ext grid 数据库分页实现

看了robbin 关于hibernate 分页的老帖(http://www.iteye.com/topic/261)，把ext grid 的数据库分页整了下，完全满足需要，呵呵，贴出代码与大家共同学习下：
  DAO代码：
 

  /**
       * 获取符合查询条件的记录总数
       * @param detachedCriteria  hibernate Criteria 查询对象，由service组装
       * @return
       */
  public Long getRecordCount(final DetachedCriteria detachedCriteria) {
        return (Long) getHibernateTemplate().execute(new HibernateCallback() {
            public Object doInHibernate(Session session)
                    throws HibernateException {
                Criteria criteria = detachedCriteria
                        .getExecutableCriteria(session);
                long count = Long.parseLong((criteria.setProjection(Projections
                        .rowCount()).uniqueResult()).toString());
                criteria.setProjection(null);
                return Long.valueOf("" + count);
            }
        }, true);
    }
/**
       * 获取符合条件的查询记录
       * @param detachedCriteria
       * @param startResult
       * @param limitResult
       * @return
       */

    public List listByConditions(final DetachedCriteria detachedCriteria,
            final int startResult, final int limitResult) {

        return (List) getHibernateTemplate().execute(new HibernateCallback() {
            public Object doInHibernate(Session session)
                    throws HibernateException {
                Criteria criteria = detachedCriteria
                        .getExecutableCriteria(session);
                criteria.setFirstResult(startResult);
                criteria.setMaxResults(limitResult);
                return criteria.list();
            }
        }, true);
    }

服务层：

/**
     * 获取所有日志列表
     * @param startResult   查询记录起点
     * @param limitResult   简要列表每页最大记录数
     * @param sortRecord    简要列表排序字段名
     * @param dirRecord     简要列表排序类型 DESE/ASC
     * @return
     */
public JSONArray getAllLogs(String startResult,String limitResult,
              String sortRecord,String dirRecord) {

        try {
            DetachedCriteria detachedCriteria = DetachedCriteria.forClass(TDeasLog.class);
            if(dirRecord.equals("ASC"))
                detachedCriteria.addOrder(Order.asc(sortRecord));
            else
                detachedCriteria.addOrder(Order.desc(sortRecord));

            Long count = logDAO.getRecordCount(detachedCriteria);//获取符合条件的记录总数

            List list = logDAO.listByConditions(detachedCriteria, Integer.parseInt(startResult),
                      Integer.parseInt(limitResult));//获取符合条件记录
            if(list.size()>0){
                List jsonlist = new ArrayList();
                Iterator it = list.iterator();
                while (it.hasNext()){
                    Log log = (Log )it.next();
                    Map map = new HashMap();
                    map.put("taskId", log .getTaskId());
                    map.put("rwfssj", log .getRwfssj());
                    map.put("rwjssj", log .getRwjssj());
                            ....
                    jsonlist.add(map);
                }
                Map m = new  HashMap();
                m.put("results", count.toString());
                m.put("rows", jsonlist);

                JSONArray jsonArray = JSONArray.fromObject(m);
                return jsonArray;
            }else
                return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

  action 代码：

public ActionForward getAllLogs(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) {

        String startResult = request.getParameter("start");
        String limitResult = request.getParameter("limit");
        String sortRecord = request.getParameter("sort");
        String dirRecord = request.getParameter("dir");

        JSONArray jsonArray = this.getLogService().getAllLogs(startResult,limitResult,sortRecord,dirRecord);

        if(jsonArray != null){
            String jsonstr = jsonArray.toString();
            //去除JSON对象前的[]
            String json = jsonstr.substring(1, jsonstr.length()-1);
            response.setContentType("text/json; charset=utf-8");
            try {
                response.getWriter().print(json);
            } catch (IOException e) {
                log.error("获取日志实例列表失败，异常："+e.getMessage());
            }
        }else{//返回空数据，格式：{"rows":[],"results":"0"}
            List list = new ArrayList();
            Map map1 = new HashMap();
            list.add(map1);
            Map m = new  HashMap();
            m.put("results", "0");
            m.put("rows", list);
            JSONArray json = JSONArray.fromObject(m);
            String jsonString = json.toString();
            String jsonstr =jsonString.substring(1, jsonString.length()-1);
            response.setContentType("text/json; charset=utf-8");
            try {
                response.getWriter().print(jsonstr);
            } catch (IOException e) {
                log.error("获取日志实例列表失败，异常："+e.getMessage());
            }
        }
        return null;
    }

 

开始无数据时怎么也不能显示PagingToolbar 的emptyMsg，后来发现空数据时组织格式错误，忘记去掉 [{"rows":[],"results":"0"}]这部分的“[]”，这个小问题折磨了俺好久，呵呵，要细心啊～！

JS代码：

  var datastore = new Ext.data.Store({
       proxy: new Ext.data.HttpProxy({
           url: 'logManage.do?method=getAllLogs'
       }),
       reader: new Ext.data.JsonReader({
        root               : 'rows',
           totalProperty      : 'results',
           id: 'taskID'
       }, [
           {name: 'taskId'},
           {name: 'rwfssj'},
           {name: 'rwjssj'},
           ....
       ]),
        remoteSort: true
   });
   datastore.setDefaultSort('taskId','ASC');
   datastore.load({params:{start:0, limit:10}});

var sm = new Ext.grid.CheckboxSelectionModel();
var colModel = new Ext.grid.ColumnModel([
    new Ext.grid.RowNumberer(),
    { header:'任务ID', width:100, sortable:true, locked:true, dataIndex:'taskId'},
    { header:'任务类型', width:100, sortable:true, locked:false, dataIndex:'rwlb'},
    { header:'任务状态', width:100, sortable:true, locked:false, dataIndex:'rwzt'},
    ......
]);

var LogGrid = new Ext.grid.GridPanel({
    ds                  : datastore,
    cm                  : colModel,
    sm                  : sm,
    id                  : 'LogGrid',
    title               : '日志列表',
    autoHeight          : true,
       width               : '100%',
       loadMask            : true,
     buttons            : [{
            text        : '查询',
            tooltip     : '日志查询',
            handler     : logSearch
     },{
            text        : '关闭',
            tooltip     : '关闭窗口',
            handler     : closeForm
     }],
       buttonAlign         : 'right',
       bbar                : new Ext.PagingToolbar({
           id              : 'pagingbar',
           pageSize        : 10,
           store           : datastore,
           displayInfo     : true
            })
});

   搞定，收工....