【Java并发编程的艺术】4.1 线程简介

[4.1.1] 什么是线程

public class MultyThread {
    public static void main(String[] args) {

        ThreadMXBean threadMXBean = ManagementFactory.getThreadMXBean();

        ThreadInfo[] threadInfos = threadMXBean.dumpAllThreads(false, false);

        for (ThreadInfo info : threadInfos) {
            System.out.println(
                    "ThreadId=[" + info.getThreadId() + "], " +
                    "ThreadName=[" + info.getThreadName() + "]");
        }

    }
}

ThreadId=[6], ThreadName=[Monitor Ctrl-Break] 
ThreadId=[5], ThreadName=[Attach Listener]
ThreadId=[4], ThreadName=[Signal Dispatcher] // 负责分发内部事件
ThreadId=[3], ThreadName=[Finalizer] // 负责调用Finalizer方法。
ThreadId=[2], ThreadName=[Reference Handler] // 负责处理引用
ThreadId=[1], ThreadName=[main] // 主线程

[4.1.3] 线程优先级

package com.alisa.multythreads;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

/**
 * 线程优先级
 */
public class Priority {
    private static volatile boolean notStart = true;
    private static volatile boolean notEnd = true;

    public static void main(String[] args) throws InterruptedException {

        List<Job> jobs = new ArrayList<>();

        for (int i = 0; i < 10; i++) {
            int priority = (i > 5 ? Thread.MIN_PRIORITY: Thread.MAX_PRIORITY);

            Job job = new Job(priority);
            Thread thread = new Thread(job);

            thread.setPriority(priority);
            thread.start();

            jobs.add(job);
        }

        notStart = false;

        TimeUnit.SECONDS.sleep(10);

        notEnd = false;

        for (Job job : jobs) {
            System.out.println("job priority = " + job.priority + " ,jobCount= [" + job.jobCount + "]");
        }

    }

    private static class Job implements Runnable {

        private long jobCount = 0;

        private int priority;

        public Job(int priority){
            this.priority = priority;
        }

        @Override
        public void run() {
            while (notStart) {
                Thread.yield();
            }

            while (notEnd) {
                Thread.yield();
                jobCount++;
            }
        }

    }
}

job priority = 10 ,jobCount= [22919301]
job priority = 10 ,jobCount= [22845393]
job priority = 10 ,jobCount= [23392615]
job priority = 10 ,jobCount= [23147693]
job priority = 10 ,jobCount= [24327830]
job priority = 10 ,jobCount= [22514344]
job priority = 1 ,jobCount= [23072747]
job priority = 1 ,jobCount= [22916281]
job priority = 1 ,jobCount= [21717784]
job priority = 1 ,jobCount= [22296746]