获得一个流对象，用类加载器方式和用new方式有什么不同？

第一种：

    public static InputStream openStream(String resource) {
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        InputStream stream = classLoader.getResourceAsStream(resource);
        if (stream == null) {
            stream = StreamHelper.class.getClassLoader().getResourceAsStream(resource);
        }
        return stream;
    }

第二种：

    public static InputStream getStreamFromFile(File file) throws Exception {
        InputStream stream = null;
        try {
            if (!file.exists()) {
                throw new Exception("file " + file + " doesn't exist");
            }
            if (file.isDirectory()) {
                throw new Exception("file " + file + " is a directory");
            }
            stream = new FileInputStream(file);

        } catch (Exception e) {
            throw new Exception("couldn't access file " + file + ": " + e.getMessage());
        }
        return stream;
    }

第一种创建的流用来读取资源内容；第二种创建的流用来读取文件内容。