JAVA加密算法系列-MD5

Posted 2020-08-31 The first wings

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"));
        
    }
}