Combing the MD5 encryption code recently, two pieces of code is a simple, a tedious, specific as follows:

The first paragraph:

 
Public static String getMD5String (String STR) {
Try {
//return an implementation of the MD5 algorithm message digest object 
The MessageDigest MessageDigest=MessageDigest. GetInstance (" MD5 "); 
MessageDigest. Update (STR) getBytes ()); 
Byte [] bytes=messageDigest. Digest (); 

Bytes, return the new BigInteger (1) the toString (16); 
} the catch (NoSuchAlgorithmException e) {
e.printStackTrace(); 
} 
return null; 
} 

The second section:

 
Public final static String MD5Test (String res) {
Char hexDigits []={' 0 ', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
'a', 'b', 'c', 'd', 'e', 'f'}; 
Try {
Byte [] strTemp=res. GetBytes (); 
The MessageDigest MessageDigest=MessageDigest. GetInstance (" MD5 "); 
The messageDigest. Update (strTemp); 
Byte [] md=messageDigest. Digest (); 
Int j=md length; 
Char STR []=new char [j * 2]; 
Int k=0; 
for (int i=0; I & lt; j; I++) {
Byte byte0=md [I]; 
STR=hexDigits [k++] [byte0 & gt; & gt; & gt; 4 & amp; 0 xf]; 
STR=hexDigits [k++] [byte0 & amp; 0 xf]; 
} 
String dd=new String (STR); 
Return the dd. 
} the catch (Exception e) {
return null; 
} 
} 

These two code incoming parameters "hello", the result of the input is "5 d41402abc4b2a76b9719d911017c592
"
Why can meet the demand, the first piece of code to write the code as complex as the second paragraph? Please master much guidance.

CodePudding user response:

I suddenly understood