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Spring Boot使用ThreadLocal、Inherit

Spring Boot使用ThreadLocal、Inherit

作者: CallMe兵哥 | 来源:发表于2019-05-27 17:52 被阅读0次

    4. 异步情况下使用线程池 InheritableThreadLocal的表现

    在异步时InheritableThreadLocal没有发现异常,现在我们加上线程池,看看最终效果。
    1)增加线程池
    为了尽快看到效果,我们将线程的核心数和最大数都设置为2。

    @Configuration
    //@EnableAsync//开启注解:开启异步支持
    public class ThreadPool {
    
        private static final int CORE_POOL_SIZE = Runtime.getRuntime().availableProcessors() *2;
        private static final int MAX_POOL_SIZE = CORE_POOL_SIZE *4 <256 ? 256 : CORE_POOL_SIZE * 4;
        private static final int KEEP_ALIVE_TIME = 10; //允许线程空闲时间(单位为秒)
        private static final int QUEUE_CAPACITY = 200; // 缓冲队列数
        private static final int AWAIT_TERMINATION = 60;//线程池中任务的等待时间,如果超过这个时候还没有销毁就强制销毁
        private static final Boolean WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN = true;//用来设置线程池关闭的时候等待所有任务都完成再继续销毁其他的Bean
        private static final String THREAD_NAME_PREFIX = "PiceaAsync-Service-"; // 线程池名前缀
    
        /**
         * <p>"@Bean("piceaTaskExecutor"),Bean后面的()内容可以省略
         * 如果省略则使用方法名<p>
         * @author jiangbing.yang
         * @date   2019/3/27 11:07
         * @params
         * @return
         * @throws
         */
    
        @Bean("piceaTaskExecutor")
        public static ThreadPoolTaskExecutorpiceaTaskExecutor () {
            ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
            taskExecutor.setCorePoolSize(2);
            taskExecutor.setMaxPoolSize(2);
            taskExecutor.setKeepAliveSeconds(KEEP_ALIVE_TIME);
            taskExecutor.setQueueCapacity(QUEUE_CAPACITY);
            taskExecutor.setThreadNamePrefix(THREAD_NAME_PREFIX);
            taskExecutor.setWaitForTasksToCompleteOnShutdown(WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN);
            taskExecutor.setAwaitTerminationSeconds(AWAIT_TERMINATION);
            // 线程池对拒绝任务的处理策略
            taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
            // 初始化
            taskExecutor.initialize();
            return taskExecutor;
        }
    }
    

    2)在Service层增加方法
    先增加接口

        void testThreadLocalAsyncThreadPool() throws Exception;
    

    然后增加实现

        @Async("piceaTaskExecutor")
        @Override
        public void testThreadLocalAsyncThreadPool() throws Exception {
            System.out.println("我是Service层处理线程,线程名:" + Thread.currentThread().getName());
            System.out.println(" InheritableThreadLocalUtil保存的值为:" + InheritableThreadLocalUtil.getValue());
            InheritableThreadLocalUtil.remove();
        }
    

    3)在Controller层增加测试方法

        @RequestMapping("/testItlTl")
        public String testInheritableThreadLocalThreadPool() throws Exception {
            System.out.println("我是Controller层处理线程,线程名:" + Thread.currentThread().getName());
            InheritableThreadLocalUtil.setValue("我是:testInheritableThreadLocal");
            System.out.println("这里是处理过程,处理中.........");
            System.out.println(" InheritableThreadLocalUtil保存的值为:" + InheritableThreadLocalUtil.getValue());
            piceaService.testThreadLocalAsyncThreadPool();
            return "testInheritableThreadLocalThreadPool:";
        }
    

    4)测试结果
    浏览器中输入http://localhost:2001/testItlTl
    运行3次,第1次和第2次中发现,可以取到父线程的值,第3次的时间,发现就取不到父线程设置的值。

    Spring-boot-TL-ITLTL.png

    5. 异步情况下使用线程池 TransmittableThreadLocal 的表现

    在异步且使用线程池的情况下,InheritableThreadLocal已经出现问题,现在我们使用TransmittableThreadLocal 看看效果。
    1)修改线程池,使用TTL的包装类
    为了尽快看到效果,我们将线程的核心数和最大数都设置为2。主要是这一段“ TtlExecutors.getTtlExecutor(taskExecutor);”这个是重点,这个是重点,这个是重点。重要的问题说三次。

    @Configuration
    //@EnableAsync//开启注解:开启异步支持
    public class ThreadPool {
    
        private static final int CORE_POOL_SIZE = Runtime.getRuntime().availableProcessors() *2;
        private static final int MAX_POOL_SIZE = CORE_POOL_SIZE *4 <256 ? 256 : CORE_POOL_SIZE * 4;
        private static final int KEEP_ALIVE_TIME = 10; //允许线程空闲时间(单位为秒)
        private static final int QUEUE_CAPACITY = 200; // 缓冲队列数
        private static final int AWAIT_TERMINATION = 60;//线程池中任务的等待时间,如果超过这个时候还没有销毁就强制销毁
        private static final Boolean WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN = true;//用来设置线程池关闭的时候等待所有任务都完成再继续销毁其他的Bean
        private static final String THREAD_NAME_PREFIX = "PiceaAsync-Service-"; // 线程池名前缀
    
        /**
         * <p>"@Bean("piceaTaskExecutor"),Bean后面的()内容可以省略
         * 如果省略则使用方法名<p>
         * @author jiangbing.yang
         * @date   2019/3/27 11:07
         * @params
         * @return
         * @throws
         */
    
        @Bean("piceaTaskExecutor")
        public static Executor piceaTaskExecutor () {
            ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
            taskExecutor.setCorePoolSize(2);
            taskExecutor.setMaxPoolSize(2);
            taskExecutor.setKeepAliveSeconds(KEEP_ALIVE_TIME);
            taskExecutor.setQueueCapacity(QUEUE_CAPACITY);
            taskExecutor.setThreadNamePrefix(THREAD_NAME_PREFIX);
            taskExecutor.setWaitForTasksToCompleteOnShutdown(WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN);
            taskExecutor.setAwaitTerminationSeconds(AWAIT_TERMINATION);
            // 线程池对拒绝任务的处理策略
            taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
            // 初始化
            taskExecutor.initialize();
    //        return taskExecutor;
            return TtlExecutors.getTtlExecutor(taskExecutor);
        }
    }
    

    2)在Service层增加方法
    先增加接口

        void testThreadLocalAsyncThreadPoolTtl() throws Exception;
    

    然后增加实现

        @Async("piceaTaskExecutor")
        @Override
        public void testThreadLocalAsyncThreadPoolTtl() throws Exception {
            System.out.println("我是Service层处理线程,线程名:" + Thread.currentThread().getName());
            System.out.println(" TransmittableThreadLocalUtil:" + TransmittableThreadLocalUtil.getValue());
            TransmittableThreadLocalUtil.remove();
        }
    

    3)在Controller层增加测试方法

        @RequestMapping("/testTtlTl")
        public String testTransmittableThreadLocalThreadPool() throws Exception {
            System.out.println("我是Controller层处理线程,线程名:" + Thread.currentThread().getName());
            TransmittableThreadLocalUtil.setValue("我是:testTransmittableThreadLocalThreadPool");
            System.out.println("这里是处理过程,处理中.........");
            System.out.println(" TransmittableThreadLocalUtil保存的值为:" + TransmittableThreadLocalUtil.getValue());
            piceaService.testThreadLocalAsyncThreadPoolTtl();
            return "testInheritableThreadLocalThreadPool:";
        }
    

    4)测试结果
    浏览器中输入http://localhost:2001/testTtlTl
    运行3次以上,发现在都可以取到父线程的值。

    Spring-boot-TL-TTLTL.png

    6. 三个工具类的方法

    1)ThreadLocalUtil

    public class ThreadLocalUtil {
        public static final ThreadLocal<String> THREAD_LOCAL = new ThreadLocal<>();
        //设置线程需要保存的值
        public static void setValue (String str) {
            THREAD_LOCAL.set(str);
        }
        //获取线程中保存的值
        public static String getValue() {
            return THREAD_LOCAL.get();
        }
        //移除线程中保存的值
        public static void remove() {
            THREAD_LOCAL.remove();
        }
    }
    

    2) InheritableThreadLocalUtil

    public class InheritableThreadLocalUtil {
        public static final InheritableThreadLocal<String> THREAD_LOCAL = new InheritableThreadLocal<>();
        //设置线程需要保存的值
        public static void setValue (String str) {
            THREAD_LOCAL.set(str);
        }
        //获取线程中保存的值
        public static String getValue() {
            return THREAD_LOCAL.get();
        }
        //移除线程中保存的值
        public static void remove() {
            THREAD_LOCAL.remove();
        }
    }
    

    3) TransmittableThreadLocalUtil

    public class TransmittableThreadLocalUtil {
        public static final TransmittableThreadLocal<String> THREAD_LOCAL = new TransmittableThreadLocal<>();
        //设置线程需要保存的值
        public static void setValue (String str) {
            THREAD_LOCAL.set(str);
        }
        //获取线程中保存的值
        public static String getValue() {
            return THREAD_LOCAL.get();
        }
        //移除线程中保存的值
        public static void remove() {
            THREAD_LOCAL.remove();
        }
    }
    

    第一章节请移步
    Spring Boot使用ThreadLocal、InheritableThreadLocal、TransmittableThreadLocal -1

    其它注意

    本文章样例:
    工程名:spring-boot-inheritablethreadlocal
    GitHub:https://github.com/zzyjb/SpringBootLearning

    关于异步服务和线程池请移步

    1. Spring Boot 之异步Web服务

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