getServletContext().getResource()引發的錯誤原因

getServletContext().getResource()引發的錯誤

tomcat4.1:

    /**
     * Return a URL object of a resource that is mapped to the
     * specified context-relative path.
     *
     * @param path Context-relative path of the desired resource
     *
     * @exception MalformedURLException if the resource path is
     *  not properly formed
     */
    public URL getResource(String path) throws MalformedURLException {

        if (!path.startsWith("/"))
            throw new MalformedURLException("Path '" + path +
                                            "' does not start with '/'");
        return (new URL(myResourceBaseURL, path.substring(1)));

    }

tomcat 5.5:

    public URL getResource(String path)
        throws MalformedURLException {
     System.out.println("qik:"+path);
        if (path == null || !path.startsWith("/")) {
            throw new MalformedURLException(sm.getString("applicationContext.requestDispatcher.iae", path));
        }
       
        path = normalize(path);
        if (path == null)
            return (null);

        String libPath = "/WEB-INF/lib/";
        if ((path.startsWith(libPath)) && (path.endsWith(".jar"))) {
            File jarFile = null;
            if (context.isFilesystemBased()) {
                jarFile = new File(basePath, path);
            } else {
                jarFile = new File(context.getWorkPath(), path);
            }
            if (jarFile.exists()) {
                return jarFile.toURL();
            } else {
                return null;
            }
        } else {

            DirContext resources = context.getResources();
            if (resources != null) {
                String fullPath = context.getName() + path;
                String hostName = context.getParent().getName();
                try {
                    resources.lookup(path);
                    return new URL
                        ("jndi", "", 0, getJNDIUri(hostName, fullPath),
                         new DirContextURLStreamHandler(resources));
                } catch (Exception e) {
                    // Ignore
                }
            }
        }

        return (null);

    }

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程式的架構通過使用getResource時，不小心傳入了一個""，造成了在tomcat5上面運行出錯，提示Path does not start with "/"