :" + str + ", SwingWorker Status is " + event.getNewValue());
            } else if ("state".equals(event.getPropertyName()) && SwingWorker.StateValue.STARTED == event.getNewValue()) {
                System.out.println("Thread Status with Name :" + str + ", SwingWorker Status is " + event.getNewValue());
            } else {
                System.out.println("SomeThing Wrong happends with Thread Status with Name :" + str);
            }
        }
    }
}

编辑:

在 done() 方法中添加了从 Future#get() 重新抛出的内容(@takteek 极好的建议)

@Override
    protected void done() {
        if (str.equals("StartShedule")) {
            try {
                get();
                //errLabel.setText(String.valueOf(get()));
            } catch (InterruptedException ie) {
                ie.printStackTrace();
            } catch (ExecutionException ee) {
                ee.printStackTrace();
            }catch (IllegalStateException is) {
                is.printStackTrace();
            }
        }
    }

但输出仍然是并且只有 Got exception，很难从这个 BlackBox 中获取任何异常

run:
Got exception
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
Got exception
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
Got exception
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
Got exception
Thread Status with Name :StartShedule, SwingWorker Status is STARTED
Thread Status with Name :StartShedule, SwingWorker Status is DONE
BUILD SUCCESSFUL (total time: 13 seconds)

Answer 1

我不确定它会增加多少，但我使用 takteek 的 answer 的变体得到了预期的 Caused by如下图所示。我从命令行运行它以确保 IDE 没有“帮助”。

$ java -cp build/classes TableWithExecutorStartShedule: PENDING -> STARTEDjava.util.concurrent.ExecutionException: java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 2    at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)    at java.util.concurrent.FutureTask.get(FutureTask.java:83)    at javax.swing.SwingWorker.get(SwingWorker.java:582)    at TableWithExecutor$MyTask.done(TableWithExecutor.java:103)    at javax.swing.SwingWorker$5.run(SwingWorker.java:717)    at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.run(SwingWorker.java:814)    at sun.swing.AccumulativeRunnable.run(AccumulativeRunnable.java:95)    at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.actionPerformed(SwingWorker.java:824)    at javax.swing.Timer.fireActionPerformed(Timer.java:291)    at javax.swing.Timer$DoPostEvent.run(Timer.java:221)    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:677)    at java.awt.EventQueue.access$000(EventQueue.java:85)    at java.awt.EventQueue$1.run(EventQueue.java:638)    at java.awt.EventQueue$1.run(EventQueue.java:636)    at java.security.AccessController.doPrivileged(Native Method)    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)    at java.awt.EventQueue.dispatchEvent(EventQueue.java:647)    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)Caused by: java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 2    at java.util.Vector.get(Vector.java:694)    at TableWithExecutor.changeTableValues(TableWithExecutor.java:64)    at TableWithExecutor.access$100(TableWithExecutor.java:14)    at TableWithExecutor$MyTask.doInBackground(TableWithExecutor.java:92)    at TableWithExecutor$MyTask.doInBackground(TableWithExecutor.java:80)    at javax.swing.SwingWorker$1.call(SwingWorker.java:277)    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)    at java.util.concurrent.FutureTask.run(FutureTask.java:138)    at javax.swing.SwingWorker.run(SwingWorker.java:316)    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)    at java.lang.Thread.run(Thread.java:680)StartShedule: STARTED -> DONE

Full code:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.text.DateFormat;
import java.util.Date;
import java.util.List;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import javax.swing.*;
import javax.swing.table.*;

/** @see https://stackoverflow.com/questions/7054627 */
public class TableWithExecutor extends JFrame {

    private static final int delay = 1000;
    private static final DateFormat df = DateFormat.getTimeInstance();
    private String[] columnNames = {"Product", "Availability"};
    private Object[][] data = {columnNames, columnNames, columnNames};
    private DefaultTableModel model;
    private JTable table;
    private Executor executor = Executors.newCachedThreadPool();
    private Timer timer;

    public TableWithExecutor() {
        model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            @Override
            public Class getColumnClass(int column) {
                return getValueAt(0, column).getClass();
            }
        };
        table.setDefaultRenderer(Date.class, new DefaultTableCellRenderer() {

            @Override
            protected void setValue(Object value) {
                setText((value == null) ? "" : df.format(value));
            }
        });
        table.setPreferredScrollableViewportSize(new Dimension(200, 100));
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane, BorderLayout.CENTER);
        timer = new Timer(delay, startCycle());
        timer.setRepeats(true);
        timer.start();
    }

    private Action startCycle() {
        return new AbstractAction(MyTask.STARTSCHEDULE) {

            @Override
            public void actionPerformed(ActionEvent e) {
                executor.execute(new MyTask(MyTask.STARTSCHEDULE));
            }
        };
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                TableWithExecutor frame = new TableWithExecutor();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    private class MyTask extends SwingWorker<List<DateRecord>, DateRecord> {

        private static final String STARTSCHEDULE = "StartSchedule";
        private String name = STARTSCHEDULE;

        MyTask(String name) {
            this.name = name;
            addPropertyChangeListener(new TaskListener(name));
        }

        @Override
        protected List<DateRecord> doInBackground() throws Exception {
            for (int row = 0; row < model.getRowCount(); row++) {
                Date date = new Date();
                date.setTime(date.getTime() + row * 1000);
                publish(new DateRecord(row, date));
            }
            return null;
        }

        @Override
        protected void process(List<DateRecord> chunks) {
            for (DateRecord dr : chunks) {
                model.setValueAt(dr.date, dr.rowNumber, 1);
            }
        }

        @Override
        protected void done() {
            try {
                get();
            } catch (Exception e) {
                e.printStackTrace(System.err);
            }
        }
    }

    private static class DateRecord {

        private int rowNumber;
        private Date date;

        public DateRecord(int recordNumber, Date date) {
            this.rowNumber = recordNumber;
            this.date = date;
        }
    }

    private static class TaskListener implements PropertyChangeListener {

        private String name;

        TaskListener(String name) {
            this.name = name;
        }

        @Override
        public void propertyChange(PropertyChangeEvent e) {
            System.out.println(name + ": "
                + e.getOldValue() + " -> " + e.getNewValue());
        }
    }
}