通用分页方法

来源：互联网发布：pscs6软件官方下载编辑：程序博客网时间：2024/05/19 20:43

分页大概是所有WEB程序都需要去进行的一个工作，将多条数据分成多页，不会使用户感到冗长，那么如何实现一个通用的方法，使分页更加简单，这是我们所关注的问题，话不多说，上代码。

Java代码部分

PageInfo.java 记录Page相关信息

   import java.util.List;

   public class PageInfo {
   // 传入的数据
   private int currentPage;// 当前页面的Index
   private int pageSize;// 每页所显示的数据大小
   // 从数据库中取得的数据
   private List currentPageList;// 当前页面所要显示的数据
   private int recordCount;// 总记录的数
   // 所要计算的数据
   private int beginPage;// 开始的页面的Index
   private int endPage;// 结束页面的Index
   private int pageCount;// 总的页面数

   public PageInfo() {

   }

   public PageInfo(int currentPage, int pageSize, List currentPageList,
           int recordCount) {
       super();
       this.currentPage = currentPage;
       this.pageSize = pageSize;
       this.currentPageList = currentPageList;
       this.recordCount = recordCount;
       this.pageCount = (recordCount/pageSize)+1;
       //如果总页面数小于10条,则显示前10条
       if(pageCount<10){
           this.beginPage=1;
           this.endPage=pageCount;
       }else{
       //如果总记录数大于10条
            if(currentPage-4<1){
               this.beginPage=1;
               this.endPage=currentPage+5;
            }else if(currentPage+5>pageCount){
               this.beginPage = currentPage - 4;
               this.endPage = pageCount;
            }else{
               this.beginPage=currentPage-4;
               this.endPage=currentPage+5;
            }
           //如果currentPage-4 = beginPage<1
           //如果currentPage+5 = endPage >
       }
   }

   public int getCurrentPage() {
       return currentPage;
   }

   public void setCurrentPage(int currentPage) {
       this.currentPage = currentPage;
   }

   public int getPageCount() {
       return pageCount;
   }

   public void setPageCount(int pageCount) {
       this.pageCount = pageCount;
   }

   public int getPageSize() {
       return pageSize;
   }

   public void setPageSize(int pageSize) {
       this.pageSize = pageSize;
   }

   public int getRecordCount() {
       return recordCount;
   }

   public void setRecordCount(int recordCount) {
       this.recordCount = recordCount;
   }

   public int getBeginPage() {
       return beginPage;
   }

   public void setBeginPage(int beginPage) {
       this.beginPage = beginPage;
   }

   public int getEndPage() {
       return endPage;
   }

   public void setEndPage(int endPage) {
       this.endPage = endPage;
   }

   public List getCurrentPageList() {
       return currentPageList;
   }

   public void setCurrentPageList(List currentPageList) {
       this.currentPageList = currentPageList;
   }

}

辅助拼写SQL语句的QueryHelper类

import java.util.ArrayList;
import java.util.List;

import org.qust.oa.basedaoImple.BasedaoImple;
import org.qust.oa.domain.PageInfo;

import com.opensymphony.xwork2.ActionContext;

public class QueryHelper {

   private String fromClause; // 拼接成的FROM
   private String whereClause = ""; // 拼接成的Where
   private String orderByClause = ""; // 拼接成的OrderBy

   private List<Object> parameters = new ArrayList<Object>();

   /**
   *
   *
   * @param clazz
   * @param alias
   *
   */
   public QueryHelper(Class clazz, String alias) {
       fromClause = "FROM " + clazz.getSimpleName() + " " + alias;
   }

   public QueryHelper addCondition(String condition, Object... params) {
       //
       if (whereClause.length() == 0) {
           whereClause = " WHERE " + condition;
       } else {
           whereClause += " AND " + condition;
       }

       if (params != null) {
           for (Object p : params) {
               parameters.add(p);
           }
       }

       return this;
   }

   /**
   * 筛选的条件
   *
   * @param append
   * @param condition
   * @param params
   */
   public QueryHelper addCondition(boolean append, String condition, Object... params) {
       if (append) {
           addCondition(condition, params);
       }
       return this;
   }

   /**排序的条件
   */
   public QueryHelper addOrderProperty(String propertyName, boolean asc) {
       if (orderByClause.length() == 0) {
           orderByClause = " ORDER BY " + propertyName + (asc ? " ASC" : " DESC");
       } else {
           orderByClause += ", " + propertyName + (asc ? " ASC" : " DESC");
       }
       return this;
   }

   public QueryHelper addOrderProperty(boolean append, String propertyName, boolean asc) {
       if (append) {
           addOrderProperty(propertyName, asc);
       }
       return this;
   }
     //得到当前页的记录
   public String getListQueryHql() {
       return fromClause + whereClause + orderByClause;
   }

    //得到数据的记录数
   public String getCountQueryHql() {
       return "SELECT COUNT(*) " + fromClause + whereClause;
   }

    //获取封装的参数
   public List<Object> getParameters() {
       return parameters;
   }

}
   使用QueryHelper进行查询的示例代码：
       QueryHelper qh = new QueryHelper(类名.class, "别名").addCondition(
               "别名.属性名=?", 属性值)
               .addCondition((viewType == 1), "别名.属性名=?", Topic.TYPE_BEST) // 1 表示只看精华帖
               .addOrderProperty((orderBy == 1), "别名.属性名", asc) // 1 表示只按最后更新时间排序
               .addOrderProperty((orderBy == 2), "别名.属性名", asc) // 2 表示只按主题发表时间排序
               .addOrderProperty((orderBy == 3), "别名.属性名“, asc) // 3 表示只按回复数量排序
               .addOrderProperty((orderBy == 0), "(CASE "别名.属性名“ WHEN 2 THEN 2 ELSE 0 END)", false)//
               .addOrderProperty((orderBy == 0), "别名.属性名", false);

       PageInfo pageInfo = topicService
               .findPageInfo(currentPage, pageSize, qh);

findPageInfo类代码

   public PageInfo findPageInfo(Integer currentPage, Integer pageSize,
           QueryHelper qh){
       // 参数列表
               List<Object> parameters = qh.getParameters();
               // 查询本页的数据列表
               Query listQuery = getSession().createQuery(qh.getListQueryHql()); // 创建查询对象
               if (parameters != null) { // 设置参数
                   for (int i = 0; i < parameters.size(); i++) {
                       listQuery.setParameter(i, parameters.get(i));
                   }
               }
               listQuery.setFirstResult((currentPage - 1) * pageSize);
               listQuery.setMaxResults(pageSize);
               List list = listQuery.list(); // 执行查询
               // 查询总记录数量
               Query countQuery = getSession().createQuery(qh.getCountQueryHql());
               if (parameters != null) { // 设置参数
                   for (int i = 0; i < parameters.size(); i++) {
                       countQuery.setParameter(i, parameters.get(i));
                   }
               }
               Long count = (Long) countQuery.uniqueResult(); // 执行查询
               return new PageInfo(currentPage, pageSize, list,count.intValue());
   }

通用的HTML代码

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
   
   <div id=PageSelectorBar>
       <div id=PageSelectorMemo>页次：${currentPage}/${pageCount}页  
           每页显示：${pageSize}条   总记录数：${recordCount}条</div>
       <div id=PageSelectorSelectorArea>
           <s:a href="javascript: goToPage(1)" title="首页" style="cursor: hand;">
               <img
                   src="${pageContext.request.contextPath}/style/blue/images/pageSelector/firstPage.png" />
           </s:a>
           

           <s:iterator begin="beginPage" end="endPage" var="page">
               <s:if test="#page == currentPage">
                   
                   <span class="PageSelectorNum PageSelectorSelected">${page}</span>
               </s:if>
               <s:else>
                   
                   <span class="PageSelectorNum" style="cursor: hand;"
                       onClick="goToPage('${page}');">${page}</span>
               </s:else>
           </s:iterator>

           <s:a href="javascript: goToPage(%{pageCount})" title="尾页"
               style="cursor: hand;">
               <img
                   src="${pageContext.request.contextPath}/style/blue/images/pageSelector/lastPage.png" />
           </s:a>

           转到： <select onchange="goToPage(this.value);" id="_selected">
               <s:iterator begin="1" end="%{pageCount}" var="number">
                   <option value="${number}">${number}</option>
               </s:iterator>
           </select>

           <script type="text/javascript">
                               $("#_selected").val("${currentPage}");
           </script>

       </div>
   </div>

效果图：

0 0