[ERROR]-[Thread: http-bio-9999-exec-8]-[com.jfinal.core.ActionHandler.handle()]: /blog/

java.lang.NullPointerException

at com.jfinal.plugin.activerecord.Model.doPaginate(Model.java:329)

at com.jfinal.plugin.activerecord.Model.paginate(Model.java:303)

at com.demo.blog.BlogService.paginate(BlogService.java:22)

at com.demo.blog.BlogController.index(BlogController.java:20)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:606)

at com.jfinal.aop.Invocation.invoke(Invocation.java:73)

at com.demo.blog.BlogInterceptor.intercept(BlogInterceptor.java:17)

at com.jfinal.aop.Invocation.invoke(Invocation.java:67)

at com.jfinal.core.ActionHandler.handle(ActionHandler.java:74)

at com.jfinal.core.JFinalFilter.doFilter(JFinalFilter.java:74)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)

at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)

at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)

at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:745)

@JFinal  请问这个是因为什么引起的？是数据库连接问题么？我在阿里云上部署的项目。数据库连接应该怎么写呢。数据库是阿里云本地装进去的。