code: public static boolean checkMd5sum(File file, String checkCode) throws IOException {
  		DigestInputStream dInput = null;
  		try {
  			FileInputStream fInput = new FileInputStream(file);
  			dInput = new DigestInputStream(fInput, getMd5Instance());
  			byte[] buf = new byte[8192];
  			while (dInput.read(buf) > 0) {
  			}
  			byte[] bytes = dInput.getMessageDigest().digest();
  			return bytes2hex(bytes).equals(checkCode);
  		} finally {
  			closeQuietly(dInput);
  		}
  	}
docs: 检查指定文件的md5sum和指定的检验码是否一致。
  
  @param file 需要检验的文件
  @param checkCode 已知的md5sum检验码
  @return true/false