本文介绍了servlet分页代码实现，采用Oracle数据库，获取SCOTT用户EMP表中的数据，分页实现步骤看下面代码
1.首先创建一个对象 UserData，用以保存从数据库中获取的数据。
代码如下:
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
代码如下:
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
publicDBHelper(){
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
代码如下:
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。
代码如下:
<%@ 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：
代码如下:
<?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
