php连接mysql时报错 SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client

php连接mysql时报错 SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client

原因是 mysql8默认的身份验证方式是：caching_sha2_password

用phpinfo查询 loaded plugins，如果少了caching_sha2_password，就表明此版本的php不支持此验证方式

解决方法为：

1、打开mysql命令行工具

2、执行命令 

      ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '111111';