解决Springboot + MyBatis框架“Cause: org.springframework.jdbc.CannotGetJdbcConnectionException”问题

目录

1 出错类型一（连接MySQL失败）

2 出错类型二（MySQL密码错误）

3 出错类型三（XXXMapper.xml中SQL语句语法问题） 

1 出错类型一（连接MySQL失败）

### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Access denied for user 'root'@'127.0.0.1' to database 'db_onlineexam'

解决：重新安装mysql

2 出错类型二（MySQL密码错误）

### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

 Bug:

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
### The error may exist in file [D:IdeaProjectsonlineExamtargetclassesmapperUserMapper.xml]
### The error may involve com.nenusoftware.onlineexam.mapper.UserMapper.selectByName
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

解决：仔细查看Bug里面的Cause一行，检查用户名和密码是否正确

3 出错类型三（XXXMapper.xml中SQL语句语法问题） 

解决：检查sql语句是否正确