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
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