存在Servlet A，其url-pattern为 /A/*，则形如/A,/A/bcd,/A/b/c/d等式样的请求全部能够被Servlet A匹配上。

但是SpringMVC的DispatcherServlet的url-pattern /A/*只能匹配上/A式样的请求，/A/abc，/A/b/c等式样的均匹配不上。

debug发现，org.springframework.web.util.UrlPathHelper.getPathWithinServletMapping()方法会将请求路径中与url-pattern配置一致的路径（servletPath）截去，然后用剩下的部分去匹配，不知这么做的用意是什么，还请各位不吝赐教

/**     * Return the path within the servlet mapping for the given request,     * i.e. the part of the request's URL beyond the part that called the servlet,     * or "" if the whole URL has been used to identify the servlet.     * 
Detects include request URL if called within a RequestDispatcher include.     * 
E.g.: servlet mapping = "/*"; request URI = "/test/a" -> "/test/a".     * 
E.g.: servlet mapping = "/"; request URI = "/test/a" -> "/test/a".     * 
E.g.: servlet mapping = "/test/*"; request URI = "/test/a" -> "/a".     * 
E.g.: servlet mapping = "/test"; request URI = "/test" -> "".     * 
E.g.: servlet mapping = "/*.test"; request URI = "/a.test" -> "".     * @param request current HTTP request     * @return the path within the servlet mapping, or ""     */    public String getPathWithinServletMapping(HttpServletRequest request) {        String pathWithinApp = getPathWithinApplication(request);        String servletPath = getServletPath(request);        String sanitizedPathWithinApp = getSanitizedPath(pathWithinApp);        String path;        // 不能理解此处的用意何在        // If the app container sanitized the servletPath, check against the sanitized version        if (servletPath.contains(sanitizedPathWithinApp)) {            path = getRemainingPath(sanitizedPathWithinApp, servletPath, false);        }        else {            path = getRemainingPath(pathWithinApp, servletPath, false);        }        if (path != null) {            // Normal case: URI contains servlet path.            return path;        }        else {            // Special case: URI is different from servlet path.            String pathInfo = request.getPathInfo();            if (pathInfo != null) {                // Use path info if available. Indicates index page within a servlet mapping?                // e.g. with index page: URI="/", servletPath="/index.html"                return pathInfo;            }            if (!this.urlDecode) {                // No path info... (not mapped by prefix, nor by extension, nor "/*")                // For the default servlet mapping (i.e. "/"), urlDecode=false can                // cause issues since getServletPath() returns a decoded path.                // If decoding pathWithinApp yields a match just use pathWithinApp.                path = getRemainingPath(decodeInternal(request, pathWithinApp), servletPath, false);                if (path != null) {                    return pathWithinApp;                }            }            // Otherwise, use the full servlet path.            return servletPath;        }    }