spring HttpServletRequest 簡介

前提：工做遇到controller中經過註解的方式注入

@Resource
private HttpServletRequest request;

咱們都知道spring 默認是單例，當遇到併發的時候線程不安全，可是通過測試它安全的。

綜上，肯定spring確定對它作了處理，所以打開個人探索之路.....

上源碼

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());
　　　　　　　　//放到這裏了，RequestContextHolder下的requestAttributes讓咱們跟進去瞅瞅
            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());　　//原來如此啊，是經過threadLocal去保證的    private static final ThreadLocal<RequestAttributes> requestAttributesHolder = new NamedThreadLocal("Request attributes");    private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder = new NamedInheritableThreadLocal("Request context");    public RequestContextHolder() {    }