相信很多开发过程中都用过RequestContextHolder.getRequestAttributes()，没错，我也经常用，但今天出现了问题，获取到的实例是空的
原因是因为我新开了一个子线程，在子线程调用了RequestContextHolder.getRequestAttributes()。实际获取到的是空的
然后查看了源码
ThreadLocal获取。一个请求到达容器后，Spring会把该请求Request实例通过setRequestAttributes方法 把Request实例放入该请求线程内ThreadLocalMap中，然后就可以通过静态方法取到。原理就是ThreadLocal，但ThreadLocal不能让子线程继承ThreadLocalMap信息，可以使用InherbritableThreadLocal实现子线程信息传递。
Spring Boot 默认使用ThreadLocal把Request设置进请求线程中，这样如果在请求方法里面另起一个子线程然后再通过getRequestAttributes方法获取，是获取不到的
如果想要在子线程获取,设置inheritable=true即可，但我一直没找到在哪里可以设置，于是自己就写了个工具类来让子线程获取，思路是自定义一个注解，拦截注解，将父线程的ServletRequestAttributes给InheritableThreadLocal，然后在子线程即可获取
package com.shinedata.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface RequestInheritableThread {
}AOP
package com.shinedata.aop;
import com.shinedata.util.context.RequestHolder;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.ServletRequestAttributes;
@Aspect
@Component
public class RequestHolderAspect {
@Before("@annotation(com.shinedata.annotation.RequestInheritableThread)")
public void doBefore(JoinPoint joinPoint) {
ServletRequestAttributes servletRequestAttributes = RequestHolder.getServletRequestAttributes();
RequestHolder.setServletRequestAttributes(servletRequestAttributes);
}
@After("@annotation(com.shinedata.annotation.RequestInheritableThread)")
public void doAfter(JoinPoint joinPoint) {
RequestHolder.removeServletRequestAttributes();
}
}工具类
package com.shinedata.util.context;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;
public class RequestHolder {
private static final Logger logger = LoggerFactory.getLogger(RequestHolder.class);
public static final String GET = "GET";
public static final String POST = "POST";
public static final String UTF8 = "UTF-8";
public static InheritableThreadLocal<ServletRequestAttributes> servletRequestAttributesInheritableThreadLocal= new InheritableThreadLocal();
public static HttpServletRequest getRequest() {
return getServletRequestAttributes().getRequest();
}
public static HttpServletResponse getResponse() {
return getServletRequestAttributes().getResponse();
}
public static ServletRequestAttributes setServletRequestAttributes(ServletRequestAttributes servletRequestAttributes) {
servletRequestAttributesInheritableThreadLocal.set(servletRequestAttributes);
return servletRequestAttributes;
}
public static void removeServletRequestAttributes() {
servletRequestAttributesInheritableThreadLocal.remove();
}
public static ServletRequestAttributes getServletRequestAttributes() {
ServletRequestAttributes requestAttributes = (ServletRequestAttributes)RequestContextHolder.getRequestAttributes();
if(requestAttributes==null){
requestAttributes=servletRequestAttributesInheritableThreadLocal.get();
}
return requestAttributes;
}
}需要在子线程获取ServletRequestAttributes使用的时候在父方法贴个注解@RequestInheritableThread就行了，父方法里面即使开子线程，子线程里面也能获取ServletRequestAttributes
补充第二种解决办法,在开启新线程之前，将RequestAttributes对象设置为子线程共享
//开启新线程之前，添加代码：
ServletRequestAttributes sra = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
RequestContextHolder.setRequestAttributes(sra, true);到此这篇关于Java子线程调用RequestContextHolder.getRequestAttributes()方法问题详解的文章就介绍到这了,更多相关Java RequestContextHolder.getRequestAttributes()内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
