java 7中可以判断文件的contenttype了
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.