如何在Java中正确获取线程名称？ [英] How to correctly get thread name in Java?

问题描述

我有这个类用于在Java中创建一个线程

I have this class for creating a thread in Java

package org.vdzundza.forms;

import java.awt.Graphics;
import java.awt.Graphics2D;

public class DrawThread extends Thread {
    private static final int THREAD_SLEEP = 500;
    public CustomShape shape;
    private Graphics g;

    public DrawThread(CustomShape shape, Graphics g) {
        this.shape = shape;
        this.g = g;
    }

    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep(THREAD_SLEEP);
                Graphics2D g2d = (Graphics2D) g;
                g2d.setColor(this.shape.getColor());
                g2d.fill(this.shape.getShape());
                System.out.println(String.format("execute thread: %s %s",
                        Thread.currentThread().getName(), this.getName()));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

console将以下文本显示为输出

The console displays the following text as an output

execute thread: red rectangle Thread-2
execute thread: yellow ellipse Thread-3

创建新主题的代码：

customShapes[0] = new CustomShape(
new Rectangle2D.Float(10, 10, 50, 50), Color.RED,
    "red rectangle");
customShapes[1] = new CustomShape(new Ellipse2D.Float(70, 70, 50, 50),
Color.YELLOW, "yellow ellipse");
for (CustomShape cshape: customShapes) {
    Thread t = new Thread(new DrawThread(cshape, this.getGraphics()),
    cshape.getName());
    threads.add(t);
    t.start();
}

我的问题是：为什么 Thread.currentThread（ ）.getName（）返回正确的线程名称，而 this.getName（）返回另一个？

My Question is: Why does Thread.currentThread().getName() return the correct thread name whilst this.getName() returns another?

推荐答案

为什么 Thread.currentThread（）。getName（）返回正确的线程名称，而 this.getName（）返回其他？

Why Thread.currentThread().getName() return correct thread name whilst this.getName() return other?

您的 DrawThread class extends Thread 但是你通过调用启动它：

Your DrawThread class extends Thread but then you start it by calling:

new Thread(new DrawThread(...));

这是不正确的。这意味着从 DrawThread 创建的实际线程不相同的线程。 DrawThread 应该实现 Runnable 和不扩展线程。您的代码有效，因为Thread也是Runnable。

This is not correct. It means that the actual thread that is created is not the same Thread from DrawThread. DrawThread should be implementing Runnable and not extending thread. Your code works because Thread is also a Runnable.

public class DrawThread implements Runnable {

因为有两个线程对象，当你在 DrawThread this.getName（）时$ c>对象不是实际运行的线程，因此其名称未正确设置。仅设置包装线程的名称。在 DrawThread 代码中，您应该调用 Thread.currentThread（）。getName（）来获取真实的名称正在运行的线程。

Because there are two thread objects, when you call this.getName() on the DrawThread object that is not the thread that is actually running so its name is not properly set. Only the wrapping thread's name is set. Inside of the DrawThread code, you should call Thread.currentThread().getName() to get the true name of the running thread.

最后，你的类应该是 DrawRunnable 如果实现了Runnable 。 ： - ）

Lastly, your class should probably be DrawRunnable if it implements Runnable. :-)

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