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。

  

复制代码 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

  

复制代码 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

  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

  

复制代码 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。

  

复制代码 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:

  

复制代码 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