Question

我有一个控制器可以从数据库中获取所有新闻，同时它会计算每条新闻的评论数量，但是我有一个问题，因为即使数据被正确地从数据库中拉出来也是如此，jsp不会将每个新闻对象与其对应的评论计数混合......

这是我的控制器：

@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;
}

以下是控制台结果：

!!!!!! 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，密码= $ 2a $ 10 $ TlfLjCcq8vPZHYkWcZ4rwurnqx5 / g5C.5nk3hGTdiG6 / cxlx1COPq，enabled = true，firstname = Mike，surname = River，repeatPassword = null，role = ROLE_ADMIN]] 2017-03-24 21：00：23.278 DEBUG 1080 --- [nio-8080-exec-6] org.hibernate.SQL：选择count（comment0_.id）作为col_0_0_来自评论comment0_左外连接status_update statusupda1_ on comment0_。 statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select comment（comment0_.id）as col_0_0_ from comments 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 = Status update 96，added = 2017-06-27 12：52：04.0，siteUser = SiteUser [id = 1，email = test@caveofprogramming.com，plainPassword = null，密码= $ 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：选择count（comment0_.id）作为col_0_0_来自评论comment0_左外连接status_update statusupda1_ on comment0_。 statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select comment（comment0_.id）as col_0_0_ from comments comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：Count del comment：0 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 96，title = Title95，text = Status update 95，added = 2017-06-26 12：52：04.0，siteUser = SiteUser [id = 1，email = test@caveofprogramming.com，plainPassword = null，密码= $ 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 comment（comment0_.id）as col_0_0_ from comments comment0_ left outer join status_update statusupda1_ on comment0_。 statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select comment（comment0_.id）as col_0_0_ from comments comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：Count del comment：0 !!!!! VIEWSTATUS statusUpdate：StatusUpdate [id = 95，title = Title94，text = Status update 94，added = 2017-06-25 12：52：04.0，siteUser = SiteUser [id = 1，email = test@caveofprogramming.com，plainPassword = null，密码= $ 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 comment（comment0_.id）as col_0_0_ from comments comment0_ left outer join status_update statusupda1_ on comment0_。 statusupdateid = statusupda1_.id where statusupda1_.id =？ Hibernate：select comment（comment0_.id）as col_0_0_ from comments comment0_ left outer join status_update statusupda1_ on comment0_.statusupdateid = statusupda1_.id where statusupda1_.id =？ !!!!!! STATUSUPDATECONTROLLER：viewOneStatus：Count del comment：0

这是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>

结果出现了（所有评论都为0时）：

Answer 1

问题是如何将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);
}

每次使用相同名称设置新值时：commentscouner。因此，每次重写上一次迭代循环时添加的值。这意味着当循环完成时，模型将只包含countComments的最后一个值。如果最后一个值为0，则JSP将为所有记录输出0。

因此，您必须分别存储每个StatusUpdate的评论数。例如在地图中：

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);

现在，在JSP中，您可以输出地图的值：

<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>

如何在jsp结果中链接两个对象？

1 个答案: