import java.security.*;
import java.security.spec.*;
class MD5_Test...{
????
????public final static String MD5(String s)...{
????????char hexDigits[] = ...{''0'', ''1'', ''2'', ''3'', ''4'', ''5'', ''6'', ''7'', ''8'', ''9'', ''a'', ''b'', ''c'', ''d'',''e'', ''f''};
????????try
????????...{
????????????byte[] strTemp = s.getBytes();
????????????MessageDigest mdTemp = MessageDigest.getInstance("MD5");
????????????mdTemp.update(strTemp);
????????????byte[] md = mdTemp.digest();
????????????int j = md.length;
????????????char str[] = new char[j * 2];
????????????int k = 0;
????????????for (int i = 0; i < j; i++)
????????????...{
????????????????byte byte0 = md ;
????????????????str[k++] = hexDigits[byte0 >>>4 & 0xf];
????????????????str[k++] = hexDigits[byte0 & 0xf];
????????????}
????????????return new String(str);
????????}
????????catch (Exception e)
????????...{
????????????return null;
????????}
????}
}

主程序如下：


public class md5_main ...{
????public static void main (String[] args)
????...{
????????//MD5_Test aa = new MD5_Test("password");
????????String string= MD5_Test.MD5("password");
????????System.out.println(MD5_Test.MD5("password"));
????????System.out.println(string.equals("5f4dcc3b5aa765d61d8327deb882cf99"));
????}
}