C3p0Plugin c3p0Plugin = createC3p0Plugin();
c3p0Plugin.start();
ActiveRecordPlugin arp = new ActiveRecordPlugin(c3p0Plugin);
arp.start();
arp.addMapping("tb_folder_roll_picture", "id", TbFolderRollPicture.class);

      
执行这条语句的时候，报下面这个异常？请问是哪里出现了问题，尝试了好久没有解决。
List<TbFolderRollPicture> search1 = TbFolderRollPicture.dao.find("SELECT * FROM tb_folder_roll_picture");
 
2017-08-25 17:59:43 ERROR [com.jflyfox.jfinal.component.interceptor.ExceptionInterceptor.intercept] - 异常：
java.lang.NullPointerException
at com.jfinal.plugin.activerecord.Model.find(Model.java:567)
at com.jfinal.plugin.activerecord.Model.find(Model.java:584)
at com.jflyfox.modules.CommonController.search(CommonController.java:194)
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:498)
at com.jfinal.aop.Invocation.invoke(Invocation.java:73)
at com.jflyfox.component.interceptor.CommonInterceptor.intercept(CommonInterceptor.java:45)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.component.interceptor.SiteInterceptor.intercept(SiteInterceptor.java:49)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.system.user.UserInterceptor.intercept(UserInterceptor.java:84)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.component.interceptor.UpdateCacheInterceptor.intercept(UpdateCacheInterceptor.java:44)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.component.interceptor.PageViewInterceptor.intercept(PageViewInterceptor.java:33)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.component.interceptor.UserKeyInterceptor.intercept(UserKeyInterceptor.java:28)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.jfinal.component.interceptor.JflyfoxInterceptor.intercept(JflyfoxInterceptor.java:26)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.jfinal.component.interceptor.SessionAttrInterceptor.intercept(SessionAttrInterceptor.java:48)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jfinal.ext.interceptor.SessionInViewInterceptor.intercept(SessionInViewInterceptor.java:44)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jflyfox.jfinal.component.interceptor.ExceptionInterceptor.intercept(ExceptionInterceptor.java:38)
at com.jfinal.aop.Invocation.invoke(Invocation.java:67)
at com.jfinal.core.ActionHandler.handle(ActionHandler.java:74)
at com.jflyfox.jfinal.component.handler.CurrentPathHandler.handle(CurrentPathHandler.java:53)
at com.jfinal.ext.handler.ContextPathHandler.handle(ContextPathHandler.java:47)
at com.jflyfox.jfinal.component.handler.BasePathHandler.handle(BasePathHandler.java:48)
at com.jflyfox.jfinal.component.handler.HtmlHandler.handle(HtmlHandler.java:48)
at com.jfinal.core.JFinalFilter.doFilter(JFinalFilter.java:72)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1487)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:499)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:427)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
at org.eclipse.jetty.server.Server.handle(Server.java:370)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:973)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1035)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:641)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:231)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:696)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:53)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:745)