如何鏈接jsp結果中的兩個對象？

Question

我有一個控制器，可以從數據庫獲取所有新聞，並且同時計算每條新聞上的評論數量，但是我遇到了問題，因爲即使數據正確地從數據庫中提取出來， jsp的不每條新聞的對象與它對應的評論數混合...

這裏是我的控制器：

@RequestMapping(value = "/viewstatus", method = RequestMethod.GET) 
public ModelAndView viewStatus(ModelAndView modelAndView, @RequestParam(name = "p", defaultValue = "1") int pageNumber) { 

    Page<StatusUpdate> page = statusUpdateService.getPage(pageNumber); 

    for(StatusUpdate statusUpdate: page){ 

     SiteUser siteUser= statusUpdate.getSiteUser(); 

     modelAndView.getModel().put("siteuser", siteUser); 

     int countComments = commentService.countStatusComments(statusUpdate); 

     modelAndView.getModel().put("commentscounter", countComments); 
    } 

    modelAndView.getModel().put("page", page); 

    modelAndView.setViewName("app.viewStatus"); 

    return modelAndView; 
} 

這裏是控制檯結果：

!!!!!! STATUSUPDATECONTROLLER：viewOneStatus：Count del comment：2 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 98，title = Title97，text = Status update 97，added = 2017-06-28 12：52：04.0，siteUser = SiteUser [id = 1，email=test@caveofprogramming.com，plainPassword = null，password = $ 2a $ 10 $ TlfLjCcq8vPZHYkWcZ4rwurnqx5/g5C.5nk3hGTdiG6/cxlx1COPq，enabled = true，firstname = Mike，surname = River，repeatPassword = null，role = ROLE_ADMIN]] 2017-03-24 21:00:00 23.278 DEBUG 1080 --- [nio-8080-exec-6] org.hibernate.SQL：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：Count del comment：1 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 97，title = Title96，text =狀態更新96，增加= 2017-06-27 12：52：04.0，siteUser = SiteUser [id = 1，email = test@caveofprogramming.com，plainPassword = null，password = $ 2a $ 10 $ TlfLjCcq8vPZHYkWcZ4rwurnqx5/g5C.5nk3hGTdiG6/cxlx1COPq，enabled = true，firstname = Mike，surname = River，repeatPassword = null，role = ROLE_ADMIN]] 2017-03-24 21：00：23.280 DEBUG 1080 --- [nio-8080-exec-6] org.hibernate.SQL：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：計數刪除評論：0 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 96，title = Title95，text =狀態更新95，增加= 2017-06-26 12：52：04.0，siteUser = SiteUser [id = 1，email=test@caveofprogramming.com，plainPassword = null，password = $ 2a $ 10 $ TlfLjCcq8vPZHYkWcZ4rwurnqx5/g5C.5nk3hGTdiG6/cxlx1COPq，enabled = true，firstname = Mike，surname = River，repeatPassword = null，role = ROLE_ADMIN]] 2017-03-24 21：00：23.282 DEBUG 1080 --- [nio-8080-exec-6] org.hibernate.SQL：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：計數刪除評論：0 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 95，title = Title94，text =狀態更新94，增加= 2017-06-25 12：52：04.0，siteUser = SiteUser [id = 1，email = test@caveofprogramming.com，plainPassword = null，password = $ 2a $ 10 $ TlfLjCcq8vPZHYkWcZ4rwurnqx5/g5C.5nk3hGTdiG6/cxlx1COPq，enabled = true，firstname = Mike，surname = River，repeatPassword = null，role = ROLE_ADMIN]] 2017-03-24 21：00：23.284 DEBUG 1080 --- [nio-8080-exec-6] org.hibernate.SQL：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select count（comment0_.id）as col_0_0_ from comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!!STATUSUPDATECONTROLLER：viewOneStatus：計數德爾評論：0

這裏是JSP：

<table class="table table-hover">        
    <c:forEach var="statusUpdate" items="${page.content}"> 
     <tr> 
      <td> 
       <ul class="list-inline posted-info"> 
        <li>By 
         <a href="${contextRoot}/profile/${statusUpdate.siteUser.id}"> 
          ${statusUpdate.siteUser.firstname} 
          ${statusUpdate.siteUser.surname} 
         </a> 
        </li> 
        <li>Posted</li> 
        <li> 
         <fmt:formatDate pattern="EEEE d MMMM y 'at' H:mm:ss" value="${statusUpdate.added}" /> 
        </li> 
       </ul> 
      </td> 
     </tr> 
     <tr> 
      <td> 
       <h2> 
        <a href="${contextRoot}/viewonestatus/${statusUpdate.id}">${statusUpdate.title}></a> 
       </h2> 
       <p>${statusUpdate.text}</p> 
      </td> 
     </tr> 
     <tr> 
      <td> 
       <ul class="post-shares"> 
        <li> 
         <a href="#"> <i class="rounded-x icon-speech"></i> 
          <span>${commentscounter}</span> 
         </a> 
        </li> 
        <li><a href="#"><i class="rounded-x icon-share"></i></a></li> 
        <li><a href="#"><i class="rounded-x icon-heart"></i></a></li> 
       </ul> 
      </td> 
     </tr>     
    </c:forEach>         
</table> 

這裏來的結果（0所有的意見時，是不正確的）：

Answer 1

問題是如何將commentscouner添加到模型中。

for(StatusUpdate statusUpdate: page){ 
    SiteUser siteUser= statusUpdate.getSiteUser(); 
    modelAndView.getModel().put("siteuser", siteUser); 
    int countComments = commentService.countStatusComments(statusUpdate); 

    // next line is a cause of problem 
    modelAndView.getModel().put("commentscounter", countComments); 
} 

每當您使用相同名稱設置新值時：commentscouner。因此，每次覆蓋上一次迭代循環中添加的值時。這意味着當循環結束時，模型將包含最後一個值countComments。如果上一個值爲0，則JSP將爲所有記錄輸出0。

因此，您必須分別存儲每個StatusUpdate的評論數。例如，在圖中：現在

HashMap<StatusUpdate, Integer> counterMap = new HashMap<StatusUpdate, Integer>(); 

for(StatusUpdate statusUpdate: page){ 
    ... 
    int countComments = commentService.countStatusComments(statusUpdate);  
    counterMap.put(statusUpdate, countComments); 
} 
modelAndView.put("counterMap", counterMap); 

，在JSP中你可以在地圖的輸出值：

<table class="table table-hover">        
    <c:forEach var="statusUpdate" items="${page.content}"> 
     ... 
     <tr> 
      <td> 
       <ul class="post-shares"> 
        <li> 
         <a href="#"> 
          <i class="rounded-x icon-speech"></i> 
          <span>${counterMap[statusUpdate]}</span> 
         </a> 
        </li> 
        <li><a href="#"><i class="rounded-x icon-share"></i></a></li> 
        <li><a href="#"><i class="rounded-x icon-heart"></i></a></li> 
       </ul> 
      </td> 
     </tr>     
    </c:forEach>         
</table>