import java.security.MessageDigest;    import java.security.NoSuchAlgorithmException;        public class Md5Code {            public String Md5(String plainText)        {            System.out.println("加密前:"+plainText);            try {                MessageDigest md = MessageDigest.getInstance("MD5");                md.update(plainText.getBytes());                byte[] b = md.digest();                                int i;                StringBuffer buf = new StringBuffer("");                for (int offset = 0; offset < b.length; offset++)                 {                    i = b[offset];                    if (i<0) i+=256;                    if(i<16)                    buf.append("0");                    buf.append(Integer.toHexString(i));                                        }                                System.out.println("加密后："+buf.toString());                return buf.toString();            } catch (NoSuchAlgorithmException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            return plainText;        }                    }