jsp+sql实现分页

使用jdbc连接技术，将数据库中的数据进行分页
首先dao 层

//求出总共有多少页
public int getPageCount(int pagesize) {
        int pagecount=0;
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Connection conn=null;
        PreparedStatement psmt=null;
        ResultSet rs=null;
        try {
            conn=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/schools?useUnicode=true&"
                    + "characterEncoding=GBK", "root", "123456");
            String sql="select count(*) from score ";
            psmt=conn.prepareStatement(sql);
            rs=psmt.executeQuery();
            while(rs.next()) {
                int rowcount=rs.getInt(1);
                pagecount=(int)Math.ceil(1.0*rowcount/pagesize);
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            try {
                rs.close();
                psmt.close();
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        return pagecount;
    }
    //求出总共有多少数据
    public ArrayList getPageStu(int pageno,int pagesize) {
        ArrayList stus=new ArrayList<>();
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Connection conn=null;
        PreparedStatement psmt=null;
        ResultSet rs=null;
        try {
            conn=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/schools?useUnicode=true&"
                    + "characterEncoding=GBK", "root", "123456");
            String sql="select ban,bname from score limit ?,? ";
            psmt=conn.prepareStatement(sql);
            psmt.setInt(1,(pageno-1)*pagesize);
            psmt.setInt(2, pagesize);
            rs=psmt.executeQuery();
            while(rs.next()) {
                Student student=new Student(rs.getInt(1), rs.getString(2));
                stus.add(student);
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            try {
                rs.close();
                psmt.close();
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return stus;
    }

service层

StudenDao sd=new StudenDao();
public int getPageCount(int pagesize) {
        return sd.getPageCount(pagesize);
    }
    public ArrayList getPageStu(int pageno,int pagesize) {
        return sd.getPageStu(pageno, pagesize);
    }

servlet

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int pageno=1;
        if(request.getParameter("pageno") != null) {
            pageno=Integer.parseInt(request.getParameter("pageno"));
        }
        StudentService ss=new StudentService();
        int pagecount=ss.getPageCount(100);//pagesize设为每页显示100条
        ArrayList stus=ss.getPageStu(pageno, 100);
        int currentpage=pageno;
        request.setAttribute("currentpage", currentpage);
        request.setAttribute("stus", stus);
        request.setAttribute("pagecount", pagecount);//总共有多少页
        int pageprev=pageno>1?pageno-1:1;//上一页
        int pagenext=pageno1:pagecount;//下一页
        request.setAttribute("pagenow", pageno);//当前页
        request.setAttribute("pageprev", pageprev);
        request.setAttribute("pagenext", pagenext);
        request.getRequestDispatcher("main.jsp").forward(request, response);
    }

jsp页面

        <table border="1" cellpadding="0" cellspacing="0" style="width: 500px;text-align:center;border-color: #ccc">
                <tr id="cs">
                    <td>班级td>
                    <td>姓名td>
                tr>
                 <c:forEach items="${stus }" var="stu">
                        <tr>
                            <td>${stu.ban }td>
                            <td>${stu.name }td>
                        tr>
                c:forEach> 
             table>

<div id="dic">
    <ul>
        <li><a href="PageServlet?pageno=1">首页a>li>
        <li><a href="PageServlet?pageno=${pageprev }">上一页a>li>
        <li><a href="PageServlet?pageno=${pagenext }">下一页a>li>
        <li><a href="PageServlet?pageno=${pagecount }">尾页a>li>
    ul>
    div>
    <form action="PageServlet" method="get" id="f1">
        <p>跳转至：
        <c:forEach begin="1" end="${pagecount }" var="i">
                    <c:if test="${pagenow == i }">
                       <input type="text" name="pageno" value="${i }">页
                    c:if>

            c:forEach>

                <input type="submit" value="跳转">
        p>
    form>