Java: MD5 encrypted string

Back up a small program. Use MD5 to encrypt the file and generate a ciphertext source program. Very easy to use.

Import java. Security. messagedigest;
Import java. Security. nosuchalgorithmexception;
Import java. Io .*;

Public class encryptutil
{
/**
*
* @ Param filepath the full path of the file
* @ Return
* @ Throws exception
*/
Public static string encrypt (string filepath) throws exception
{
String instr = getstring (filepath );
Messagedigest MD = NULL;
String out = NULL;

Try
{
MD = messagedigest. getinstance ("MD5 ");
Byte [] digest = md. Digest (instr. getbytes ());
Out = byte2hex (Digest );
}
Catch (nosuchalgorithmexception E)
{
E. printstacktrace ();
Throw E;
}

Return out;
}

Private Static string byte2hex (byte [] B)
{
String HS = "";
String stmp = "";
For (INT n = 0; n <B. length; n ++)
{
Stmp = (Java. Lang. Integer. tohexstring (B [N] & 0xff ));
If (stmp. Length () = 1)
{
HS = HS + "0" + stmp;
}
Else
{
HS = HS + stmp;
}
}
Return HS. touppercase ();
}

Private Static string getstring (string filepath) throws exception
{
Stringbuffer sbuf = new stringbuffer ();
Try
{
Filereader Fr = new filereader (filepath );
Bufferedreader BR = new bufferedreader (FR );

String line = Br. Readline ();

While (line! = NULL)
{
Sbuf. append (line );
Sbuf. append ("/R/N ");
Line = Br. Readline ();
}
BR. Close ();
Fr. Close ();
}
Catch (exception E)
{
E. printstacktrace ();
Throw E;
}
// System. Out. println (sbuf. tostring ());

Return sbuf. tostring (). Trim ();
}

Public static void main (string [] ARGs) throws exception
{
If (ARGs. length> 0)
{
String result = NULL;
Try
{
Result = encrypt (ARGs [0]);
}
Catch (exception E)
{
E. printstacktrace ();
}
System. Out. println (ARGs [0] + ":" + result );
// System. Out. println (ARGs [1] + ":" + encrypt (ARGs [1]);
}
Else
{
System. Out. println ("the file does not exist ");
}
}
 
}