java 7中可以判断文件的contenttype了,例子如下:

Path path = Paths.get("D:/Downloads/java.txt");

        String contentType = null;

        try {

            contentType = Files.probeContentType(path);

        } catch (IOException e) {



            e.printStackTrace();

        }

        System.out.println("File content type is : " + contentType);



    }

就是使用Files.probeContentType方法了.