Java front and back page

In the background page write get in the action

public void GetPatrolMission(){
		Session dbSession = HibernateSessionFactory.getSession();
		try {
			
			int page=this.ConvertObjToInt(this.GetParam("page"));
			int rows=this.ConvertObjToInt(GetParam("rows"));
			String hqlStr="from PsPatrolMission";
			Query aQuery= dbSession.createQuery(hqlStr);
			
			int count=aQuery.list().size();
			
			aQuery.setFirstResult((page-1)*rows);
			aQuery.setMaxResults((page)*rows);
			List AllPatrolMission =aQuery.list();
			JsonConfig jsonConfig = new JsonConfig();  //建立配置文件
			jsonConfig.setIgnoreDefaultExcludes(false);  //设置默认忽略
			jsonConfig.registerJsonValueProcessor(Timestamp.class,new com.ps.utility.JsonDateValueProcessor());
			jsonConfig.setExcludes(new String[]{""});  
			String json = JSONArray.fromObject(AllPatrolMission,jsonConfig).toString();
			
			json = "{\"page\":\"" + page + "\", \"total\":" + count + ",\"records\":\"" +AllPatrolMission.size() + "\",\"rows\": " + json + "}";
			json = json.replace("\n", "").replace("\t", "").replace("\r", "");
		    ReturnMessage(json);
		}catch(Exception ex){
			ReturnMessage("FAILD:"+ex.getMessage());
		}finally{
			dbSession.disconnect();dbSession.close();
		}	
	}

Front page write in the loading table load function in

 function loadDatagrid() {
    	$('#CameraModelInfo').datagrid('loadData', { total: 0, rows: [] });
    	$.ajax
		({ 
			type: "GET", 
			url: "GetModelInfo.action",
			onDblClickRow:CameraModelInfoClick,
			success: function(sCameraModelInfo)
			{ 	
				var data = [];
				var obj = eval("("+sCameraModelInfo+")");
				for(var i=0; i<obj.length; i++){
     				var row = {"ID":obj[i].id,"BRAND":obj[i].brand,
						"MODEL":obj[i].model,"TYPE":obj[i].type,
						"ANGLE":obj[i].angle,"MAXFOCAL":obj[i].maxfocal,
						"MINFOCAL":obj[i].minfocal,"CCDWIDTH":obj[i].sensorwidth,
						"CCDHEIGHT":obj[i].sensorheight};

					data.push(row);
				}
				
				function pagerFilter(data){
		            if (typeof data.length == 'number' && typeof data.splice == 'function'){    // is array
		                data = {
		                    total: data.length,
		                    rows: data
		                }
		            }
		            
		            var dg = $(this);
		            var opts = dg.datagrid('options');
		            var pager = dg.datagrid('getPager');
		            pager.pagination({
		                onSelectPage:function(pageNum, pageSize){
		                    opts.pageNumber = pageNum;
		                    opts.pageSize = pageSize;
		                    pager.pagination('refresh',{
		                        pageNumber:pageNum,
		                        pageSize:pageSize
		                    });
		                    dg.datagrid('loadData',data);
		                }
		            });
		            if (!data.originalRows){
		                data.originalRows = (data.rows);
		            }
		            var start = (opts.pageNumber-1)*parseInt(opts.pageSize);
		            var end = start + parseInt(opts.pageSize);
		            data.rows = (data.originalRows.slice(start, end));
		            return data;
		        }
		        
		        $(function(){
		            $('#CameraModelInfo').datagrid({loadFilter:pagerFilter}).datagrid('loadData', data);
		            $('#CameraModelInfo').datagrid('getPager').pagination({  
		                pageSize: 20,  
		                pageNumber: 1,  
		                pageList: [10, 20, 30, 40, 50],  
		                beforePageText: '第',//页数文本框前显示的汉字   
		                afterPageText: '页    共 {pages} 页',  
		                displayMsg: '当前显示 {from} - {to} 条记录   共 {total} 条记录',  
		           });
		        });
			}
		});
    }