package **;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class MD5 {

    /**

     * MD5加密算法，参数选择16还是32位

     * 默认为32位

     * @param plainText 需加密的文本

     * @param md5Type   16/32

     * @return 加密后的密文

     */

    public static String Md5(String plainText,String md5Type) {

        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));

            }

            if(md5Type!=null&&!md5Type.trim().equals("")&&md5Type.trim().equals("16")){

                return buf.toString().substring(8, 24).toUpperCase();// 16位的加密

            }else{

                return buf.toString().toUpperCase();// 32位的加密大写

            }

        } catch (NoSuchAlgorithmException e) {

            e.printStackTrace();

            return null;

        }

    }

    public static void main(String[] args) {

        Md5("123456","16");

        System.out.println(Md5("123456","16"));

        Md5("123456","32");

        System.out.println(Md5("123456","32"));

        System.out.println(Md5("123456","32").equals("E10ADC3949BA59ABBE56E057F20F883E"));

        System.out.println(Md5("123456","16").equals("49BA59ABBE56E057"));

    }

}