Spring boot使用pagehelper 报空指针异常

项目中使用Mybatis+pagehelper正常运行没有问题，应需求要求需要配置多数据源，可是当我配置完后，新的数据源正常运行，原来查询的都出空指针异常了、
错误如下：

2017-09-20 19:59:40.256 ERROR 17836 --- [nio-1010-exec-1] .p.s.c.m.e.GlobalDefaultExceptionHandler : -----------------------全局统一异常异常处理-----------------------2017-09-20 19:59:40.260 ERROR 17836 --- [nio-1010-exec-1] .p.s.c.m.e.GlobalDefaultExceptionHandler : org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database.  Cause: java.lang.NullPointerException### The error may exist in com/paic/srvbot/change/dao/StepDao.java (best guess)### The error may involve com.paic.srvbot.change.dao.StepDao.selectByExample_COUNT### The error occurred while handling results### SQL: SELECT count(0) FROM srv_change_step LIMIT 10### Cause: java.lang.NullPointerException    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77)    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)    at com.sun.proxy.$Proxy123.selectList(Unknown Source)    at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137)    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75)    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)    at com.sun.proxy.$Proxy161.selectByExample(Unknown Source)    at com.paic.srvbot.change.service.impl.StepServiceImpl.findSteps(StepServiceImpl.java:64)    at com.paic.srvbot.change.service.impl.StepServiceImpl$$FastClassBySpringCGLIB$$a9da154a.invoke(<generated>)    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:721)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:656)    at com.paic.srvbot.change.service.impl.StepServiceImpl$$EnhancerBySpringCGLIB$$f955a0c0.findSteps(<generated>)    at com.paic.srvbot.change.controller.StepController.find(StepController.java:46)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:497)    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:208)    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:105)    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474)    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)    at java.lang.Thread.run(Thread.java:745)Caused by: org.apache.ibatis.exceptions.PersistenceException: ### Error querying database.  Cause: java.lang.NullPointerException### The error may exist in com/paic/srvbot/change/dao/StepDao.java (best guess)### The error may involve com.paic.srvbot.change.dao.StepDao.selectByExample_COUNT### The error occurred while handling results### SQL: SELECT count(0) FROM srv_change_step LIMIT 10### Cause: java.lang.NullPointerException    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)    at java.lang.reflect.Method.invoke(Method.java:497)    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)    ... 78 moreCaused by: java.lang.NullPointerException    at com.github.pagehelper.dialect.AbstractHelperDialect.afterCount(AbstractHelperDialect.java:71)    at com.github.pagehelper.PageHelper.afterCount(PageHelper.java:73)    at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:115)    at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)    at com.sun.proxy.$Proxy210.query(Unknown Source)    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)    ... 84 more

原因是依赖引得不对
原来的

application.properties

pagehelper.helperDialect=PostgreSQL

重点内容

        <dependency>            <groupId>com.github.pagehelper</groupId>            <artifactId>pagehelper-spring-boot-starter</artifactId>            <version>1.1.0</version>        </dependency>

更改后的

       <dependency>            <groupId>com.github.pagehelper</groupId>            <artifactId>pagehelper</artifactId>            <version>5.0.0</version>       </dependency>

猜测是因为原来的pagehelper配置是写在配置文件中，springboot会自动读取配置，现在写在重写的sqlSessionFactory类中。
重写sqlSessionFactory的原因是两个数据源一个是PG一个是ORACLE，他们使用的pagehelper.helperDialect不同，所以要单独配置