org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:   ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Access denied for user 'woshin'@'localhost' (using password: YES))   ### The error may exist in ssm/mapper/ItemsMapper.xml   ### The error may involve ssm.mapper.ItemsMapper.selectByPrimaryKey   ### The error occurred while executing a query   ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested     需要查看pom.xml db.properties 尝试做如下修改： 1版本问题，尝试修改版本 8.0.15       mysql     mysql-connector-java     8.0.15   2.更改db.properties jdbc.driver=com.mysql.cj.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/mydb?rewriteBatchedStatements=true&useUnicode=true&characterEncoding=utf8&serverTimezone=UTC&useSSL=false jdbc.username=root jdbc.password=123456 ​ 备注：记得路径问题