pagehelper.Page分页查询报错

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我是靠谱客的博主野性星月，最近开发中收集的这篇文章主要介绍pagehelper.Page分页查询报错，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

今天在写查询的时候突然遇到了一个问题，虽然这个问题以前也是遇到过但是解决方法忘记了，经过查询终于记起来解决方法，在此记录一下：

报错信息如下（简单复制了一点）：

log4j:WARN No appenders could be found for logger (com.zit.epms.controller.CheckTemporaryTrafficPermitInfoController).
log4j:WARN Please initialize the log4j system properly.
java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.github.pagehelper.Page
   at com.zit.epms.controller.CheckTemporaryTrafficPermitInfoController.temporaryTrafficPermitInfoCheckSearch(CheckTemporaryTrafficPermitInfoController.java:137)
   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 org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
   at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
   at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
   at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
   at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
   at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
   at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
   at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
   at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
   at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
   at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)

代码如下：

@RequestMapping("/temporaryTrafficPermitInfoCheckSearch")
   public ModelAndView temporaryTrafficPermitInfoCheckSearch(HttpServletRequest request,Integer curr,Integer limit,
           TemporaryTrafficPermitInfo temporaryTrafficPermitInfo) {
       ModelAndView mView = new ModelAndView();
       mView.setView(Jackson2Util.jsonView());
       PageHelper.startPage(curr, limit);
       long total = 0;
       currentUser = (User) request.getSession().getAttribute("currentUser");
       try {
           if(null!=currentUser) {
               BrigadeInfo brigadeInfo = brigadeInfoService.searchByBrigadeName(currentUser.getName());
               if(StringUtil.isNotEmpty(String.valueOf(brigadeInfo.getId()))) {
               List<EnranceInfo> enranceInfos = enranceInfoService.selectEntrance(brigadeInfo.getId());

               List<String> sunList = new ArrayList<>();
               enranceInfos.forEach((a) ->sunList.add(String.valueOf(a.getId())));

               Object[] strArray = sunList.toArray();
   Long [] idsResult = new Long[sunList.size()];
   for (int i=0;i<strArray.length;i++) {
       idsResult[i] = Long.valueOf((String) strArray[i]);
           }
               temporaryTrafficPermitInfo.setEntranceList(idsResult);
               }
           }
           List<TemporaryTrafficPermitInfo> temporaryTrafficPermitInfos = temporaryTrafficPermitInfoService.selectTemporaryTrafficPermitInfo(temporaryTrafficPermitInfo)；
           for (TemporaryTrafficPermitInfo tmp : temporaryTrafficPermitInfos) {
               if(new Date().getTime()>tmp.getYxjs().getTime()) {
                   tmp.setDqztString(DqztEnum.OUT_DATE.getValue());
               }else {
                   tmp.setDqztString(DqztEnum.NOT_OUT_DATE.getValue());
               }
           }
           Page<TemporaryTrafficPermitInfo> page = (Page<TemporaryTrafficPermitInfo>)temporaryTrafficPermitInfos;
           total = page.getTotal();
           mView.addObject("count", total);
           mView.addObject("code", 0);
           mView.addObject("data", temporaryTrafficPermitInfos);
       } catch (Exception e) {
           logger.error("通行证信息查询失败", e);
           e.printStackTrace();
       }
       return mView;
   }

原因是代码中的pageHelper只会对它下一条查询语句分页生效（看代码标红位置），所以在对这个查询分页的时候会不能分页。

解决方法是将 PageHelper.startPage(curr, limit);与查询的语句放在一起。这样pagehelper会对这个语句进行分页

如下：

PageHelper.startPage(curr, limit);
           List<TemporaryTrafficPermitInfo> temporaryTrafficPermitInfos = temporaryTrafficPermitInfoService.selectTemporaryTrafficPermitInfo(temporaryTrafficPermitInfo);
           for (TemporaryTrafficPermitInfo tmp : temporaryTrafficPermitInfos) {
               if(new Date().getTime()>tmp.getYxjs().getTime()) {
                   tmp.setDqztString(DqztEnum.OUT_DATE.getValue());
               }else {
                   tmp.setDqztString(DqztEnum.NOT_OUT_DATE.getValue());
               }
           }
           Page<TemporaryTrafficPermitInfo> page = (Page<TemporaryTrafficPermitInfo>)temporaryTrafficPermitInfos;
           total = page.getTotal();