关于 jsp页面

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jsp页面是如何实现分页的，有具体的代码最好。

王亮 · 王亮

String sql = "select * from memberinfo order by id desc limit ?,?";  使用MySQL啊，还用Struts了啊。我来点简单的（实际项目肯定不是这样滴啊，用Oracle）[code=java]<%@ page contentType="text/html" pageEncoding="gb2312"%>
<%@ page import="java.sql.*" %>
<html>
<head><title></title>
<style type="text/css">
      
</style>
</head>
      <script language="javascript">
            function changeColor(obj,color){
                     obj.bgColor = color ;
            }
      </script>
<body>
<%!
      public static final String URL = "emp_list_true.jsp" ;
%>
<%!
      public static final String DBDRIVER = "oracle.jdbc.driver.OracleDriver" ;
      public static final String DBURL = "jdbc:o racle:thin:@ localhost:1521:你的数据库的名字" ;
      public static final String DBUSER = "scott" ;
      public static final String DBPASSWORD = "tiger" ;
%>
<%
      Connection conn = null ;
      ;P reparedStatement pstmt = null ;
      ResultSet rs = null ;
%>
<%
      int currentPage = 1 ;       // 为当前所在的页，默认在第1页
      int lineSize = 3 ;             // 每次显示的记录数
      int allRecorders = 0 ;       // 表示全部的记录数
      int pageSize = 1 ;             // 表示全部的页数（尾页）
      int lsData[] = {1,3,5,7,9,10,15,20,25,30,50,100} ;
%>
<%
      try{
            currentPage = Integer.parseInt(request.getParameter("cp")) ;
      } catch(Exception e) {}
      try{
            lineSize = Integer.parseInt(request.getParameter("ls")) ;
      } catch(Exception e) {}
%>
<%
      Class.forName(DBDRIVER) ;
      conn = DriverManager.getConnection(DBURL,DBUSER,DBPASSWORD) ;
      String sql = "SELECT COUNT(empno) FROM emp" ;
      pstmt = conn.prepareStatement(sql) ;
      rs = pstmt.executeQuery() ;
      if(rs.next()){       // 取得全部的记录数
            allRecorders = rs.getInt(1) ;
      }
%>
<center>
      <h1>雇员列表</h1>
<script language="javascript">
      function go(num){
            document.getElementById("cp").value = num ;
            document.spform.submit() ;       // 表单提交
      }
</script>
<%
      pageSize = (allRecorders + lineSize -1) / lineSize ;
%>
<%
      sql =       "SELECT * FROM (       " +
                     " SELECT empno,ename,job,hiredate,sal,comm,ROWNUM rn " +
                     " FROM emp WHERE ROWNUM<=? ORDER BY empno) temp " +
                     " WHERE temp.rn>? " ;
      pstmt = conn.prepareStatement(sql) ;
      pstmt.setInt(1,currentPage * lineSize) ;
      pstmt.setInt(2,(currentPage-1) * lineSize) ;
      rs = pstmt.executeQuery() ;
%>
<form name="spform" action="<%=URL%>" method="post">
      <input type="button" value="首页" onclick="go(1)" <%=currentPage==1?"DISABLED":""%>>
      <input type="button" value="上一页" onclick="go(<%=currentPage-1%>)" <%=currentPage==1?"DISABLED":""%>>
      <input type="button" value="下一页" onclick="go(<%=currentPage+1%>)" <%=currentPage==pageSize?"DISABLED":""%>>
      <input type="button" value="尾页" onclick="go(<%=pageSize%>)" <%=currentPage==pageSize?"DISABLED":""%>>
      跳转到第<select name="selcp" onchange="go(this.value)">
            <%
                     for(int x=1;x<=pageSize;x++){
            %>
                              <option value="<%=x%>" <%=x==currentPage?"SELECTED":""%>><%=x%></option>
            <%
                     }
            %>
      </select>页
      每页显示
            <select name="ls" onchange="go(1)">
            <%
                     for(int x=0;x<lsData.length;x++){
            %>
                     <option value="<%=lsData[x]%>" <%=lsData[x]==lineSize?"SELECTED":""%>><%=lsData[x]%></option>
            <%
                     }
            %>
            </select>
      条
      <input type="hidden" name="cp" id="cp" value="1">
</form>
<TABLE BORDER="1" cellpadding="5" cellspacing="0" bgcolor="F2F2F2" width="100%">
      <TR onMouseOver="changeColor(this,'white')" onMouseOut="changeColor(this,'F2F2F2')">
            <td align="center" valign="middle"><span class="STYLE10">序号</span></td>
            <td align="center" valign="middle"><span class="STYLE10">编号</span></td>
            <td align="center" valign="middle"><span class="STYLE10">姓名</span></td>
            <td align="center" valign="middle"><span class="STYLE10">职位</span></td>
            <td align="center" valign="middle"><span class="STYLE10">雇佣日期</span></td>
            <td align="center" valign="middle"><span class="STYLE10">工资</span></td>
            <td align="center" valign="middle"><span class="STYLE10">奖金</span></td>
      </TR>
<%  int count = 0 ;
      while(rs.next()){

            int empno = rs.getInt(1) ;
            String ename = rs.getString(2) ;
            String job = rs.getString(3) ;
            Date hiredate = rs.getDate(4) ;
            double sal = rs.getDouble(5) ;
            double comm = rs.getDouble(6) ;
%>
      <TR onMouseOver="changeColor(this,'white')" onMouseOut="changeColor(this,'F2F2F2')">
            <td align="center" valign="middle"><span class="STYLE10"><%=++count%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=empno%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=ename%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=job%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=hiredate%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=sal%></span></td>
            <td align="center" valign="middle"><span class="STYLE6"><%=comm%></span></td>
      </TR>
<%
      }
%>
</table>
<%
      conn.close() ;
%>
</center>
</body>
</html>[/code]关键代码是[code=java]sql =    "SELECT * FROM ( " +
         " SELECT empno,ename,job,hiredate,sal,comm,ROWNUM rn " +
         " FROM emp WHERE ROWNUM<=? ORDER BY empno) temp " +
         " WHERE temp.rn>? " ;
pstmt = conn.prepareStatement(sql) ;
pstmt.setInt(1,currentPage * lineSize) ;
pstmt.setInt(2,(currentPage-1) * lineSize) ;
rs = pstmt.executeQuery() ;[/code]再补充一点，上面是直接发送sql查询语句的，也可以只发送参数，让数据库执行语句，可以编写存储过程（因为sql语句编译也要费时间，过程可以事先编译好）。
这是以oracle的emp表为例：

--先创建包package
create or replace package mypackage as
type v_cursor is ref cursor;
end mypackage;
--创建过程
create or replace procedure filterpage(
            tablename in varchar2 --表名
            pagesize in number --一页显示记录数
            currpage in number --当前页面
            totalcount out number --总记录数
            pagecount out number  --页数
            p_cursor out mypackage.v_cursor--结果集
         )
is

v_sql varchar2(100);
v_begin number:=(currpage-1)*pagesize + 1;
v_end number:=currpage*pagesize;

begin
v_sql:='select * from (select t1.*,rownum rn from '||tablename||'t1 where rownum <='||v_end||')where rn >='||v_begin;
open p_cursor for v_sql;
v_sql:='select count(*) from'||tablename;
execute immediate v_sql into totalcount;--立即执行并赋值
pagecount:=ceil(totalcount/pagesize); --向上取整（例如：5条记录，每页2条，就显示3页）

end;

给出一个调用的例子（核心部分）[code=java]//此处略去N个字符
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn = DriverManager.getConnection("jdbc:o racle:thin:@ 127.0.0.1:ORCL","scott","tiger");
CallableStatement cs = conn.prepareCall("{call filterpage(?,?,?,?,?,?)}");
cs.setString(1,"emp");
cs.setInt(2,10);//每页显10条记录
cs.setInt(3,2);//显示第二页
//参数注册
cs.registerOutParameter(4,oracle.jdbc.oracleTypes.INTEGER);
cs.registerOutParameter(5,oracle.jdbc.oracleTypes.INTEGER);
cs.registerOutParameter(6,oracle.jdbc.oracleTypes.CURSOR);
//执行
cs.execute();
int totalCount = cs.getInt(4);
int pageCount = cs.getInt(5);
ResultSet rs = (ResultSet)cs.getObject(6);
while(rs.next()){
//emp表的字段：EMPNO,ENAME,JOB,MGR HIREDATE,SAL,COMM,DEPTNO
int empno = rs.getInt(1) ;
String ename = rs.getString(2) ;
String job = rs.getString(3) ;
Date hiredate = rs.getDate(5) ;
double sal = rs.getDouble(6) ;
double comm = rs.getDouble(7) ;
｝
//此处略去N个字符[/code]我以前花了不少时间找到这些资料，现在整理出来，都是可运行的。
当然这些都是入门级的，以后肯定不是这些，但是作为学习，是必须要经历的（将java代码卸载jsp页面中）。
[ 本帖最后由王亮于 2011-07-23  14:00 编辑 ]

发表于 2011-7-21 22:58:24

看了第一眼就想哭

admin · 发表于 2011-7-21 22:02:57

首先澄清下，下面的代码不是我写的，你可以借鉴，我曾经做个一次，但是源码找不到了，这个我读了，觉着可行，但愿对你有帮助
package comman;

import java.util.ArrayList;

public  class Page implements java.io.Serializable {

private int curPage = 1; //当前是第几页
private int maxPage = 1; //一共有多少页
private int maxRowCount ; //一共有多少行
private int rowsPerPage = 5 ;//每页多少行
private int curRow; //当前行

public Page(int maxRowCount){
  this.maxRowCount = maxRowCount;
  init();
}

public void init()
{
  if (this.getMaxRowCount()==0){
this.setCurPage(1);
this.setMaxPage(1);
  }
  if (this.getMaxRowCount()% this.getRowsPerPage()==0){
this.maxPage = this.maxRowCount/this.rowsPerPage;
  }else{
this.maxPage = this.maxRowCount/this.rowsPerPage + 1;
  }
  System.out.println("maxPage:" + maxPage);
  this.setCurRow();
}

public int getCurPage() {
  return curPage;
}

public void setCurPage(int curPage) {
  this.curPage = curPage;
}

public int getMaxPage() {
  return maxPage;
}

public void setMaxPage(int maxPage) {
  this.maxPage = maxPage;
}

public int getMaxRowCount() {
  return maxRowCount;
}

public void setMaxRowCount(int maxRowCount) {
  this.maxRowCount = maxRowCount;
}

public int getRowsPerPage() {
  return rowsPerPage;
}

public void setRowsPerPage(int rowsPerPage) {
  this.rowsPerPage = rowsPerPage;
}

public int getCurRow() {
  return curRow;
}

public void setCurRow() {
  this.curRow = (curPage - 1) * rowsPerPage ;
}

}

然后再建立关于数据库连接以及查询的DAO文件,代码如下:

package com.ibm.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import comman.Page;
import com.struts.form.*;

public class UsersDAO
{
private static UsersDAO udao =null;

public static UsersDAO getInstance()
{
  if(udao!=null)
  {
return udao;
  }else
  {
udao = new UsersDAO();
return udao;
  }
}

private PreparedStatement ps;
private ResultSet rs;
private int c;
private AddMemberForm addMemberForm;

public int getAllRows(Connection con)
{
  String sql = "select count(*) from memberinfo";
  try {
ps = con.prepareStatement(sql);
rs = ps.executeQuery();
rs.next();
c = rs.getInt(1);

  } catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
  }
  return c;
}

public ArrayList getAllUsers(Connection con,Page page)
{
  ArrayList list = new ArrayList();
  String sql = "select * from memberinfo order by id desc limit ?,?";
  AddMemberForm addMemberForm =null;
  try {
ps = con.prepareStatement(sql);
ps.setInt(1, page.getCurRow());
ps.setInt(2, page.getRowsPerPage());
rs = ps.executeQuery();
while(rs.next())
{
addMemberForm = new AddMemberForm();
addMemberForm.setAddress(rs.getString("address"));
addMemberForm.setEmail(rs.getString("email"));
int d=rs.getInt("id");
String d1=Integer.toString(d);
addMemberForm.setId(d1);
addMemberForm.setName(rs.getString("name"));
addMemberForm.setPhone(rs.getString("phone"));
list.add(addMemberForm);
}
  } catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
  }
  return list;
}

}
关于实例初始化的service包文件:

package service;

import java.sql.Connection;
import java.util.ArrayList;

import comman.Page;
import com.ibm.dao.UsersDAO;

public class UsersBIZ {
private static UsersBIZ ubiz =null;

public static UsersBIZ getInstance()
{
  if(ubiz!=null)
  {
return ubiz;
  }else
  {
ubiz = new UsersBIZ();
return ubiz;
  }
}

public int getAllRows(Connection con)
{
  return UsersDAO.getInstance().getAllRows(con);
}

public ArrayList queryAllUsers(Connection con, Page page)
{
  return UsersDAO.getInstance().getAllUsers(con, page);
}
}
这样,基本的几个类文件就写好了.

接下来就是要在Jsp页面中添加代码了(这里只列出了部分关键代码):

<form name="PageForm" action="memberDetails.do" method="post">
         每页
         <%=pageCtrl.getRowsPerPage()%>
         行共
         <%=pageCtrl.getMaxRowCount()%>
         行第
         <%=pageCtrl.getCurPage()%>
         页共
         <%=pageCtrl.getMaxPage()%>
         页
         <BR>
         <%
         if (pageCtrl.getCurPage() == 1) {
         out.print(" 首页上一页");
         } else {
         %>
         <A HREF="javascript:gotoPage(1)">首页</A>
         <A HREF="javascript:gotoPage(<%=pageCtrl.getCurPage() - 1%>)">上一页</A>
         <%
         }
         %>
         <%
         if (pageCtrl.getCurPage() == pageCtrl.getMaxPage()) {
         out.print("下一页尾页");
         } else {
         %>
         <A HREF="javascript:gotoPage(<%=pageCtrl.getCurPage() + 1%>)">下一页</A>
         <A HREF="javascript:gotoPage(<%=pageCtrl.getMaxPage()%>)">尾页</A>
         <%
         }
         %>
         转到第
         <SELECT name="jumpPage" onchange="Jumping()">
         <%
            for (int i = 1; i <= pageCtrl.getMaxPage(); i++) {
            if (i == pageCtrl.getCurPage()) {
         %>
         <OPTION selected value=<%=i%>>
         第<%=i%>页
         </OPTION>
         <%
         } else {
         %>
         <OPTION value=<%=i%>>
         第<%=i%>页
         </OPTION>
         <%
         }
         }
         %>
         </SELECT>
         页

      </form>

最后,比较重要的就是在Action文件下session,以便于在jsp页面中调用(部分关键代码).

private HttpSession session;
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
  ProcessBean pb=new ProcessBean();
      Connection con =pb.con;
  session = request.getSession();
  int maxRows = UsersBIZ.getInstance().getAllRows(con);

  Page page = new Page(maxRows);
  String pageNo = request.getParameter("jumpPage");
  if(!"".equals(pageNo) && null != pageNo ){
page.setCurPage(Integer.parseInt(pageNo));
  }
  page.init();
  System.out.println(page.getCurPage());
  System.out.println(page.getCurRow());
  System.out.println(page.getMaxPage());
  System.out.println(page.getMaxRowCount());
  System.out.println(page.getRowsPerPage());

  ArrayList list = UsersBIZ.getInstance().queryAllUsers(con, page);


  session.setAttribute("list", list);
  session.setAttribute("page", page);

  return mapping.findForward("success");

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