Navicat连接不上，总是报错1251；
    原因是MySQL8.0版本的加密方式和MySQL5.0的不一样，连接会报错。
    试了很多种方法，终于找到一种可以实现的：
    更改加密方式
    **
    1.先通过命令行进入mysql的root账户：
    PS C:\Windows\system32> mysql -uroot -p

    再输入root的密码：
    Enter password: **
    Welcome to the MySQL monitor. Commands end with ; or \g.
    Your MySQL connection id is 18
    Server version: 8.0.11 MySQL Community Server - GPL
    Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.
    Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.
    mysql>
    2.更改加密方式：
    mysql> ALTER USER ‘root’@’localhost’ IDENTIFIED BY ‘password’ PASSWORD EXPIRE NEVER;
    Query OK, 0 rows affected (0.10 sec)

    3.更改密码：
    mysql> ALTER USER ‘root’@’localhost’ IDENTIFIED WITH mysql_native_password BY ‘password’;
    Query OK, 0 rows affected (0.35 sec)

    4.刷新：
    mysql> FLUSH PRIVILEGES;
    Query OK, 0 rows affected (0.28 sec)