Java并行-6.线程优先级

• 线程可以有自己的优先级，优先级高的线程在竞争资源时会更有优势，但是这不是绝对的。
• Java线程优先级整型成员变量priority来标识，范围从1到10，数字越大优先级越高。其中有三个静态标量：

public final static int MIN_PRIORITY = 1;
public final static int NORM_PRIORITY = 5;
public final static int MAX_PRIORITY = 10;

以下代码可以展示优先级高的线程倾向于更快完成：

package temp;

public class PriorityDemo {
    public static class HighPriority extends Thread{
        static int count = 0;
        public void run() {
            while(true) {
                synchronized(PriorityDemo.class){
                    count++;
                    if(count > 10000000) {
                        System.out.println("HighPriority is complete!");
                        break;
                    }
                }
            }
        }
    }
    
    public static class LowPriority extends Thread{
        static int count = 0;
        public void run() {
            while(true) {
                synchronized(PriorityDemo.class) {
                    count++;
                    if(count > 10000000) {
                        System.out.println("lowPriority is complete!");
                        break;
                    }
                }
            }
        }
    }
    
    public static void main(String[] args) throws InterruptedException{
        Thread high = new HighPriority();
        LowPriority low = new LowPriority();
        high.setPriority(Thread.MAX_PRIORITY);
        low.setPriority(Thread.MIN_PRIORITY);
        low.start();
        high.start();
    }
}