List<Record> users = Db.find("select username from pw_user where user_id > 1");

之前用的好好的 ，现在用了报了以下的错

java.lang.NullPointerException

at com.jfinal.plugin.activerecord.Db.find(Db.java:240)

at com.gx.web.MainController.daorushp(MainController.java:290)

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.jfinal.core.ActionHandler.handle(ActionHandler.java:82)

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:218)

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:169)

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

at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)

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

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1083)

at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:640)

at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)

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)