Java计算文件的SHA码和MD5码

可参考:http://blog.csdn.net/hudashi/article/details/8394158

     /**
      * 计算文件的MD5码
      * @param file
      * @return
      */
     public static String getMD5(File file) {
         FileInputStream fis = null;
         try {
             MessageDigest md = MessageDigest.getInstance("MD5");
             fis = new FileInputStream(file);
             byte[] buffer = new byte[8192];
             int length = -1;
             System.out.println("开始算");
             while ((length = fis.read(buffer)) != -1) {
                 md.update(buffer, 0, length);
             }
             System.out.println("算完了");
             return bytesToString(md.digest());
         } catch (IOException ex) {
             Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             return null;
         } catch (NoSuchAlgorithmException ex) {
             Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             return null;
         } finally {
             try {
                 fis.close();
             } catch (IOException ex) {
                 Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             }
         }
     }

     /**
      * 得到文件的SHA码,用于校验
      * @param file
      * @return
      */
     public static String getSHA(File file) {
         FileInputStream fis = null;
         try {
             MessageDigest md = MessageDigest.getInstance("SHA");
             fis = new FileInputStream(file);
             byte[] buffer = new byte[8192];
             int length = -1;
             System.out.println("开始算");
             while ((length = fis.read(buffer)) != -1) {
                 md.update(buffer, 0, length);
             }
             System.out.println("算完了");
             return bytesToString(md.digest());
         } catch (IOException ex) {
             Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             return null;
         } catch (NoSuchAlgorithmException ex) {
             Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             return null;
         } finally {
             try {
                 fis.close();
             } catch (IOException ex) {
                 Logger.getLogger(MD5Util.class.getName()).log(Level.SEVERE, null, ex);
             }
         }
     }