JSF中自定义的分页标签的研究

最新推荐文章于 2025-08-11 11:09:48 发布

原创最新推荐文章于 2025-08-11 11:09:48 发布 · 601 阅读

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#jsf #string #query #list #javascript #null

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本文介绍了一种基于JSF的分页实现方案，通过PaginationTag标签和ListChunk对象完成分页逻辑。PaginationTag标签负责分页显示及交互，而ListChunk则用于处理数据分页。文章详细解释了PaginationTag的实现原理及其与ListChunk之间的交互过程。

分页标签的研究：
    <tag>
      <name>pagination</name>
      <tag-class>com.pp.condition.PaginationTag</tag-class>
      <attribute>
        <name>sortColumns</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
      </attribute>
      <attribute>
        <name>sortTable</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
      </attribute>
   </tag>

<c:forEach var="consultProject" items="#{listChunk.list}">

PaginationTag.java
继承TagSupport
有如下方法
doStartTag() 标签的开始
{init();...}

与listchunk的关联，获得相关的值
    private void init() throws JspException {
        writer = pageContext.getOut();

        // 获得ListChunk对象
        listChunk=(ListChunk)FacesUtils.getManagedBean("listChunk");
//        UIViewRoot viewRoot=FacesContext.getCurrentInstance().getViewRoot();

        curPage=listChunk.getCurPage();
        // 获得当前页显示多少条的信息
        if (pageSizeName == null) {
            pageSizeName = PAGE_SIZE;
        }
        pageSize = listChunk.getPageSize();

        // 获得总记录数
        totalRecord = listChunk.getTotalCount();
        //当前页的记录数目
//        curRecord = listChunk.getCurrentCount();
        // 获得总页数
        totalPage = listChunk.getTotalPage();

        SearchConditions searchConditions=(SearchConditions)FacesUtils.getManagedBean("searchConditions");
        sortColumn=searchConditions.getCondition("sortColumn");
        sortOrder=searchConditions.getCondition("sortOrder");

        // 当listChunk个数为零时，要能显示第1页
        if (listChunk.getTotalCount() == 0) {
            totalPage = 1;
        }

        // 获得当前页码
        if (curPageName == null) {
            curPageName = CUR_PAGE;
        }
    }
doendTag()    标签的结束

searchForm规定了吗？是的,可以看PaginationTag.java中定义的javascript中有searchForm

使用

<h:form id="searchForm">
<c:forEach var="my" items="#{listChunk.list}">

每一块dao 的listchunk（）
getObjectsPaginate(query, paramMap);
public ListChunk getObjectsPaginate(Query query, Map paramMap){
    ListChunk listChunk=(ListChunk)FacesUtils.getManagedBean("listChunk");
    int curPage=listChunk.getCurPage();
    int pageSize=listChunk.getPageSize();
    if(curPage<=0)
    {
      curPage=1;
      listChunk.setCurPage(curPage);
    }
    if(pageSize<=0)
    {
      pageSize=10;
      listChunk.setCurPage(pageSize);
    }
        String queryString = query.getQueryString();
        String[] param = query.getNamedParameters();
        String fromClause = null;
        int fromClausePos = queryString.toLowerCase().indexOf("from");
        int count = 0;
        if (fromClausePos >= 0) {
            fromClause = queryString.substring(fromClausePos);
            int orderPos = fromClause.toLowerCase().lastIndexOf("order by");
            if(orderPos >= 0) {
                fromClause = fromClause.substring(0, orderPos);
            }
            String countHql = "select count(*) " + fromClause;
            Query countQuery = getSession().createQuery(countHql);
            for (int i = 0; i < param.length; i++) {
                countQuery.setParameter(param[i], paramMap.get(param[i]));
            }
            final Object cnt = countQuery.uniqueResult();
            count = ((Long)cnt).intValue();
        }
        for (int i = 0; i < param.length; i++) {
            query.setParameter(param[i], paramMap.get(param[i]));
        }
        int tempCount = (curPage - 1) * pageSize;
        query.setFirstResult(tempCount);
        query.setMaxResults(pageSize);
        List list = query.list();
        listChunk.setList(list);
        listChunk.setTotalCount(count);
        return listChunk;
    }

<managed-bean>
  <managed-bean-name>listChunk</managed-bean-name>
  <managed-bean-class>
   com.whlongyi.common.condition.ListChunk
  </managed-bean-class>
  <managed-bean-scope>request</managed-bean-scope>
  <managed-property>
   <property-name>pageSize</property-name>
   <value>
    #{param['pageSize']==null?10:param['pageSize']} 
   </value>
  </managed-property>

  <managed-property>
   <property-name>curPage</property-name>
   <value>#{param['curPage']==null?1:param['curPage']}</value>
  </managed-property>
</managed-bean>

附件：

csdn空间5/jsf中分页的使用.rar