SpringBoot使用多线程注解@async

淩亂°似流年 2023-06-05 05:46 173阅读 0赞

1.主类

import com.cnczsq.mall.elephant.utils.SpringUtils;
    import io.swagger.annotations.Api;
    import io.swagger.annotations.ApiOperation;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.scheduling.annotation.Async;
    import org.springframework.transaction.annotation.Transactional;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    /**
     * @author : zhang sq
     * @date : 2019/10/8 11:24
     * SpringBoot注解多线程
     **/
    @RestController
    @RequestMapping("/AsyncTest")
    @Api(value = "注解多线程测试", description = "AsyncTest")
    public class AsyncTest {
        private final Logger log = LoggerFactory.getLogger(this.getClass());
        @Autowired
        private Asyncs asyncs;
    
        @GetMapping("/test")
        @ApiOperation(value = "线程测试")
        @Transactional
        public String test() {
            //直接调用失效,为单线程
            doAsyncMethod();
            doAsyncMethod();
            doAsyncMethod();
            doAsyncMethod();
            doAsyncMethod();
    
            //从写类单独管理 ,注入调用,多线程
            asyncs.doAsyncMethod();
            asyncs.doAsyncMethod();
            asyncs.doAsyncMethod();
            asyncs.doAsyncMethod();
            asyncs.doAsyncMethod();
    
            //内部调用,通过获取bean对象,调用,多线程
            AsyncTest bean = SpringUtils.getBean(AsyncTest.class);
            bean.doAsyncMethod();
            bean.doAsyncMethod();
            bean.doAsyncMethod();
            bean.doAsyncMethod();
            bean.doAsyncMethod();
            log.info("主线程执行结束......");
            return "SUCCESS";
        }
    
        /**
         * @Description //同类方法中的异步标签
         **/
        @Async
        public void doAsyncMethod() {
            try {
                Thread.sleep(2000);
                log.info("2直接调用类异步方法执行了......");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

2.单独管理线程,注入类

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.scheduling.annotation.Async;
    import org.springframework.stereotype.Component;
    /**
     * @author : zhang sq
     * @date : 2019/10/8 11:26
     **/
    @Component
    public class Asyncs {
        private  final Logger log =  LoggerFactory.getLogger(this.getClass());
        @Async
        public void doAsyncMethod() {
            try {
                Thread.sleep(2000);
                log.info("1注入类异步方法执行了......");
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }

3.SpringUtil工具类,获取spring管理bean

import org.springframework.beans.BeansException;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.ApplicationContextAware;
    import org.springframework.stereotype.Component;
    /**
     * @author : zhang sq
     * @date : 2019/8/30 17:17
     **/
    @Component
    public class SpringUtils implements ApplicationContextAware {
    
        private static ApplicationContext applicationContext;
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            if (SpringUtils.applicationContext == null) {
                SpringUtils.applicationContext = applicationContext;
            }
        }
    
        //获取applicationContext
        public static ApplicationContext getApplicationContext() {
            return applicationContext;
        }
    
        //通过name获取 Bean.
        public static Object getBean(String name) {
            return getApplicationContext().getBean(name);
        }
    
        //通过class获取Bean.
        public static <T> T getBean(Class<T> clazz) {
            return getApplicationContext().getBean(clazz);
        }
    
        //通过name,以及Clazz返回指定的Bean
        public static <T> T getBean(String name, Class<T> clazz) {
            return getApplicationContext().getBean(name, clazz);
        }
    }

4.测试结果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nc2hlbmdxaWFuZzE2OA_size_16_color_FFFFFF_t_70][]

结果:直接在类里面调用,为单线程处理@Async 不生效 , 可以使用单独管理线程注入调用,或者获取spring管理的Bean对象,调用,都可以达到异步效果;

常见@Async注解不生效原因:

1.@SpringBootApplication启动类当中没有添加注解@EnableAsync注解。

2.没有走Spring的代理类。因为@Transactional和@Async注解的实现都是基于Spring的AOP，而AOP的实现是基于动态代理模式实现的。那么注解失效的原因就很明显了，有可能因为调用方法的是对象本身而不是代理对象，因为没有经过Spring容器

3.还有一种说法是 异步方法使用注解@Async的返回值只能为void或者Future。我测试好像不存在这个问题(待定)

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nc2hlbmdxaWFuZzE2OA_size_16_color_FFFFFF_t_70]: /images/20230601/84c5e6142079400c8a62cc622c25de24.png