• When using jdbc to connect to the postgresql database, the following error occurs:

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 (????????: ?????? "uav_test " ??????) ### The error may exist in file [G:\Uav\NewMavenDemo\target\classes\mapper\UserMapper.xml] ### The error may involve UserMapper.getUserInfo ### The error occurred while executing a query ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (????????: ?????? "uav_test " ??????) at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:79) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:447) at com.sun.proxy.$Proxy27.selectList(Unknown Source)

• Key error message:Cannot create PoolableConnectionFactory (????????: ?????? "uav_test " ??????)

• The connection parameters are as follows:

#Postgresql driver=org.postgresql.Driver url=jdbc:postgresql://localhost:5432/uav_test username=postgres password=root dialect=postgresql

• There is no problem when I change the postgresql database to use mysql. The parameters for mysql:

driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/mysql username=root password=root dialect=mysql

• I don’t quite understand why this happens