介绍在SpringBoot项目中,使用@Async不生效的原因介绍和分析;
代码参考gitee仓库:spring-boot-2022-05: 主要是介绍Spring框架注解、常用的功能的使用案例,记录平时遇到的技术知识点,进行实践操作; - Gitee.com
一、常见原因:
1.启动类中没有添加注解@EnableAsync;
2.同一个类中调用含有@Async的方法;因为@Transactional和@Async是采用Spring AOP原理实现的,需要通过代理对象调用其方法。
3.方法必须是public修饰,且返回值是void或Future。
4.使用ThreadPoolTaskExecutor对象创建自定义线程池?
5.关于@Async("param")中参数param含义?
正确使用步骤事项:
第一步:启动类中应该添加注解@EnableAsync;
第二步:执行方法和异步方法不在同一个类中。
第三步:异步方法必须是public 修饰,且返回值是void或Future;
二、具体案例:
1.启动类需要添加注解@EnableAsync
package com.dbzhang;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;
/**
* @program: spring-boot-2022-05
* @description:
* @author: zdb
* @motto: 认真写好每一行代码
* @create: 2022-05-05 13:15
*/
@SpringBootApplication
@EnableAsync
public class ApplicationRun {
public static void main(String[] args) {
SpringApplication.run(ApplicationRun.class, args);
}
}
2.PlayerService业务类:通过代理对象调用异步方法发送短信asyncMethodClass.sendMessage(playerId, msg);
package com.dbzhang.asyc;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
/**
* @program: spring-boot-2022-05
* @description:
* @author: zdb
* @motto: 认真写好每一行代码
* @create: 2022-10-18 13:11
*/
@Component
@Slf4j
public class PlayerService {
@Resource
private AsyncMethodClass asyncMethodClass;
public void register(Long playerId) {
log.info("begin----注册用户编号,playerId:{}", playerId);
//异步发送短信
String msg = "异步发送短信";
asyncMethodClass.sendMessage(playerId, msg);
log.info("end----注册用户编号,playerId:{}", playerId);
}
}
3.AsyncMethodClass中异步方法,使用@Async("param")标记异步方法,其中param参数是引用线程池的bean名称,但是Spring容器中必须存在这个bean。
package com.dbzhang.asyc;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;
/**
* @program: spring-boot-2022-05
* @description:
* @author: zdb
* @motto: 认真写好每一行代码
* @create: 2022-10-18 13:12
*/
@Component
@Slf4j
public class AsyncMethodClass {
/**
* 测试调用异常方法:发送短信
*
*/
@Async("threadPoolTaskExecutor")
public void sendMessage(Long playerId, String msg) {
log.info("玩家注册编号playerId:{},发送短信信息msg:{}", playerId, msg);
}
}
4.自定义线程池ThreadPoolTaskExector,并交给Spring容器管理。
package com.dbzhang.asyc;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
/**
* @program: spring-boot-2022-05
* @description: 自定义线程池配置
* @author: zdb
* @motto: 认真写好每一行代码
* @create: 2022-10-19 12:50
*/
@Configuration
public class AsyncThreadParam {
@Value("${threadPool.corePoolSize}")
private int corePoolSize;
@Value("${threadPool.maxPoolSize}")
private int maxPoolSize;
@Value("${threadPool.keepAliveSeconds}")
private int keepAliveSeconds;
@Value("${threadPool.queueCapacity}")
private int queueCapacity;
@Value("${threadPool.namePrefix}")
private String namePrefix;
/**
* 初始化线程池参数
*
* @return
*/
@Bean(value = "threadPoolTaskExecutor")
public ThreadPoolTaskExecutor initThreadPoolTaskExecutor() {
ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
threadPoolTaskExecutor.setCorePoolSize(corePoolSize);
threadPoolTaskExecutor.setMaxPoolSize(maxPoolSize);
threadPoolTaskExecutor.setQueueCapacity(queueCapacity);
threadPoolTaskExecutor.setKeepAliveSeconds(keepAliveSeconds);
threadPoolTaskExecutor.setThreadNamePrefix(namePrefix);
// threadPoolTaskExecutor.setRejectedExecutionHandler();
return threadPoolTaskExecutor;
}
}
5.配置文件中执行线程参数:
#自定义线程池ThreadPoolTaskExecutor参数
threadPool:
corePoolSize: 2
maxPoolSize: 5
keepAliveSeconds: 60
queueCapacity: 10
namePrefix: async-zdb-
6.测试类:
package com.dbzhang.async;
import com.dbzhang.asyc.PlayerService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
/**
* @program: spring-boot-2022-05
* @description:
* @author: zdb
* @motto: 认真写好每一行代码
* @create: 2022-10-18 13:18
*/
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class AsyncTest {
@Autowired
private PlayerService playerService;
@Test
public void testAsync() {
playerService.register(123456789L);
}
}
7.执行结果:
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