获取文件的MD5值

public  void getMd5OfFile() {
　　　　　　//这是从mongodb获取的文件流
         //DBObject dbObject = new BasicDBObject("filename","yansebuyiyangdeyanhuo5");
         //DB db = mongoTemplate.getDb();
         //GridFS fs = new GridFS(db,"myfiles");
         //GridFSDBFile gridFSDBFile = fs.findOne(dbObject);
         //InputStream in = gridFSDBFile.getInputStream();
　　　　　String filePath = "文件路径";
　　　　　InputStream is = null;
　　　　　try{
        　　in = new FileInputStram(new File(filePath));
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            byte[] bytes = new byte[1024];
            int byteCount = 0;
            while ((byteCount = in.read(bytes)) !=-1) {
                messageDigest.update(bytes, 0, byteCount);
            }
            byte[] digest = messageDigest.digest();

            // byte -128 ---- 127
            StringBuffer sb = new StringBuffer();
            for (byte b : digest) {
                int a = b & 0xff;
                // Log.d(TAG, "" + a);
                String hex = Integer.toHexString(a);

                if (hex.length() == 1) {
                    hex = 0 + hex;
                }
                sb.append(hex);
            }
        System.err.println("MD5值为：================================"+sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                in = null;
            }
        }
    }

//获取字符串的md5值
 public void  getMd5ofString( ){
        String text = "AABJRU5ErkJggg==";
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("md5");
            byte[] buffer = messageDigest.digest(text.getBytes());
            // byte -128 ---- 127
            StringBuffer sb = new StringBuffer();
            for (byte b : buffer) {
                int a = b & 0xff;
                String hex = Integer.toHexString(a);
                if (hex.length() == 1) {
                    hex = 0 + hex;
                }
                sb.append(hex);
            }
            System.err.println("MD5值为：================================"+sb.toString());
        } catch (NoSuchAlgorithmException e) {
        }
    }