6 sleep与yield的比较
6 sleep与yield的比较
sleep
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调用 sleep 会让当前线程从 Running 进入 Timed Waiting 状态(阻塞)
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其它线程可以使用 interrupt 方法打断正在睡眠的线程,这时 sleep 方法会抛出 InterruptedException
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睡眠结束后的线程未必会立刻得到执行
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建议用 TimeUnit 的 sleep 代替 Thread 的 sleep 来获得更好的可读性
yield
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调用 yield 会让当前线程从 Running 进入 Runnable 就绪状态,然后调度执行其它线程 。同时,该线程在就绪状态时,CPU可能会分配资源给它,使其进入运行态。
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具体的实现依赖于操作系统的任务调度器
yield和线程优先级代码实例
//代码实例 public class YieldAndPriority { public static void main(String[] args) { Runnable task1 = new Runnable() { @Override public void run() { int count = 0; //yield,让线程进入就绪态,CPU可能会调度该线程,使得该线程变为执行状态 Thread.yield(); while (true) { System.out.println("-------> task1 count=" + count++); } } }; Runnable task2 = new Runnable() { @Override public void run() { int count = 0; while (true) { System.out.println(" --------------------------------------> task2 count=" + count++); } } }; Thread t1 = new Thread(task1, "t1"); Thread t2 = new Thread(task2, "t2"); //设置优先级1-10 越大优先级越高 t1.setPriority(1); t2.setPriority(10); t1.start(); t2.start(); } }
//输出结果 ... --------------------------------------> task2 count=34436 --------------------------------------> task2 count=34437 --------------------------------------> task2 count=34438 --------------------------------------> task2 count=34439 --------------------------------------> task2 count=34440 --------------------------------------> task2 count=34441 --------------------------------------> task2 count=34442 --------------------------------------> task2 count=34443 --------------------------------------> task2 count=34444 -------> task1 count=42407 -------> task1 count=42408 -------> task1 count=42409 -------> task1 count=42410 -------> task1 count=42411 -------> task1 count=42412 -------> task1 count=42413 -------> task1 count=42414 -------> task1 count=42415 -------> task1 count=42416 进程已结束,退出代码130