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servlet分页代码示例

发布时间：2023-01-01 05:01:23 来源：互联网

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人生在世，想美好的事情，就会找到快乐，走向成功；想失意的事情，就会走向失望的深渊，无力面对生活和失败。

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" rel="nofollow noopener noreferrer" 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 rel="nofollow noopener noreferrer" href="Servlet?page=1">首页</a>
 <a rel="nofollow noopener noreferrer" href="Servlet?page=<%=curPage - 1%>">上一页</a>
 <%
 }else {
 %>
 首页 上一页
 <%
 }%>
 <%if (curPage < maxPage){
 %>
 <a rel="nofollow noopener noreferrer" href="Servlet?page=<%=curPage + 1%>">下一页</a>
 <a rel="nofollow noopener noreferrer" 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>