周练习 11

package com.example.week11;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class TestEncode {
    public static void main(String[] args) {
        String userID = "4J29XLNfVUYBdmaZr8nwz7hqHTI5gpce";
        String password = "4Mxn65RrhD3ILdAF";
        String encodePassword = "2a06df1dcc707f610dcdd479b151ec40";
        Boolean checkResult = checkPW(userID, password, encodePassword);
        System.out.println(String.format("userID : %s, password : %s, encodePassword : %s, checkResult : %s", userID, password, encodePassword, checkResult));
    }
    public static Boolean checkPW(String userID, String password, String encodePassword) {
        String md5 = stringToMD5(userID + password);
        return  encodePassword.equals(md5);
    }
    public static String stringToMD5(String plainText) {
        byte[] secretBytes = null;
        try {
            secretBytes = MessageDigest.getInstance("md5").digest(
                    plainText.getBytes());
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("没有这个md5算法！");
        }
        String md5code = new BigInteger(1, secretBytes).toString(16);
        for (int i = 0; i < 32 - md5code.length(); i++) {
            md5code = "0" + md5code;
        }
        return md5code;
    }
}

userID : 4J29XLNfVUYBdmaZr8nwz7hqHTI5gpce, password : 4Mxn65RrhD3ILdAF, 
encodePassword : 2a06df1dcc707f610dcdd479b151ec40, checkResult : true