线程基础-线程的使用（一）

1.获取当前线程

java">package com.ysf;public class Tst01CurrentThread {public static void main(String[] args) {Thread thread = Thread.currentThread();System.out.println(thread);}
}

2.设置线程名称

• 创建线程或线程池时，必须指定线程或线程池的有意义名称，方便出错时回溯

java">package com.ysf;import java.util.concurrent.atomic.AtomicInteger;public class Tst02SetThreadName {static AtomicInteger count = new AtomicInteger();public static void main(String[] args) {Thread t = new Thread(()->{System.out.println(Thread.currentThread().getName());},"module-func-" + count.get());t.start();}
}

3.线程的优先级

• 线程的优先级是指CPU调度的优先级
• 线程优先级最大值：10，最小值：1，默认值5
• 线程优先级并非决定性因素，效果可能并不会很明显

java">package com.ysf;import java.util.concurrent.TimeUnit;public class Tst03SetThreadPriority {public static void main(String[] args) throws InterruptedException {Thread t1 = new Thread(()->{for (int i = 0;i<100;i++){String name = Thread.currentThread().getName();System.out.println(name + "==>" + i);}},"priority-1");Thread t2 = new Thread(()->{for (int i = 0;i<100;i++){String name = Thread.currentThread().getName();System.out.println(name + "==>" + i);}},"priority-2");t1.setPriority(10);t2.setPriority(1);t1.start();t2.start();TimeUnit.SECONDS.sleep(2L);}
}

4.线程的让步

• 可以通过Thread的静态方法yield，让当前线程从运行状态变为就绪状态
• yield方法并不能强制保证CPU不调度自己

java">package com.ysf;import java.util.concurrent.TimeUnit;public class Tst04SetThreadYield {public static void main(String[] args) throws InterruptedException {Thread t1 = new Thread(()->{for (int i = 0;i<100;i++){if (i == 50){Thread.yield();}String name = Thread.currentThread().getName();System.out.println(name + "==>" + i);}},"yield-1");t1.start();Thread t2 = new Thread(()->{for (int i = 0;i<100;i++){String name = Thread.currentThread().getName();System.out.println(name + "==>" + i);}},"yield-2");t2.start();TimeUnit.SECONDS.sleep(2L);}
}

5.线程的休眠

• 让线程从运行状态变为等待状态
• sleep()方法会抛出InterruptedException异常，与结束线程相关

java">package com.ysf;public class Tst05ThreadSleep {public static void main(String[] args) throws InterruptedException {System.out.println(System.currentTimeMillis());Thread.sleep(1000L);System.out.println(System.currentTimeMillis());}
}

6.线程的强占

• 对象方法：join()
  • 既然是一个对象方法，那么就一定需要用线程对象去调用
  • 哪个线程调用了t1.join()，哪个线程就被挂起，直到t1执行完毕后恢复执行
• 对象方法：join(long mill);
  • 被挂起的线程需要等待t1.join(2000L)执行2秒后恢复执行
  • 如果1秒内t1就执行完了，那么被挂起的线程也会恢复执行

java">package com.ysf;public class Tst06ThreadJoin {public static void main(String[] args) throws InterruptedException {Thread t1 = new Thread(()->{String name = Thread.currentThread().getName();for(int i = 0;i<10;i++){System.out.println(name + "==>" + i);}},"join-1");t1.start();for (int i = 0;i<5;i++){// 让t1线程join进来，因为是用t1这个线程对象调用，所以一定是在另外一个线程中让t1加入进来if (i == 1){t1.join();}System.out.println(i);}}
}