Spring多线程

Spring是通过TaskExecutor任务执行器来实现多线程和并发编程的。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。

（1）配置类

package com.lwh.highlight_spring4.ch3.taskexecutor;

/**
 * Created by luwenhu on 2017/9/20.
 */

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;

/**
 * Spring是通过TaskExecutor任务执行器来实现多线程和并发编程的。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
 */
@Configuration
@ComponentScan("com.lwh.highlight_spring4.ch3.taskexecutor")
@EnableAsync//开启异步任务支持
public class TaskExecutorConfig implements AsyncConfigurer{

    /**
     * 实现AsyncConfigurer并重写getAsyncExecutor方法返回一个ThreadPoolTaskExecutor
     * @return
     */
    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
        threadPoolTaskExecutor.setMaxPoolSize(10);
        threadPoolTaskExecutor.setCorePoolSize(5);
        threadPoolTaskExecutor.setQueueCapacity(25);
        threadPoolTaskExecutor.initialize();
        return threadPoolTaskExecutor;
    }

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

（2）任务执行类

package com.lwh.highlight_spring4.ch3.taskexecutor;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

/**
 * Created by luwenhu on 2017/9/20.
 */
@Service
public class AsyncTaskService {

    @Async//通过@Async注解表明该方法是个异步方法，如果注解在类级别，则表明该类所有的方法都是异步方法，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）运行类

package com.lwh.highlight_spring4.ch3.taskexecutor;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * Created by luwenhu on 2017/9/20.
 */
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();
    }
}

运行结果：