架构师训练营 第十一周【作业】

package week11;
import java.security.MessageDigest;
public class PwdCheckUtil {
	public final static String _salt="xxxxxx";
	/**
	 * 验证用户密码是否正确
	 * @param userId 用户id
	 * @param pwd 明文密码
	 * @param encPwd 密文密码
	 * @return boolean 密码是否正确
	 */
	public static boolean checkPW(String userId,String pwd,String encPwd) {
		if(将3个字段进行非null且非""判断) {
			return false;
		}
		return MD5Encrypt(userId+_salt+pwd).equals(encPwd);
	}
	
	/**MD5加密为16进制**/
    public static String MD5Encrypt(String encryptStr){
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] bytes = md.digest(encryptStr.getBytes("utf-8"));
            return parseByte2HexStr(bytes);//将二进制转换成16进制
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    
    /**将二进制转换成16进制
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }
}