Import java.security.nosuchalgarithmexception;

Public class MD5 {

Private MessageDigest md

Private static MD5 md5

Private MD5 ()

{

Try {

MD = message digest . getinstance(" MD5 ")；

} catch(nosuch algorithm exception e){

System.out.println ("no such algorithm");

}

}

//Generate an MD5 instance.

Public static MD5 getInstance ()

{

if(null！ =md5)

Return to md5

other

{

make instance()；

Return to md5

}

}

//Make sure that only one thread uses MD5 encryption at the same time.

Private static synchronization void makeInstance ()

{

if(null==md5)

MD5 = new MD5()；

}

Common string createMD5 (string passing)

{

MD . update(pass . getbytes())；

byte[]b = MD . digest()；

Returns bytetohexstring (b);

}

Private string byteToHexString(byte[] b)

{

string buffer sb = new string buffer()；

String temp =

for(int I = 0； I<b. Length; i++)

{

temp = integer . tohexstring(b[I]& amp； 0x ff)；

if(temp.length()== 1)

temp = " 0 "+temp；

Sb.append (temporary);

}

return sb . tostring()；

}

Public static void main(String[] args) {

system . out . println(MD5 . getinstance()create MD5(" 123 "))； }}