多线程控制方法

1：start():用于开始执行run()方法中定义的线程体
2：sleep()：调整java运行时间，指定调用线程的睡眠时间
3：join()：用于调用线程等待本线程结束
4：yield()：暂时停止调用线程并将其放在队列末尾，等待另一轮执行，使同一优先级的其他线程有机会运行

ps:join和yield可以理解为是一对反义词。

下面看代码：

 

import java.io.PrintWriter;

public class MethodTest {
	static PrintWriter out = new PrintWriter(System.out, true);

	public static void main(String[] args) {
		FristThread frist = new FristThread();
		SecondThread second = new SecondThread();
		frist.start();
		second.start();
		try {
			out.println("waiting for first thread to finishing...");
			frist.join();
			out.println("it is a long wait!");
			out.println("waking up second thread...");
			synchronized (second) {
				second.notify();
			}
			out.println("waking for second thread to finishing ...");
			second.join();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}

		out.println("i'm ready to finish too.");
	}

}

class FristThread extends Thread {
	public void run() {
		MethodTest.out.println("First thread starts running");
		try {
			sleep(10000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		MethodTest.out.println("First thread finishes running");
	}
}

class SecondThread extends Thread {
	public synchronized void run() {
		MethodTest.out.println("Second thread starts running");
		MethodTest.out.println("Second thread suspends running");
		try {
			wait();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		MethodTest.out.println("Second thread run again and finishes ");

	}
}

 结果：

 

First thread starts running
waiting for first thread to finishing...
Second thread starts running
Second thread suspends running
First thread finishes running
it is a long wait!
waking up second thread...
waking for second thread to finishing ...
Second thread run again and finishes
i'm ready to finish too.