Question

我正在使用一些多线程应用程序进行java swing。情况是这样的，我需要一个接一个地执行一个线程，即一个输出与第二个相关。我做了以下。

// Class one
public class Samp implements Runnable{
    public Samp(String name) {
       this.setName = name;
    }
    public void run (){
      // Here I have a file extraction method called
      extract(this.getName);
    }

   // Extract Method
   public Boolean extract(String filename){
     // Some extraction Operation.
     // I want to update the jTextField with the current filename under     extraction.
   }
}

// GUI类

public class Welcome extends javax.swing.JFrame {
   SwingWorker<Boolean, Void>worker =  new SwingWorker<Boolean, Void>() {
        @Override
        protected Boolean doInBackground() throws Exception {
            Thread t1 = new Thread(new ZipUtility(fileName));
            t1.start();
            return true;
        }

        // Can safely update the GUI from this method.
        @Override
        protected void done() {
            // Here when this worker is done I wanted to Run worker 2
        }
    };

    SwingWorker<Boolean, Void>worker2 = .........

   // Again when worker2 is done I wanted to run worker 3 and so on.    
 }

我的问题是：

1）如何以完美的顺序运行所有工人。即当完成worker1然后启动worker 2，当worker2完成后再启动worker 3，依此类推。

2）如何使用Samp类中的值更新Welcome类中的文本字段。

提前致谢。

Answer 1

1）如何以完美的顺序运行所有工人。即当完成worker1然后启动worker 2，当worker2完成后再启动worker 3，依此类推。

要记住一个小技巧，您可以将SwingWorker放入ExecutorService

所以，使用像...这样的东西。

public static class Worker extends SwingWorker {

    private int sequence;

    public Worker(int sequence) {
        this.sequence = sequence;
    }

    @Override
    protected Object doInBackground() throws Exception {
        System.out.println(sequence + "...");
        Thread.sleep(500);
        return null;
    }

}

作为测试，您可以使用类似......

的内容

ExecutorService es = Executors.newFixedThreadPool(1);
for (int index = 0; index < 10; index++) {
    es.submit(new Worker(index));
}
es.shutdown();

（您不需要调用shutdown，但我的测试从未允许JVM终止;））

将按照提交的顺序运行工作人员。

现在，如果您想将值从一个SwingWorker提供给另一个{/ 1}}，您可以执行以下操作...

public abstract class ChainedWorker<T, V> extends SwingWorker<T, V> {

    private ChainedWorker<T, ?> next;
    private T previousValue;

    public ChainedWorker(ChainedWorker<T, ?> next) {
        this.next = next;
    }

    public void setPreviousValue(T previousValue) {
        this.previousValue = previousValue;
    }

    @Override
    protected void done() {
        try {
            T previous = get();
            if (next != null) {
                next.setPreviousValue(previous);
                next.execute();
            }
        } catch (InterruptedException | ExecutionException ex) {
            ex.printStackTrace();
        }
    }

}

这只是一个SwingWorker，它允许你在链中提供一个链接（下一个要调用的工作者），它传递了这个SwingWorker生成的值...或者某些类似的< / p>

现在，如果你真的疯了，想要自己扮演角色，可能就像......

public class ChainedWorkerBuilder {

    private List<SwingWorker> workers;
    private SwingWorker current;

    public ChainedWorkerBuilder() {
        workers = new ArrayList<>(25);
    }

    public ChainedWorkerBuilder add(SwingWorker worker) {
        workers.add(worker);
        return this;
    }

    public void execute() {
        if (!workers.isEmpty()) {
            SwingWorker worker = workers.remove(0);
            worker.addPropertyChangeListener(new PropertyChangeListener() {
                @Override
                public void propertyChange(PropertyChangeEvent evt) {
                    if ("state".equals(evt.getPropertyName())) {
                        SwingWorker source = (SwingWorker)evt.getSource();
                        switch (source.getState()) {
                            case DONE:
                                source.removePropertyChangeListener(this);
                                execute();
                                break;
                        }
                    }
                }
            });
        }
    }

}

2）如何使用Samp类中的值更新Welcome类中的文本字段。

我不认为我直接关注您的代码，但是，如果您做了类似的事情......

SwingWorker<Boolean, Void>worker =  new SwingWorker<Boolean, String>() {

    protected Boolean doInBackground() throws Exception {
        publish(fileName);
        ZipUtility zu = new ZipUtility(fileName));
        return zu.extract(fileName);
    }

然后在SwingWorker process方法中，您可以安全地更新用户界面...

    @Override
    protected void process(List<String> chunks) {
        // Grab the last element...
        textfield.setText(chunks.get(chunks.size() - 1));
    }
}

Answer 2

只需致电execute()完成worker2上的worker1：

final SwingWorker<Boolean, Void> worker2 =  new SwingWorker<Boolean, Void>() {
   ...
}

final SwingWorker<Boolean, Void> worker1 =  new SwingWorker<Boolean, Void>() {
    @Override
    protected Boolean doInBackground() throws Exception {
        // Don't start a thread, do your work, otherwise the done will fire
        // too early, also it's pointless to use worker and thread like that
        return true;
    }

    // Can safely update the GUI from this method.
    @Override
    protected void done() {
        // update some ui
        // and start the second part
        worker2.execute();
    }
};

Java Swingworker一个接一个地更新GUI

2 个答案: