java.lang.IllegalStateException: No thread-bound request found 解决方法

1、让我们看看这熟悉的报错

java.lang.IllegalStateException: No thread-bound request found: 
Are you referring to request attributes outside of an actual web request, 
or processing a request outside of the originally receiving thread? 
If you are actually operating within a web request and still receive this message, 
your code is probably running outside of DispatcherServlet: In this case, 
use RequestContextListener or RequestContextFilter to expose the current request.

2、我的使用场景

在@Async注解的方法里进行Feign调用，为什么会出现这个问题尼？是因为我@configurtion里加了这行代码，因为有业务需求我要从request里取到header里的参数

HttpServletRequest request = ((ServletRequestAttributes) 
(RequestContextHolder.currentRequestAttributes())).getRequest();

3、那这个报错信息从何而来？

点进RequestContextHolder这个类，查看源码可知，RequestAttributes - 请求属性线程拿不到了，所以为null，然后就throw new IllegalStateException，以下为源码：

	/**
	 * Return the RequestAttributes currently bound to the thread.
	 * 
Exposes the previously bound RequestAttributes instance, if any.
	 * Falls back to the current JSF FacesContext, if any.
	 * @return the RequestAttributes currently bound to the thread
	 * @throws IllegalStateException if no RequestAttributes object
	 * is bound to the current thread
	 * @see #setRequestAttributes
	 * @see ServletRequestAttributes
	 * @see FacesRequestAttributes
	 * @see javax.faces.context.FacesContext#getCurrentInstance()
	 */
	public static RequestAttributes currentRequestAttributes() throws IllegalStateException {
		RequestAttributes attributes = getRequestAttributes();
		if (attributes == null) {
			if (jsfPresent) {
				attributes = FacesRequestAttributesFactory.getFacesRequestAttributes();
			}
			if (attributes == null) {
				throw new IllegalStateException("No thread-bound request found: " +
						"Are you referring to request attributes outside of an actual web request, " +
						"or processing a request outside of the originally receiving thread? " +
						"If you are actually operating within a web request and still receive this message, " +
						"your code is probably running outside of DispatcherServlet: " +
						"In this case, use RequestContextListener or RequestContextFilter to expose the current request.");
			}
		}
		return attributes;
	}

4、解决方法

只需要在调用异步方法的外面将RequestAttributes对象设置为子线程共享即可。当然，我们要知道异步线程执行时，ThreadLocal - 线程上下文信息不会自动带过去。当然还有InheritableThreadLocal可以支持将线程上下文传入子线程。

4.2、核心代码

ServletRequestAttributes sra = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
RequestContextHolder.setRequestAttributes(sra, true);

4.3、举个栗子

public void childThreadSharing(ScreeningDTO dto) {
	// 设置子线程共享
	ServletRequestAttributes sra = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    RequestContextHolder.setRequestAttributes(sra, true);
	// 开始执行异步方法
	this.somethingService.executeAsync();
}