Spring任务执行器(TaskExecutor)

Spring任务执行器(TaskExecutor)
    Spring通州任务执行器(TaskExecutor)来实现多线程和并发编程，使用ThreadPoolTaskExecutor
可实现一个基于线程的TaskExecutor，而实际开发中任务一般是非阻塞的，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，并通过在实际执行的Bean的方法中使用@Async注解来声明其是一个异步任务。

实例

1.配置类

package com.wisely.highlight_spring4.ch3.taskexecutor;

import java.util.concurrent.Executor;

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;
@Configuration
@ComponentScan("com.wisely.highlight_spring4.ch3.taskexecutor")
@EnableAsync //1 
public class TaskExecutorConfig implements AsyncConfigurer{//2

   @Override
   public Executor getAsyncExecutor() {//2
       ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
           taskExecutor.setCorePoolSize(5);
           taskExecutor.setMaxPoolSize(10);
           taskExecutor.setQueueCapacity(25);
           taskExecutor.initialize();
           return taskExecutor;
   }

   @Override
   public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
      return null;
   }
}


代码解释
1.利用@EnableAsync注解开启异步任务支持。
2.配置类实现AsyncConfigurer接口并重写getAsyncExecutor方法，并返回一个ThreadPoolTaskExecutor，这样我们就获得了已个基于线程池TaskExecutor.

任务执行类

package com.wisely.highlight_spring4.ch3.taskexecutor;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
@Service
public class AsyncTaskService {
   
   @Async //1
    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));
    }
}


代码解释
1.通过@Async注解表明该方法是个异步方法，如果注解在类级别，则表明该类所以的方法都是异步的，
而这里的方法自动被注入使用ThreadPoolTaskExecutor作为TaskExecutor。

运行

package com.wisely.highlight_spring4.ch3.taskexecutor;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Main {
   
   public static void main(String[] args) {
       AnnotationConfigApplicationContext context =
                   new AnnotationConfigApplicationContext(TaskExecutorConfig.class);
       
       AsyncTaskService asyncTaskService = context.getBean(AsyncTaskService.class);
       
       for(int i =0 ;i<10;i++){
          asyncTaskService.executeAsyncTask(i);
          asyncTaskService.executeAsyncTaskPlus(i);
           }
           context.close();
   }
}

结果是并发执行而不是顺序执行的。