一、多线程
Springt通过任务执行器(TaskExecutor)来实现多线程和并发编程。使用ThreadPoolTaskExecutor可实现一个基于线程池的TaskExecutor。而实际开发中任务一般是非阻碍的,即异步的,所以我们要在配置类中通过@EnableAsync 开启对异步任务的支持,并通过实际执行Bean的方法中使用@Async注解来声明其是一个异步任务。
示例:
1.配置类。
package com.ecworking.async; import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.scheduling.annotation.AsyncConfigurer; import org.springframework.scheduling.annotation.EnableAsync; import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; import java.util.concurrent.Executor; @Configuration @ComponentScan("com.ecworking.async") @EnableAsync // 利用@EnableAsync注解开启异步任务支持 public class AsyncTaskConfig implements AsyncConfigurer{ @Override public Executor getAsyncExecutor() { // 配置类实现AsyncConfigurer接口并重写 getAsyncExecutor 方法,并返回一个 ThreadPoolTaskExecutor,这样我们就获得了一个线程池 taskExecutor ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor(); taskExecutor.setCorePoolSize(5); taskExecutor.setMaxPoolSize(10); taskExecutor.setQueueCapacity(25); taskExecutor.initialize(); return taskExecutor; } @Override public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() { return null; } }
2.任务执行类
package com.ecworking.async; import org.springframework.scheduling.annotation.Async; import org.springframework.stereotype.Service; @Service public class AsyncTaskService { @Async // 通过@Async注解表明该方法是一个异步方法,如果注解在类级别,表明该类下所有方法都是异步方法,而这里的方法自动被注入使用ThreadPoolTaskExecutor 作为 TaskExecutor public void executeAsyncTask(Integer i){ System.out.println("执行异步任务:" + i); } @Async public void executeAsyncTaskPlus(Integer i){ System.out.println("执行异步任务+1:" + (i+1)); } }
3.运行
package com.ecworking.async; import org.springframework.context.annotation.AnnotationConfigApplicationContext; public class Mian { public static void main(String[] args){ AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AsyncTaskConfig.class); AsyncTaskService asyncTaskService = context.getBean(AsyncTaskService.class); for(int i = 0; i < 10; i++){ asyncTaskService.executeAsyncTask(i); asyncTaskService.executeAsyncTaskPlus(i); } } }
运行结果是并发执行而不是顺序执行