线程可以划分优先级，优先级高的线程得到的CPU资源比较多，也就是CPU优先执行优先级高的线程对象中的任务。
设置线程优先级有助于帮助线程规划器确定下一次选中哪一个线程优先执行。
java中优先级分为1-10个级别
线程优先级的继承特性 例如a线程启迪b线程，则b线程的优先级与a的一样。
代码说话：（很简单）
public class MyThread1 extends Thread {
@Override
public void run() {
System.out.println("MyThread1 run priority=" + this.getPriority());
MyThread2 thread2 = new MyThread2();
thread2.start();
}
}
public class MyThread2 extends Thread {
@Override
public void run() {
System.out.println("MyThread2 run priority=" + this.getPriority());
}
}
public static void main(String[] args) {
System.out.println("main thread begin priority="
+ Thread.currentThread().getPriority());
Thread.currentThread().setPriority(6);
System.out.println("main thread end priority="
+ Thread.currentThread().getPriority());
MyThread1 thread1 = new MyThread1();
thread1.start();
}
优先级具有规则性
public class MyThread1 extends Thread {
@<div style="color:transparent">本文来源gaodai.ma#com搞##代!^码网(</div>Override
public void run() {
long beginTime = System.currentTimeMillis();
long addResult = 0;
for (int j = 0; j < 10; j++) {
for (int i = 0; i < 50000; i++) {
Random random = new Random();
random.nextInt();
addResult = addResult + i;
}
}
long endTime = System.currentTimeMillis();
System.out.println("★★★★★thread 1 use time=" + (endTime - beginTime));
}
}
public class MyThread2 extends Thread {
@Override
public void run() {
long beginTime = System.currentTimeMillis();
long addResult = 0;
for (int j = 0; j < 10; j++) {
for (int i = 0; i < 50000; i++) {
Random random = new Random();
random.nextInt();
addResult = addResult + i;
}
}
long endTime = System.currentTimeMillis();
System.out.println("☆☆☆☆☆thread 2 use time=" + (endTime - beginTime));
}
}
public static void main(String[] args) {
for (int i = 0; i < 5; i++) {
MyThread1 thread1 = new MyThread1();
thread1.setPriority(1);
thread1.start();
MyThread2 thread2 = new MyThread2();
thread2.setPriority(10);
thread2.start();
}
}
高优先级的线程总是先执行完
线程的优先级和代码的执行顺序没有关系
优先级具有随机性
一般优先级较高的线程先执行run()方法，但是这个不能说的但肯定，因为线程的优先级具有 “随机性”也就是较高线程不一定每一次都先执行完。
public class MyThread1 extends Thread {
@Override
public void run() {
long beginTime = System.currentTimeMillis();
for (int i = 0; i < 1000; i++) {
Random random = new Random();
random.nextInt();
}
long endTime = System.currentTimeMillis();
System.out.println("★★★★★thread 1 use time=" + (endTime - beginTime));
}
}
public class MyThread2 extends Thread {
@Override
public void run() {
long beginTime = System.currentTimeMillis();
for (int i = 0; i < 1000; i++) {
Random random = new Random();
random.nextInt();
}
long endTime = System.currentTimeMillis();
System.out.println("☆☆☆☆☆thread 2 use time=" + (endTime - beginTime));
}
}
public static void main(String[] args) {
for (int i = 0; i < 5; i++) {
MyThread1 thread1 = new MyThread1();
thread1.setPriority(5);
thread1.start();
MyThread2 thread2 = new MyThread2();
thread2.setPriority(6);
thread2.start();
}
}
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转载请注明原文链接：Java 线程的优先级(setPriority)案例详解
转载请注明原文链接：Java 线程的优先级(setPriority)案例详解
