运用EasyUI中datagrid读取数据库数据实现分页

package com.hanqi.dao;

import java.util.ArrayList;

import java.util.List;

import org.hibernate.Query;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import com.han.entity.Student;

public class StudentDAO {

    //定义变量

    Configuration cfg = null ;

    ServiceRegistry sr = null ;

    SessionFactory sf = null ;

    Session se = null ;

    Transaction ts = null ;

    //构造方法

    public StudentDAO()

    {

        //1获取配置文件

        cfg = new Configuration().configure() ;

        //2注册配置

        sr = new StandardServiceRegistryBuilder().

                                            applySettings(cfg.getProperties()).build();

    }

    //初始化方法

    private void init()

    {

        //3获取SessionFactory

        sf = cfg.buildSessionFactory(sr) ;

        //4产生Session

        se =sf.openSession() ;

        //5启动事务

        ts = se.beginTransaction() ;

    }

    //关闭释放资源

    private void destroy()

    {

        ts.commit();  //提交事务

        se.close() ;//关闭释放资源

        sf.close();//关闭释放资源

    }

    //获取分页数据集合

    public List<Student> getPageList(int page, int rows)

    {

        List<Student> list = new ArrayList<>() ;//定义list变量并实例化

        init() ;//初始化方法

        list = se.createQuery("from Student")

                     .setMaxResults(rows)//每页行数

                     .setFirstResult((page-1)*rows)//起始页码

                     .list() ;

        destroy() ;//关闭释放资源

        return list ;//返回该集合

    }

    //获取数据条数

    public int getTotal()

    {

        int rtn = 0 ;//定义变量并赋值

        init() ;//初始化方法

        Query qu = se.createQuery("select count(1) from Student ") ;//获取Query对象

        List<Object> list = qu.list() ;//定义list变量并实例化

        if(list != null && list.size() > 0 )//判断获取的集合非空及长度

        {

            rtn = Integer.parseInt(list.get(0).toString()) ;//给变量rtn赋值

        }

        destroy();//关闭并释放资源

        return rtn ;//返回变量值

    }

}

package com.hanqi.service;

import java.util.List;

import com.alibaba.fastjson.JSONArray;

import com.han.entity.Student;

import com.hanqi.dao.StudentDAO;

public class StudentService {

    //查询分页数据，并返回JSON

    public String getPageJSON(int page, int rows)

    {

        String rtn = "{'total':0,'rows':[ ]}" ;

        int total =  new StudentDAO().getTotal() ;

        if(total > 0)

        {

            List<Student> list =  new StudentDAO().getPageList(page, rows) ;

            //将List集合转为JSON集合

            String json_list = JSONArray.toJSONString(list) ;

            //转义字符返回复合类型的JSON字符串

            rtn =  "{\"total\":"+total+",\"rows\":"+json_list+"}" ;

        }

        return rtn ;

    }

}

package com.hanqi.web;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.hanqi.service.StudentService;

/**

 * Servlet implementation class StudentServlet

 */

public class StudentServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    /**

     * @see HttpServlet#HttpServlet()

     */

    public StudentServlet() {

        super();

        // TODO Auto-generated constructor stub

    }

    /**

     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        request.setCharacterEncoding("UTF-8");

        response.setCharacterEncoding("UTF-8");

        response.setContentType("text/html");

        //接收请求

            //1每页行数

        String rows = request.getParameter("rows") ;

            //2页码

        String page = request.getParameter("page") ;

        //System.out.println("rows = "+ rows );

        //System.out.println("page = " + page );

        if(page != null && rows != null)

        {

            int rowss = Integer.parseInt(rows) ;

            int pagess = Integer.parseInt(page) ;

            String json_list = new StudentService().getPageJSON(pagess, rowss) ;

            //返回数据

            System.out.println(json_list);

            response.getWriter().write(json_list) ;

        }

        else

        {

            response.getWriter().write("{total:0,rows:[]}") ;

        }

    }

    /**

     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // TODO Auto-generated method stub

        doGet(request, response);

    }

}

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>Insert title here</title>

<!-- 1    jQuery的js包 -->

<script type="text/javascript" src="jquery-easyui-1.4.4/jquery.min.js"></script>

<!-- 2    css资源 -->

<link rel="stylesheet" type="text/css" href="jquery-easyui-1.4.4/themes/default/easyui.css">

<!-- 3    图标资源 -->

<link rel="stylesheet" type="text/css" href="jquery-easyui-1.4.4/themes/icon.css"> 

<!-- 4    EasyUI的js包 -->

<script type="text/javascript" src="jquery-easyui-1.4.4/jquery.easyui.min.js"></script>

<!-- 5    本地语言 -->

<script type="text/javascript" src="jquery-easyui-1.4.4/locale/easyui-lang-zh_CN.js"></script>

</head>

<body>

<script type="text/javascript">

$(function(){

$('#dg').datagrid({

    url:'StudentServlet',

    columns:[[

        {field:'sno',title:'课程号',width:100},

        {field:'sname',title:'姓名',width:100},

        {field:'ssex',title:'性别',width:100,align:'right'},

        {field:'sbirthday',title:'生日',width:100,align:'right'},

        {field:'sclass',title:'班级',width:100,align:'right'}

    ]],

    pagination:true,//分页

    fitColumns:true,//列自适应宽度

});

})

</script>

<table id="dg"></table>

</body>

</html>