struts+hibernate中分页显示的示例

1.我们以一个药品管理系统为例,当点击查看所有药品的时候,(项目开发>医药管理系统)

baseData/med.do?command=paging

此时struts配置文件为将此请求发送到指定action中:

public class MedicineAction extends DispatchAction {
             //要用dispatchAction因为请求中指定了方法                      

             protected int recPerPage = 3; // 分页中每页的记录数

    // 分页查询药品信息
                public ActionForward paging(ActionMapping mapping, ActionForm form,
                               HttpServletRequest request, HttpServletResponse response)  throws Exception {
                        // 获取页码
                          String currPage = request.getParameter("currPage");\\从页面中穿过来的当前页码
                        // 构建action地址
                          String action = request.getContextPath() + "/baseData/med.do?command=paging";
                          // HQL查询语句
                              String hql = "from Medicine";
                        // 分页查询,返回Map对象
                            Map map = this.getPage(hql, recPerPage, currPage, action, null);
                          //将结果集放到request中
                               request.setAttribute("list", map.get("list"));
                        //将结果集放到分页条中
                            request.setAttribute("pagingBar", map.get("bar"));
                          return mapping.findForward("findAllSuccess");
                 }   

 

             public Map getPage(String hql, int recPerPage, String currPage,
                                                          String action, Object[] where) {
                      // 实例化一个Map对象
                    Map map = new HashMap();
                    // 分页条
                     StringBuffer pagingBar = new StringBuffer();
                     List list = null; // 结果集
                  int iCurrPage = 1; // 当前页码
                      // 如果传递了页码则对当前页码赋值
                 if (currPage != null && !currPage.isEmpty()) {
                  iCurrPage = Integer.parseInt(currPage);
                 }
                 // 实例化SupperDao对象
                 SupperDao dao = new SupperDao();
                  int pages = 0; // 总页数
                  // 获取总记录数
                 Long l = (Long) dao.uniqueResult("select count(*) " + hql, where);
                   int count = l.intValue(); // 将总记录数转为int型
                if (count > 0) {
                         // 计算总页数
                         if (count % recPerPage == 0) {
                                    pages = count / recPerPage;
                        } else {
                                     pages = count / recPerPage + 1;
                         }
                        if (iCurrPage > pages) {
                                     iCurrPage = pages;
                         }
                        if (iCurrPage < 1) {
                                     iCurrPage = 1;
                         }
                        // 分页查询获取结果集
                        list = dao.findPaging(hql, (iCurrPage - 1) * recPerPage,recPerPage, where);
                        // 构造分页条
                          pagingBar.append("<form name='pagingForm' action='" + action
                                                         + "' method='post'>");
                          // 在分页条中添加总记录数
                           pagingBar.append("totalRecord"+ count);
                           pagingBar.append(" ");
                            pagingBar.append("total" + " "+ pages + " " + "page");
                           pagingBar.append(" ");
                           // 页数大于1显示上一页超链接,否则不显示超链接
                           if (iCurrPage > 1) {
                           pagingBar.append("<a href=" + action + "&currPage=1>" + "first" + "</a>");
                            pagingBar.append(" ");
                            pagingBar.append("<a href=" + action + "&currPage="+ (iCurrPage - 1) + ">"
                                         +  "previous" + "</a>");
                             pagingBar.append(" ");
                          } else {
                                      pagingBar.append( "first");
                                       pagingBar.append(" ");
                                       pagingBar.append("previous");
                                       pagingBar.append(" ");
                           }
                           // 显示当前页码
                           pagingBar.append("<font color='red'>" + iCurrPage + "</font>");
                           pagingBar.append(" ");
                           // 页数小于总页数显示下一页超链接,否则不显示超链接
                           if (iCurrPage < pages) {
                                  pagingBar.append("<a href=" + action + "&currPage="
                                              + (iCurrPage + 1) + ">"+  "next" + "</a>");
                                  pagingBar.append(" ");
                                   pagingBar.append("<a href=" + action + "&currPage=" + pages+ ">" + "last"+ "</a>");
                           } else {
                                    pagingBar.append( "next");
                                    pagingBar.append(" ");
                                    pagingBar.append("last");
                           }
                           pagingBar.append(" ");
                           pagingBar.append("<input type='text' name='currPage' size='1'>");
                           pagingBar.append("<input type='submit' value='GO'>");
                           pagingBar.append("</form>");
                  }
                   map.put("list", list);// 结果集
                   map.put("bar", pagingBar.toString());// 分页条的字符串形式
                   return map;
         }
}
 上面涉及到了两个黑体字的方法,如下:

          public Object uniqueResult(String hql,Object[] where){
                  Object obj = null;
                   try {
                           session = HibernateFilter.getSession(); //获取Session对象
                           session.beginTransaction(); //开启事物
                           Query query = session.createQuery(hql); //创建Query对象
                           //如果where不为空,则对HQL语句进行动态赋值
                           if(where != null && where.length > 0){
                                 for (int i = 0; i < where.length; i++) {
                                 if(where[i] != null){
                                      query = query.setParameter(i, where[i]);
                                 }
                                 }
                           }
                            obj = query.uniqueResult(); //单值检索
                             session.getTransaction().commit(); //提交事物
                           } catch (Exception e) {
                               e.printStackTrace(); //打印异常信息
                                 session.getTransaction().rollback(); //回滚事物
                            }
                                  return obj;
                       }

             public List findPaging(String hql,int offset,int length,Object[] where){
                     List list = null;
                    try {
                          session = HibernateFilter.getSession();//获取Session对象
                            session.beginTransaction(); //开启事物
                          Query query = session.createQuery(hql); //创建Query对象
                          //构建查询条件
                         if(where != null && where.length > 0){
                                for (int i = 0; i < where.length; i++) {
                                      if(where[i] != null){
                                           query = query.setParameter(i, where[i]);
                                        }
                                 }
                           }
                           list = query.setFirstResult(offset) //设置起始位置
                                            .setMaxResults(length) //偏移量
                                             .list(); //获取结果集
                           session.getTransaction().commit(); //提交事物
                     } catch (Exception e) {
                             e.printStackTrace(); //打印异常信息
                               session.getTransaction().rollback(); //回滚事物
                       }
                       return list;
            }

分页显示的目标页面应如下:

<table border="1" align="center" width="700" >
    <tr >
       <td ><bean:message key="delete" /></td>
       <td ><bean:message key="id" /></td>
       <td ><bean:message key="medNo" /></td>
       <td ><bean:message key="name" /></td>
   </tr>
       <logic:present name="list" scope="request">
          <logic:notEmpty name="list" scope="request">
              <form action='<html:rewrite page="/baseData/deleteMedicineAction.do"/>'  method='post'>
                     <logic:iterate id="ele" name="list" scope="request">
                          <tr>
                               <td>
                                    <input type="hidden" name="allId" value='<bean:write name="ele" property="id" />'>//增加了删除此条记录的功能,此处不多记录
                                    <input type="checkbox" name="selectedId" value='<bean:write name="ele" property="id" />'>
                              </td>
                              <td><bean:write name="ele" property="id"/></td>
                              <td><bean:write name="ele" property="medNo"/></td>
                              <td>
                                   <html:link href="med.do?command=view" paramId="id" paramName="ele" paramProperty="id">
                                          <bean:write name="ele" property="name"/>
                                   </html:link>\\此句功能为点击药品名就可以打开此药品的详细页面
                              </td>
                          </tr>
                     </logic:iterate>
                     <tr>
                         <td>
                               <table border="0" width="100%">
                                     <tr>
                                         <td>
                                               <html:submit property="command">deleteSelected</html:submit>
                                               <html:submit property="command">deleteAll</html:submit>
                                        </td>
                </form>

                     <td align="right">
                         <logic:present name="pagingBar" scope="request">
                              <bean:write name="pagingBar" filter="false" scope="request"/>
                         </logic:present>
                    </td>
               </tr>
          </table>
      </td>
  </tr>
</logic:notEmpty>
</logic:present>
</table>

 

             

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