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Java多线程开发(线程状态、优先级、用户线程和守护线程)

程序员文章站 2022-06-28 17:14:03
Java多线程03_线程状态、优先级、用户线程和守护线程线程方法:setPriority()更改线程优先级static void sleep()线程休眠void join()插队static void yield()礼让void interrupt()中断线程boolean isAlive()是否存活停止线程:不推荐JDK提供的stop()、destory()方法【已废弃】推荐让线程正常停止,不要死循环!建议使用一个标志位进行终止,当...

Java多线程03_线程状态、优先级、用户线程和守护线程


Java多线程开发(线程状态、优先级、用户线程和守护线程)


线程方法:

setPriority() 更改线程优先级 static void sleep() 线程休眠 void join() 插队 static void yield() 礼让 void interrupt() 中断线程 boolean isAlive() 是否存活 

停止线程:

不推荐JDK提供的stop()、destory()方法 【已废弃】

推荐让线程正常停止,不要死循环!

建议使用一个标志位进行终止,当flag=false,则终止线程运行

public class TestStop implements Runnable{ private boolean flag = true; @Override public void run() { int i = 0; while(flag) { System.out.println("run...Thread"+i++); } } //设置公开方法利用标志位停止线程 public void stopThread() { this.flag = false; System.out.println("线程停止了"); } public static void main(String[] args) { TestStop testStop = new TestStop(); new Thread(testStop).start(); for(int i=0;i<1000;i++) { System.out.println("main...,"+i); if(i==900) { testStop.stopThread(); } } } } 

线程休眠:

sleep方法存在异常:InterruptedException

sleep时间结束,线程进入就绪状态

每个对象都有一个锁,sleep不会释放锁

Thread.sleep(1000); 

线程礼让:

让当前执行的线程暂停,但不阻塞

将线程从运行状态转为就绪状态

礼让不一定成功,看cpu心情

Thread.yield(); 

Join合并线程,待此线程执行完成后,再执行其他线程,其他线程阻塞(插队)

main线程和Thread线程交替执行,当main线程执行到200时,Thread线程插队,一直到执行结束,main线程才能重新执行

package com.blu.demo1; public class TestJoin implements Runnable{ @Override public void run() { for(int i = 0;i < 1000;i++) { System.out.println("vip线程正在执行....."+i); } } public static void main(String[] args) throws InterruptedException { TestJoin testJoin = new TestJoin(); Thread thread = new Thread(testJoin); thread.start(); for(int i = 0;i < 1000;i++) { if(i==200) { thread.join(); } System.out.println("main线程正在执行....."+i); } } } 

getState()监测线程状态:

返回枚举类型:

NEW RUNNABLE BLOCKED
WAITING
TIMED_WAITING
TERMINATED 

线程优先级:

线程优先级用1-10之间的整数表示,1为最低优先级,10为最高优先级

主线程优先级默认为5,且不可修改

枚举
Thread.MAX_PRIORITY = 10
Thread.NORM_PRIORITY = 5
Thread.MIN_PRIORITY = 1

优先级高不一定先执行,由CPU调度决定

public class TestPriority { public static void main(String[] args) { //主线程优先级 System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority()); MyPriority myPriority = new MyPriority(); Thread t1 = new Thread(myPriority); Thread t2 = new Thread(myPriority); Thread t3 = new Thread(myPriority); Thread t4 = new Thread(myPriority); Thread t5 = new Thread(myPriority); Thread t6 = new Thread(myPriority); //设置优先级 t1.start(); t2.setPriority(1); t3.setPriority(4); t4.setPriority(Thread.MAX_PRIORITY); t5.setPriority(5); t6.setPriority(7); t2.start(); t3.start(); t4.start(); t5.start(); t6.start(); } } class MyPriority implements Runnable{ @Override public void run() { System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority()); } } 

守护线程

线程分为用户线程(比如main)守护线程(比如gc)

虚拟机必须确保用户线程执行完毕,不用等待守护线程执行完毕

当只剩下守护线程时,JVM就会退出,只要存在一个用户线程,JVM就不会退出

public class TestDaemon { public static void main(String[] args) { God god = new God(); You you = new You(); Thread thread = new Thread(god); thread.setDaemon(true); thread.start(); new Thread(you).start(); } } class God implements Runnable{ @Override public void run() { while(true) { System.out.println("上帝保佑着你"); } } } class You implements Runnable{ @Override public void run() { for(int i = 0;i<=100;i++) { System.out.println("你开心地活了"+i+"年"); } System.out.println("GoodBye,World!"); } } 

本文地址:https://blog.csdn.net/BLU_111/article/details/108257513

相关标签: java 多线程