servlet分页代码示例

1.首先创建一个对象 userdata，用以保存从数据库中获取的数据。

package com.tool;

import java.math.bigdecimal;
import java.util.date;

/**
 * created by lx_sunwei on 14-1-6.
 */
public class userdata {

    /**
     * emp表中的数据属性
     */
    private string ename;
    private string job;
    private bigdecimal empno;
    private bigdecimal mgr;
    private date hiredate;
    private bigdecimal sal;
    private bigdecimal comm;
    private bigdecimal deptno;

    public bigdecimal getempno() {
        return empno;
    }

    public void setempno(bigdecimal empno) {
        this.empno = empno;
    }

    public bigdecimal getmgr() {
        return mgr;
    }

    public void setmgr(bigdecimal mgr) {
        this.mgr = mgr;
    }

    public date gethiredate() {
        return hiredate;
    }

    public void sethiredate(date hiredate) {
        this.hiredate = hiredate;
    }

    public bigdecimal getsal() {
        return sal;
    }

    public void setsal(bigdecimal sal) {
        this.sal = sal;
    }

    public bigdecimal getcomm() {
        return comm;
    }

    public void setcomm(bigdecimal comm) {
        this.comm = comm;
    }

    public bigdecimal getdeptno() {
        return deptno;
    }

    public void setdeptno(bigdecimal deptno) {
        this.deptno = deptno;
    }

    public string getename() {
        return ename;
    }

    public void setename(string ename) {
        this.ename = ename;
    }

    public string getjob() {
        return job;
    }

    public void setjob(string job) {
        this.job = job;
    }
}

2.创建一个 dbhelper 对象用以与数据库进行交互

package com.dao;

import com.tool.userdata;

import java.math.bigdecimal;
import java.sql.*;
import java.util.*;
import java.util.date;

/**
 * created by lx_sunwei on 14-1-6.
 */
public class dbhelper {

    connection conn;  //数据库连接对象
    preparedstatement pt;  //sql语句预处理对象
    resultset rs;  //结果集对象

    public  dbhelper(){
        try {
            class.forname("oracle.jdbc.driver.oracledriver");  //装载驱动
        } catch (classnotfoundexception e) {
            e.printstacktrace();
        }
    }

    /**
     * 获取当前页的数据
     * @param curpage
     * @param rowsperpage
     * @return
     */
    public list<userdata> getdata(int curpage, int rowsperpage) {

        list<userdata> datalist = new arraylist<>();
        string url = "jdbc:oracle:thin:@localhost:1521:orcl";
        try {
            conn = drivermanager.getconnection(url,"scott","tiger");
            string sql = "select * from emp where rownum <= ((? - 1) * "+rowsperpage+" + "+rowsperpage+") minus " +
                    " select * from emp where rownum <= (? - 1) * "+rowsperpage+" ";
            pt = conn.preparestatement(sql);
            pt.setint(1,curpage);
            pt.setint(2,curpage);
            rs = pt.executequery();
            while (rs.next()){
                /**
                 * 从结果集中取得数据
                 */
                userdata userdata = new userdata();
                bigdecimal empno = rs.getbigdecimal("empno");
                string ename = rs.getstring("ename");
                string job = rs.getstring("job");
                bigdecimal mgr = rs.getbigdecimal("mgr");
                date hiredate = rs.getdate("hiredate");
                bigdecimal sal = rs.getbigdecimal("sal");
                bigdecimal comm = rs.getbigdecimal("comm");
                bigdecimal deptno = rs.getbigdecimal("deptno");
                /**
                 * 设置对象属性
                 */
                userdata.setempno(empno);
                userdata.setename(ename);
                userdata.setjob(job);
                userdata.setmgr(mgr);
                userdata.sethiredate(hiredate);
                userdata.setsal(sal);
                userdata.setcomm(comm);
                userdata.setdeptno(deptno);
                datalist.add(userdata);  //把对象添加集合中
            }
            rs.close();
            pt.close();
            conn.close();
        } catch (sqlexception e) {
            e.printstacktrace();
        }
        return datalist;
    }

    /**
     * 返回总页数
     * @return
     */
    public int getmaxpage(int rowsperpage) {
        int maxpage;
        int maxrowcount = 0;
        string url = "jdbc:oracle:thin:@localhost:1521:orcl";
        try {
            conn = drivermanager.getconnection(url,"scott","tiger");  //创建数据库连接
            string sql = "select count(*) from emp";
            pt = conn.preparestatement(sql);
            rs = pt.executequery();
            if (rs.next()){
                maxrowcount = rs.getint(1);  //总行数
            }
        } catch (sqlexception e) {
            e.printstacktrace();
        }
        maxpage = (maxrowcount + rowsperpage - 1) / rowsperpage;  //总页数
        return maxpage;
    }
}

3.创建 servlet 对显示页面进行控制

package com.servlet;

import com.dao.dbhelper;
import com.tool.userdata;

import javax.servlet.requestdispatcher;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import java.io.ioexception;
import java.util.*;

/**
 * created by lx_sunwei on 14-1-6.
 */
public class servlet extends httpservlet {

    public int rowsperpage;  //每页显示的行数
    public int curpage;  //当前页页码
    public int maxpage;  //总共页数
    dbhelper db = new dbhelper();
    public servlet(){
        rowsperpage = 5;
    }

    protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
        string curpage1 = request.getparameter("page");  //获取当前页页码
        if (curpage1 == null){
            curpage = 1;
            request.setattribute("curpage",curpage);  //设置curpage对象
        }else {
            curpage = integer.parseint(curpage1);
            if (curpage < 1){
                curpage = 1;
            }
            request.setattribute("curpage",curpage);
        }

        list<userdata> datalist;
        datalist = db.getdata(curpage,rowsperpage);  //获取当前页的数据
        maxpage = db.getmaxpage(rowsperpage);  //获取总页数
        request.setattribute("datalist",datalist);
        request.setattribute("maxpage", maxpage);

        requestdispatcher rd = request.getrequestdispatcher("pagemain.jsp");  //将请求转发到pagemain.jsp页面
        rd.forward(request,response);
    }

    protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
        dopost(request,response);
    }
}

4.创建 jsp 页面，显示数据。

<%@ page import="java.util.list" %>
<%@ page import="com.tool.userdata" %>
<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
<head>
    <title>servlet数据分页</title>
    <link rel="stylesheet" type="text/css" href="css.css">
</head>
<body>
<div style="margin-top: 15%; margin-left: 25%">
    <table>
        <caption>scott用户，emp表中的数据</caption>
        <%! int curpage,maxpage; %>
        <% curpage =integer.parseint(request.getattribute("curpage").tostring()); %> <!--取得当前页-->
        <% maxpage =integer.parseint((string)request.getattribute("maxpage").tostring()); %> <!--取得总页数-->
        <%if (request.getattribute("datalist") == null){
        %>
        <tr>
            <td colspan="8">没有数据</td>
        </tr>
        <%
        }else {
        %>
        <tr>
            <!--表头-->
            <th>empno</th>
            <th>ename</th>
            <th>job</th>
            <th>mgr</th>
            <th>hiredate</th>
            <th>sal</th>
            <th>comm</th>
            <th>deptno</th>
        </tr>
        <%
            list list = (list) request.getattribute("datalist");
            for (object alist : list) {
                userdata userdata = (userdata) alist;
        %>
        <tr>
            <!--取得表中数据-->
            <td><%= userdata.getempno() %></td>
            <td><%= userdata.getename() %></td>
            <td><%= userdata.getjob() %></td>
            <td><%= userdata.getmgr() %></td>
            <td><%= userdata.gethiredate() %></td>
            <td><%= userdata.getsal() %></td>
            <td><%= userdata.getcomm() %></td>
            <td><%= userdata.getdeptno() %></td>
        </tr>
        <%
                }
            }
        %>
    </table>
</div>
<div style="margin-top: 8%; margin-left: 29%">
    第<%= curpage %>页，共<%= maxpage %>页  
    <%if (curpage > 1){
    %>
    <a href="servlet?page=1">首页</a>
    <a href="servlet?page=<%=curpage - 1%>">上一页</a>
    <%
    }else {
    %>
    首页 上一页
    <%
        }%>
    <%if (curpage < maxpage){
    %>  
    <a href="servlet?page=<%=curpage + 1%>">下一页</a>
    <a href="servlet?page=<%=maxpage %>">尾页</a>
    <%
    }else {
    %>
    下一页 尾页
    <%
        }%>
      转至第 <form name="form1" action="servlet" method="get">
    <label>
        <select name="page" onchange="document.form1.submit()">
            <%for ( int i = 1; i <= maxpage; i++){
                if (i == curpage){
            %>
            <!--当前页页码默认选中-->
            <option selected value="<%= i%>"><%= i %></option>
            <%
            }else {
            %>
            <option value="<%= i %>"><%= i %></option>
            <%
                    }
                }%>
        </select>
    </label>
</form> 页
</div>
</body>
</html>

web.xml 中的配置文件为：

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
           xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
           xsi:schemalocation="http://java.sun.com/xml/ns/javaee
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
           version="3.0">

    <servlet>
        <servlet-name>servlet</servlet-name>
        <servlet-class>com.servlet.servlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>servlet</servlet-name>
        <url-pattern>/servlet</url-pattern>
    </servlet-mapping>

</web-app>

把项目部署到 tomcat 服务器上，输入地址：http://localhost:8080/servlet   这样就可以看到效果