DispatcherServlet 匹配请求路径时的疑惑

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

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/**      * 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.      * <p>Detects include request URL if called within a RequestDispatcher include.      * <p>E.g.: servlet mapping = "/*"; request URI = "/test/a" -> "/test/a".      * <p>E.g.: servlet mapping = "/"; request URI = "/test/a" -> "/test/a".      * <p>E.g.: servlet mapping = "/test/*"; request URI = "/test/a" -> "/a".      * <p>E.g.: servlet mapping = "/test"; request URI = "/test" -> "".      * <p>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;         }     }