MySQL 错误：访问被拒绝 - 解决方案 - 常规

2023-10-16 15:58:12,078 [I] SQL statement execution failed!! retrying attempt 2 of total 3 Loading class com.mysql.jdbc.Driver'. This is deprecated. The new driver class is com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary. SQLException : SQL state: 42000 java.sql.SQLSyntaxErrorException: Access denied for user 'root'@'%' to database 'db_ranger' ErrorCode: 1044 SQLException : SQL state: 42000 java.sql.SQLSyntaxErrorException: Access denied for user 'root'@'%' to database 'db_ranger' ErrorCode: 1044 2023-10-16 15:58:13,477 [I] SQL statement execution failed!! retrying attempt 3 of total 3 Loading class com.mysql.jdbc.Driver'. This is deprecated. The new driver class is com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary. SQLException : SQL state: 42000 java.sql.SQLSyntaxErrorException: Access denied for user 'root'@'%' to database 'db_ranger' ErrorCode: 1044 SQLException : SQL state: 42000 java.sql.SQLSyntaxErrorException: Access denied for user 'root'@'%' to database 'db_ranger' ErrorCode: 1044 2023-10-16 15:58:13,878 [E] Granting privileges to 'ranger' failed on 'db_ranger'

上述错误提示是由于用户'root'在数据库'db_ranger'上没有访问权限导致的。要解决此问题，您可以按照以下步骤进行操作：

使用管理员权限登录MySQL数据库。
确保用户'root'具有访问数据库的权限。您可以运行以下命令来授予'root'用户访问'db_ranger'数据库的权限：
```
GRANT ALL PRIVILEGES ON db_ranger.* TO 'root'@'%' WITH GRANT OPTION;
```
这将授予用户'root'在所有IP地址上对'db_ranger'数据库的完全访问权限。
如果您不希望使用'root'用户，您可以创建一个新的用户并为其授予访问数据库的权限。例如，您可以创建一个名为'ranger'的新用户，并授予其访问'db_ranger'数据库的权限：
```
CREATE USER 'ranger'@'%' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON db_ranger.* TO 'ranger'@'%' WITH GRANT OPTION;
```
在上述命令中，将'password'替换为新用户的密码。
完成以上更改后，重新运行您的应用程序或尝试执行SQL语句，应该不再出现访问被拒绝的错误。

请注意，为了安全起见，建议限制用户的访问权限，并仅授予其所需的最低权限。