線程類中start方法如何調用子類的run方法

Question

請幫助我了解如何通過調用線程類的start方法來調用run方法。

Answer 1

start()方法啟動一個新的執行線程，並進行安排，以便新的執行線程調用run()方法。 確切的機制是特定於OS的。

Answer 2

我建議看一下java.lang.Thread.start()方法的源代碼。 它是一個同步方法，該方法依次調用私有本機方法 ，然后由特定於操作系統的線程機制接管（ 最終調用當前對象的run（）方法 ）

Answer 3

來自文檔

公共無效的開始（）

使該線程開始執行； Java虛擬機將調用此線程的run方法。

結果是兩個線程同時運行：當前線程（從調用返回到start方法）和另一個線程（執行其run方法）。

Answer 4

線程start()調用run()是一個內部進程，而線程依賴於平台。

以下是Java開發人員說的話

java.​lang.​Thread
public synchronized void start()
Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.
The result is that two threads are running concurrently: the current thread (which returns from the call to the start method) and the other thread (which executes its run method).
It is never legal to start a thread more than once. In particular, a thread may not be restarted once it has completed execution.
Throws:
IllegalThreadStateException - if the thread was already started. 
See Also:
Thread.run(), Thread.stop()

您確定不必為此擔心。 如果您正在尋找線程示例，這是一個

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

public class ThreadEx extends JFrame
{
    private JLabel numTxt;
    private JButton click;
    private Thread t = new Thread(new Thread1());

    public ThreadEx()
    {
        numTxt = new JLabel();
        click = new JButton("Start");
        click.addActionListener(new ButtonAction());

        JPanel centerPanel = new JPanel();
        centerPanel.setLayout(new FlowLayout());
        centerPanel.add(numTxt);
        centerPanel.add(click);

        this.add(centerPanel,"Center");

        this.pack();
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private class Thread1 implements Runnable
    {

        @Override
        public void run() 
        {
            try
            {
                for(int i=0;i<100;i++)
                {
                    numTxt.setText(String.valueOf(i));
                    Thread.sleep(1000);
                }
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }

    }

    private class ButtonAction implements ActionListener
    {

        @Override
        public void actionPerformed(ActionEvent e)
        {
            t.start();
        }

    }

    public static void main(String[]args)
    {
        new ThreadEx();
    }
}