spring boot整合mybatis时报空指针异常

java.lang.NullPointerException: null
	at com.alibaba.druid.wall.WallProvider.checkInternal(WallProvider.java:701) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.wall.WallProvider.check(WallProvider.java:578) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.wall.WallFilter.checkInternal(WallFilter.java:793) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.wall.WallFilter.check(WallFilter.java:788) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.wall.WallFilter.statement_execute(WallFilter.java:421) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterChainImpl.statement_execute(FilterChainImpl.java:2956) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterAdapter.statement_execute(FilterAdapter.java:2474) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterEventAdapter.statement_execute(FilterEventAdapter.java:188) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterChainImpl.statement_execute(FilterChainImpl.java:2956) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterAdapter.statement_execute(FilterAdapter.java:2474) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterEventAdapter.statement_execute(FilterEventAdapter.java:188) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.filter.FilterChainImpl.statement_execute(FilterChainImpl.java:2956) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.proxy.jdbc.StatementProxyImpl.execute(StatementProxyImpl.java:147) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.pool.vendor.MSSQLValidConnectionChecker.isValidConnection(MSSQLValidConnectionChecker.java:50) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.pool.DruidAbstractDataSource.validateConnection(DruidAbstractDataSource.java:1384) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.pool.DruidDataSource.shrink(DruidDataSource.java:3056) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.pool.DruidDataSource$DestroyTask.run(DruidDataSource.java:2793) ~[druid-1.1.17.jar:1.1.17]
	at com.alibaba.druid.pool.DruidDataSource$DestroyConnectionThread.run(DruidDataSource.java:2777) ~[druid-1.1.17.jar:1.1.17]

项目可以启动，而且隔几秒这个相同的异常又多一个