JavaFX : Use a Thread more than once

Question

我是 JavaFX 的新手，线程有点问题:我可以执行它两次，但找不到原因。

这是我的代码的总结:

Task<Void> task = new Task<Void>() {
    @Override public Void call() throws ImageLoadedException, HomographyException, IOException {
        try{
            System.out.println("GO !");
            return null;
        }
        catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
    @Override
    protected void succeeded() {
        super.succeeded();
        System.out.println("SUCCEEDED");
     }
};

@FXML protected void launch(ActionEvent event){
    new Thread(task).start();
}

当我第一次点击启动线程的按钮时，我的任务运行没有任何问题(我的控制台显示“开始!”和“成功”)。

但是，如果我第二次单击，则不会添加任何内容。难道我做错了什么 ？我们不能多次使用一个线程吗？

Answer 1

来自Thread.start()文档:否

It is never legal to start a thread more than once. In particular, a thread may not be restarted once it has completed execution.

来自Concurrency in JavaFX教程:

The Task class defines a one-time object that cannot be reused. If you need a reusable Worker object, use the Service class.

因此，您必须考虑 Service类而不是 Task .

---

编辑:这应该适合您:

Service service = new Service<>(task);

//Updated use this to create a new Service object instead
    Service service = new Service() {
    @Override
    protected Task createTask() {
        return new Task() {
            @Override
            protected Void call() throws Exception {
                //Your codes here
                return null;
            }
        };
    }
};

@FXML protected void launch(ActionEvent event){
     if (!service.isRunning()) {
        service.reset();
        service.start();
    }
}