Java Springboot 线程池使用

我会带着你远行 2023-10-04 11:50 39阅读 0赞

## Java Springboot 线程池使用 ##

**一、基本概念**

1.进程：一个程序的执行，包含多个线程  
2.线程：一个程序执行中的片段但，进程执行中的最小单位  
3.使用场景：  
①后台任务：定时发送大量邮件  
②异步处理：统计、日志  
③分布式计算、分片下载、断点续传  
4.用户线程和守护线程  
用户线程：程序本身执行的线程  
守护线程：为程序提供通用服务的线程（GC 垃圾回收线程）  
用户线程存在，JVM不会离开；用户线程执行完成退出，无论守护线程是否存在，JVM都将离开  
5.同一CPU内核，同一时间，只能执行一个线程  
线程调度器，分配时间片  
线程优先级分为10级，1最低，10最高  
6.线程的停止：采用中断  
7.线程的状态：  
①NEW  
②RUNNABLE  
③BLOCKED  
④WAITING  
⑤TIMED\_WAITING  
⑥TERMINATED  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjE3NjYzOQ_size_16_color_FFFFFF_t_70]  
8.控制线程执行顺序：join方法（优先级是提高概率，并不绝对）  
9.线程安全：子线程访问共享变量，共享变量在主内存中，访问时会将共享变量拷贝至自己的工作内存，操作完成后再写回主变量  
10.Java并发编程三大特性：原子性、可见性、有序性

**二、线程演示**  
1.线程创建

package com.atguigu.thread;
    
    import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.concurrent.Callable;
    import java.util.concurrent.ExecutionException;
    import java.util.concurrent.FutureTask;
    
    /**
     * Description: 多线程Demo
     *
     * @Author: 
     * @Date: 2021-04-25 20:53
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadDemo {
        
    
        private static int num=10;
    
        public static void main(String[] args) {
        
    
            /**
             * 采用继承的方式，只能单继承Thread
             * 采用实现接口的方式，可以在实现接口的基础上再进行一次继承
             * 同时，采用接口的写法可以改为匿名内部类的方式，进一步简化为Lambda表达式形式
             */
    
            TestThread testThread = new TestThread();
            testThread.start();
    
            Thread thread = new Thread(new TestRunnable());
            thread.start();
    
            Thread threadN = new Thread(new Runnable(){
        
                @Override
                public void run(){
        
                    log.info("匿名内部类形式");
                }
            });
            threadN.start();
    
            Thread threadL = new Thread(()->{
        
                log.info("Lambda表达式形式");
            });
            threadL.start();
    
            /**
             * 带返回值的线程
             */
            FutureTask<Integer> futureTask = new FutureTask<>(new TestCallable());
            Thread threadRet = new Thread(futureTask);
            threadRet.start();
            try {
        
                //得到线程执行处理结果
                Integer result = futureTask.get();
                log.info("得到线程执行处理结果:{}",result);
            }catch (ExecutionException exception) {
        
                log.error("",exception);
            }catch (InterruptedException exception) {
        
                log.error("",exception);
            }
    
        }
    
        /**
         * 继承Thead类，实现Run方法
         */
        static class TestThread extends Thread{
        
            @Override
            public void run(){
        
                for (int i=0;i<num;i++){
        
                    log.info("Print 【{}】 Times",i);
                }
            }
        }
    
        /**
         * 实现Runnable接口，实现Run方法
         */
        static class TestRunnable implements Runnable{
        
    
            @Override
            public void run() {
        
                for (int i=0;i<num;i++){
        
                    log.info("Print 【{}】 Times",i);
                }
            }
        }
    
        /**
         * 实现Callable接口，实现带返回值的任务
         */
        static class TestCallable implements Callable<Integer>{
        
    
            @Override
            public Integer call() throws Exception {
        
                int sum=0;
                for (int i=0;i<num;i++){
        
                    log.info("Print 【{}】 Times",i);
                    sum+=i;
                }
                return sum;
            }
        }
    
    }

2.线程停止

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 线程停止的方法
     *
     * @Author: 
     * @Date: 2021-04-25 21:47
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadStopDemo {
        
    
    
        /**
         * 优雅的终止线程
         * threadTest.interrupt() 中断线程
         * Thread.currentThread().isInterrupted() 线程是否中断
         * @param args
         */
        public static void main(String[] args) {
        
    
            Thread threadTest = new Thread(()->{
        
                while (true){
        
                    if(Thread.currentThread().isInterrupted()){
        
                        break;
                    }
                    log.info("线程执行中......");
                }
            });
            threadTest.start();
            /**
             * 主线程休眠2秒
             * 然后将子线程中断
             */
            try {
        
                Thread.sleep(2000);
                threadTest.interrupt();
            } catch (InterruptedException interruptedException) {
        
                interruptedException.printStackTrace();
            }
        }
    }

3.用户线程和守护线程

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 用户线程和守护线程测试
     *
     * @Author: 
     * @Date: 2021-04-25 21:27
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadDaemonDemo {
        
    
        private static int num = 100;
    
        /**
         * new Thread 默认为非守护进程
         * 设置为守护进程后，当threadUser执行完成时，threadDaemon立即结束
         * @param args
         */
        public static void main(String[] args) {
        
    
            /**
             * 守护线程
             */
    
            Thread threadDaemon = new Thread(()->{
        
                for (int i=0;i<num;i++){
        
                    try {
        
                        Thread.sleep(200);
                        log.info("守护线程：【{}】",i);
                    } catch (InterruptedException interruptedException) {
        
                        interruptedException.printStackTrace();
                    }
                }
            });
            threadDaemon.setDaemon(false);
            threadDaemon.start();
    
            /**
             * 用户线程
             */
    
            Thread threadUser = new Thread(()->{
        
                for (int i=0;i<num;i++){
        
                    try {
        
                        Thread.sleep(50);
                        log.info("用户线程：【{}】",i);
                    } catch (InterruptedException interruptedException) {
        
                        interruptedException.printStackTrace();
                    }
                }
            });
            threadUser.start();
        }
    }

4.线程优先级

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 线程优先级测试
     *
     * @Author: 
     * @Date: 2021-04-25 21:36
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadPriority {
        
    
        private static int num = 100;
    
        /**
         * 设置优先级1-10 默认为5
         * @param args
         */
        public static void main(String[] args) {
        
    
            /**
             * 守护线程
             */
    
            Thread threadFirst = new Thread(()->{
        
                for (int i=0;i<num;i++){
        
                    log.info("线程1：【{}】",i);
                }
            });
            threadFirst.setPriority(1);
            threadFirst.start();
    
            /**
             * 用户线程
             */
    
            Thread threadSecond = new Thread(()->{
        
                for (int i=0;i<num;i++){
        
                    log.info("线程2：【{}】",i);
                }
            });
            threadSecond.setPriority(10);
            threadSecond.start();
        }
    }

5.线程顺序执行

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 线程执行顺序
     *
     * @Author: 
     * @Date: 2021-04-25 22:22
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadJoin {
        
    
        private static int num = 100;
    
        /***
         * 控制线程T1、T2、T3按顺序执行
         * join A { B.join() } 则A会在B执行完后执行
         * @param args
         */
        public static void main(String[] args) {
        
    
            Thread t1 = new Thread(()->{
        
                for (int i=0;i<num;i++){
        
                    log.info("线程0：【{}】",i);
                }
            });
    
            Thread t2 = new Thread(()->{
        
                try {
        
                    t1.join();
                } catch (InterruptedException interruptedException) {
        
                    interruptedException.printStackTrace();
                }
                for (int i=0;i<num;i++){
        
                    log.info("线程1：【{}】",i);
                }
            });
    
            Thread t3 = new Thread(()->{
        
                try {
        
                    t2.join();
                } catch (InterruptedException interruptedException) {
        
                    interruptedException.printStackTrace();
                }
                for (int i=0;i<num;i++){
        
                    log.info("线程2：【{}】",i);
                }
            });
            t1.start();
            t2.start();
            t3.start();
        }
    }

6.线程安全与锁（不加锁则会出现卖票混乱）

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 线程安全测试
     *
     * @Author: 
     * @Date: 2021-04-25 22:53
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadSafeDemo {
        
    
        private static int tickets=100;
    
        public static void main(String[] args) {
        
            Object o = new Object();
            Runnable runnable = ()->{
        
                while (true){
        
                    try {
        
                        Thread.sleep(1);
                    } catch (InterruptedException interruptedException) {
        
                        interruptedException.printStackTrace();
                    }
                    synchronized (o){
        
                        if(tickets>0){
        
                            tickets--;
                            log.info("{} 卖了一张票，剩余 {}",Thread.currentThread().getName(),tickets);
                        }else{
        
                            break;
                        }
                    }
                }
            };
    
            Thread t1 = new Thread(runnable,"窗口1");
            Thread t2 = new Thread(runnable,"窗口2");
            Thread t3 = new Thread(runnable,"窗口3");
            t1.start();
            t2.start();
            t3.start();
    
        }
    }

7.线程通信演示 等待wait和唤醒notify

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    /**
     * Description: 线程通信演示 等待：wait 唤醒：notify
     *
     * @Author: 
     * @Date: 2021-04-28 23:34
     * @version: V1.0.0
     */
    @Slf4j
    public class ThreadCommunication {
        
    
        public static void main(String[] args) {
        
    
            NumMode  numMode = new NumMode();
    
            /**
             * 奇数情况输出
             */
            new Thread(()->{
        
                while (true){
        
                    synchronized (numMode){
        
                        if(numMode.num<100){
        
                            if(numMode.num%2!=0){
        
                                log.info("奇数打印：{}",numMode.num);
                                numMode.num++;
                                numMode.notify();
                            }else{
        
                                try {
        
                                    numMode.wait();
                                } catch (InterruptedException interruptedException) {
        
                                    interruptedException.printStackTrace();
                                }
                            }
                        }else {
        
                            break;
                        }
                    }
                }
            }).start();
    
            /**
             * 偶数情况输出
             */
            new Thread(()->{
        
                while (true){
        
                    synchronized (numMode){
        
                        if(numMode.num<100){
        
                            if(numMode.num%2==0){
        
                                log.info("偶数打印：{}",numMode.num);
                                numMode.num++;
                                numMode.notify();
                            }else{
        
                                try {
        
                                    numMode.wait();
                                } catch (InterruptedException interruptedException) {
        
                                    interruptedException.printStackTrace();
                                }
                            }
                        }else {
        
                            break;
                        }
                    }
                }
            }).start();
        }
    
        static class NumMode{
        
            int num=0;
        }
    }

8.消费和生产者模型演示 等待wait和唤醒notify

package com.atguigu.thread;
    
    import lombok.extern.slf4j.Slf4j;
    
    import java.util.LinkedList;
    
    /**
     * Description: 生产者消费者模型
     *
     * 生产者：做手机
     * 消费者：买手机
     * 手机店：库存容量30台
     *
     * @Author: 
     * @Date: 2021-04-28 23:57
     * @version: V1.0.0
     */
    @Slf4j
    public class ProductionAndConsumption {
        
    
        static int version = 1;
    
        /**
         * 顾客
         */
        static class CustomerTask implements Runnable{
        
            MobileShop mobileShop;
            public CustomerTask(MobileShop mobileShop) {
        
                this.mobileShop = mobileShop;
            }
    
            @Override
            public void run() {
        
                while (true){
        
                    synchronized (mobileShop){
        
                        if(mobileShop.phoneList.size()>0){
        
                            mobileShop.phoneList.poll();
                            mobileShop.notifyAll();
                            log.info(":{}购买了一台手机",Thread.currentThread().getName());
                        }else{
        
                            //手机抢光了
                            try {
        
                                mobileShop.wait();
                            } catch (InterruptedException interruptedException) {
        
                                interruptedException.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
    
        /**
         * 山寨手机厂
         */
        static class ProductTask implements Runnable{
        
    
            MobileShop mobileShop;
            public ProductTask(MobileShop mobileShop) {
        
                this.mobileShop = mobileShop;
            }
    
            @Override
            public void run() {
        
                while (true){
        
                    synchronized (mobileShop){
        
                        if(mobileShop.phoneList.size()<30){
        
                            Phone phone = new Phone();
                            phone.setModel("小米"+version);
                            version++;
                            mobileShop.phoneList.push(phone);
                            mobileShop.notifyAll();
                            log.info("{}:生产了一台手机，共{}版本了",Thread.currentThread().getName(),version);
                        }else{
        
                            //库存已满，停止生产
                            try {
        
                                mobileShop.wait();
                            } catch (InterruptedException interruptedException) {
        
                                interruptedException.printStackTrace();
                            }
                        }
                    }
                }
            }
        }
    
        /**
         * 手机店
         */
        static class MobileShop{
        
            LinkedList phoneList = new LinkedList();
        }
    
        /**
         * 手机
         */
        static class Phone{
        
            String model;
            public void setModel(String model) {
        
                this.model = model;
            }
            public String getModel() {
        
                return model;
            }
    
        }
    
        public static void main(String[] args) {
        
            MobileShop mobileShop = new MobileShop();
            new Thread(new ProductTask(mobileShop)).start();
            new Thread(new CustomerTask(mobileShop)).start();
            new Thread(new CustomerTask(mobileShop)).start();
    
    
        }
    }

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