spring HttpServletRequest 简介

前提：工作遇到controller中通过注解的方式注入

@Resource
private HttpServletRequest request;

我们都知道spring 默认是单例，当遇到并发的时候线程不安全，但是经过测试它安全的。

综上，确定spring肯定对它做了处理，因此打开我的探索之路.....

上源码

public class RequestContextListener implements ServletRequestListener {
    private static final String REQUEST_ATTRIBUTES_ATTRIBUTE = RequestContextListener.class.getName() + ".REQUEST_ATTRIBUTES";

    public RequestContextListener() {
    }

    public void requestInitialized(ServletRequestEvent requestEvent) {
        if(!(requestEvent.getServletRequest() instanceof HttpServletRequest)) {
            throw new IllegalArgumentException("Request is not an HttpServletRequest: " + requestEvent.getServletRequest());
        } else {
            HttpServletRequest request = (HttpServletRequest)requestEvent.getServletRequest();
            ServletRequestAttributes attributes = new ServletRequestAttributes(request);
            request.setAttribute(REQUEST_ATTRIBUTES_ATTRIBUTE, attributes);
            LocaleContextHolder.setLocale(request.getLocale());
　　　　　　　　//放到这里了，RequestContextHolder下的requestAttributes让我们跟进去瞅瞅
            RequestContextHolder.setRequestAttributes(attributes);
        }
    }

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public abstract class RequestContextHolder {
    private static final boolean jsfPresent = ClassUtils.isPresent("javax.faces.context.FacesContext", RequestContextHolder.class.getClassLoader());
　　//原来如此啊，是通过threadLocal去保证的
    private static final ThreadLocal<RequestAttributes> requestAttributesHolder = new NamedThreadLocal("Request attributes");
    private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder = new NamedInheritableThreadLocal("Request context");

    public RequestContextHolder() {
    }