在春季可分页以在List< Object>上分页不管用 [英] Pageable in spring for paging on List<Object> is not working

问题描述

我有一个包含10000条记录的对象列表，我试图将该记录分成10条记录，

I have a list of object which contain 10000 records i am trying to split that records in each of 10,

但是不知何故，..有人可以看看

But somehow it is not working.. can someone have a look

@Query("select a.applicantid,coalesce(to_char(a.createdon,'yyyy-MM-dd'),to_char(filing_date,'yyyy-MM-dd')) as dt1, \r\n" + 
        "coalesce(c.companyname,i.InstituteName,(u.firstname||' '||u.lastname),\r\n" + 
        "u.firstname) ,a.c_denomination,cc.crop_common_name,cs.crop_botanical_name,\r\n" + 
        "a.id,aps.status,a.cropid, \r\n" + 
        "(select mv.varietytype from VarietyType mv where mv.id= a.varirtytypeid),\r\n" + 
        "(select sv.subvarietytype from SubVarietyType sv,VarietyType mvr \r\n" + 
        " where a.subvarietytypeid = sv.id and mvr.id= sv.varietyid),a.formtype,mcg.crop_group \r\n" + 
        " from Applications a left join ApplicantRegistration ap on \r\n" + 
        " a.applicantid = ap.id left join CompanyRegistration c on ap.companyid = c.id \r\n" + 
        " left join InstitutionRegistration i on ap.institutionid = i.id \r\n" + 
        " left join Crops cc on a.cropid = cc.id left join CropSpecies cs \r\n" + 
        " on a.cropspeciesid =cs.id left join InternalUser u on ap.id = u.applicantid \r\n" + 
        " left join ApplicationStatus aps on a.application_current_status = aps.id "
        + "left join CropGroup mcg on cc.cropgroupid = mcg.id order by a.id desc")
       List<Object[]> getapplication_adminview();



List<Object[]> admin_viewapplication=applicationrepository.getapplication_adminview();
int pageNumber = 0;
int size = 10;
Pageable pageable = PageRequest.of(pageNumber, size); // object of pageable
Page<Object> pages = new PageImpl(admin_viewapplication, pageable, admin_viewapplication.size());
List<Object> lpage = pages.getContent(); // here i am getting the lpage size as 10000 but as i enter pageable as of size 10  i am expecting 10 results only

我在哪里出错了? 如果我尝试添加可分页对象以查询并运行代码，我将收到以下错误:

where i am going wrong in this ? if i am trying to add pagable object to query and run the code i will get the following error:

无法使用请求的结果类型[java.lang.Long]为具有多个返回的查询创建TypedQuery；嵌套异常是java.lang.IllegalArgumentException:无法使用请求的结果类型[java.lang.Long]

推荐答案

我们可以使用 PagedListHolder 来更改页面列表，然后我们可以通过设置页面大小和页面来获取页面.

We can use PagedListHolder which can change the list in pages and we can than fetch a page by setting it's page size and page.

PagedListHolder<Object> page = new PagedListHolder(admin_viewapplicationpage);
      page.setPageSize(50); // number of items per page
      page.setPage(0);      // set to first page

      int totalPages = page.getPageCount(); //  gives the totalpages according to the main list
      
      List<Object> admin_viewapplication = page.getPageList();  // a List which represents the current page which is the sublist
      

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