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解決Springboot中@Async注解獲取不到上下文信息問(wèn)題

更新時(shí)間：2024年01月15日 11:49:46 作者：飛翔的佩奇

實(shí)際開(kāi)發(fā)中我們經(jīng)常需要通過(guò)spring上下文獲取一些配置信息,本文主要介紹了解決Springboot中@Async注解獲取不到上下文信息問(wèn)題,具有一定的參考價(jià)值,感興趣的可以了解一下

問(wèn)題描述

springboot項(xiàng)目中，需要使用到異步調(diào)用某個(gè)方法，此時(shí) 第一個(gè)想到的就是 @Async 注解，但是發(fā)現(xiàn) 方法執(zhí)行報(bào)錯(cuò)了，具體報(bào)錯(cuò)如下：

java.lang.NullPointerException
   at com.ruoyi.common.utils.ServletUtils.getRequest(ServletUtils.java:56)
   at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:782)
   at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:717)
   at org.springframework.web.client.RestTemplate.postForObject(RestTemplate.java:443)
   at com.ruoyi.web.ecs.service.impl.EcsCollectOperateServiceImpl.collect(EcsCollectOperateServiceImpl.java:42)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:90)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
   at java.lang.reflect.Method.invoke(Method.java:508)
   at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
   at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115)
   at java.util.concurrent.FutureTask.run(FutureTask.java:277)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1160)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
   at java.lang.Thread.run(Thread.java:825)

上面日志有點(diǎn)多，其實(shí)核心就是這一部分日志：

java.lang.NullPointerException
at com.ruoyi.common.utils.ServletUtils.getRequest(ServletUtils.java:56)

這塊邏輯就是，使用spring底層提供的獲取上下文信息的方法。
所以說(shuō)明獲取不到上下文信息，結(jié)果導(dǎo)致報(bào)錯(cuò)

解決辦法

對(duì)自定義的配置類進(jìn)行改造，原來(lái)的配置類是這樣的：

import java.lang.reflect.Method;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

@Configuration
@EnableAsync
public class AsyncConfiguration {

	private static final Logger logger = LoggerFactory.getLogger(AsyncConfiguration.class);

	@Bean(name = "taskExecutor")
	public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();

        // 核心線程數(shù)：線程池創(chuàng)建時(shí)候初始化的線程數(shù)
        taskExecutor.setCorePoolSize(10);

        // 最大線程數(shù)：線程池最大的線程數(shù)，只有在緩沖隊(duì)列滿了之后才會(huì)申請(qǐng)超過(guò)核心線程數(shù)的線程
        taskExecutor.setMaxPoolSize(20);

        // 緩沖隊(duì)列：用來(lái)緩沖執(zhí)行任務(wù)的隊(duì)列
        taskExecutor.setQueueCapacity(50);

        // 允許線程的空閑時(shí)間60秒：當(dāng)超過(guò)了核心線程之外的線程在空閑時(shí)間到達(dá)之后會(huì)被銷毀
        taskExecutor.setKeepAliveSeconds(60);

        // 線程池名的前綴：設(shè)置好了之后可以方便我們定位處理任務(wù)所在的線程池
        taskExecutor.setThreadNamePrefix("HiTask-");

        // 緩沖隊(duì)列滿了之后的拒絕策略：由調(diào)用線程處理（一般是主線程）
        //taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
        taskExecutor.initialize();

        return taskExecutor;
    }



	class MyAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {

		@Override
		public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
			logger.error("MethodName={},Throwable={}",method.getName(),throwable.toString());
		}
	}
}

改造之后：

import java.lang.reflect.Method;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;

@Configuration
@EnableAsync
public class AsyncConfiguration {

	private static final Logger logger = LoggerFactory.getLogger(AsyncConfiguration.class);

	@Bean(name = "taskExecutor")
	public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();

        // 核心線程數(shù)：線程池創(chuàng)建時(shí)候初始化的線程數(shù)
        taskExecutor.setCorePoolSize(10);

        // 最大線程數(shù)：線程池最大的線程數(shù)，只有在緩沖隊(duì)列滿了之后才會(huì)申請(qǐng)超過(guò)核心線程數(shù)的線程
        taskExecutor.setMaxPoolSize(20);

        // 緩沖隊(duì)列：用來(lái)緩沖執(zhí)行任務(wù)的隊(duì)列
        taskExecutor.setQueueCapacity(50);

        // 允許線程的空閑時(shí)間60秒：當(dāng)超過(guò)了核心線程之外的線程在空閑時(shí)間到達(dá)之后會(huì)被銷毀
        taskExecutor.setKeepAliveSeconds(60);

        // 線程池名的前綴：設(shè)置好了之后可以方便我們定位處理任務(wù)所在的線程池
        taskExecutor.setThreadNamePrefix("HiTask-");

        // 緩沖隊(duì)列滿了之后的拒絕策略：由調(diào)用線程處理（一般是主線程）
        //taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
        taskExecutor.initialize();

        //解決使用@Async注解，獲取不到上下文信息的問(wèn)題
        taskExecutor.setTaskDecorator(runnable -> {
            RequestAttributes requestAttributes = RequestContextHolder.currentRequestAttributes();
            return ()->{
                try {
                    // 我們set 進(jìn)去 ,其實(shí)是一個(gè)ThreadLocal維護(hù)的.
                    RequestContextHolder.setRequestAttributes(requestAttributes);
                    runnable.run();
                } finally {
                    // 最后記得釋放內(nèi)存
                    RequestContextHolder.resetRequestAttributes();
                }
            };

        });

        return taskExecutor;
    }



	class MyAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {

		@Override
		public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
			logger.error("MethodName={},Throwable={}",method.getName(),throwable.toString());
		}
	}
}

總結(jié)

解決使用@Async注解，獲取不到上下文信息的問(wèn)題，只需要增加這一段代碼即可

 taskExecutor.setTaskDecorator(runnable -> {
            RequestAttributes requestAttributes = RequestContextHolder.currentRequestAttributes();
            return ()->{
                try {
                    // 我們set 進(jìn)去 ,其實(shí)是一個(gè)ThreadLocal維護(hù)的.
                    RequestContextHolder.setRequestAttributes(requestAttributes);
                    runnable.run();
                } finally {
                    // 最后記得釋放內(nèi)存
                    RequestContextHolder.resetRequestAttributes();
                }
            };

        });

額外補(bǔ)充一點(diǎn)

如果使用 @Async注解，發(fā)現(xiàn)沒(méi)有生效，那有可能你沒(méi)有加 @EnableAsync 注解。
@EnableAsync注解表示開(kāi)啟異步任務(wù)，可以寫(xiě)在springboot的啟動(dòng)類上，也可以寫(xiě)在配置類上

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