一个JAVA MD5加密

主要容易出错的地方是byte[] passByte 向字符串的转化，不能直接用passByte.toString();

 

 

public void testaaa() {
     try {  
       MessageDigest messageDigest = MessageDigest.getInstance("MD5");
      
             messageDigest.reset();
             String ss="hello";
             messageDigest.update(ss.trim().getBytes()); //pass为用户注册时输入的代码

            
            
            
             byte[] passByte = messageDigest.digest();

             int i;
             StringBuffer buf = new StringBuffer("");
             for (int offset = 0; offset < passByte.length; offset++) {
             i = passByte[offset];
             if(i<0) i+= 256;
             if(i<16)
             buf.append("0");
             buf.append(Integer.toHexString(i));

             }
             ss = buf.toString(); //将加密后的密文转成字符串赋给pass，最后传到数据库的是pass

             System.out.println(ss);
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
      }  

      

    }