最近在做毕设，需要写一个管理系统，对几个框架也不很是很熟练，所以就打算servlet和jsp来做这个项目。
其中分页是比较麻烦的一个问题，就在慕课网上找了视频看，整理了实现步骤。大家可以直接看我博客，
也可以直接去看视频。此处附上原视频链接：https://www.imooc.com/learn/180
话不多说，先直接上效果图，有兴趣的话再往下看：
准备撸代码了：
一、准备工作
开发工具：myeclipse
数据库：mysql
二、创建数据库相关文件
先创建一个数据库pagination，然后创建t_student表，此处贴上sql脚本：
DROP TABLE IF EXISTS `t_student`;
CREATE TABLE `t_student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`stu_name` varchar(16) NOT NULL,
`gender` int(11) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`address` varchar(128) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8;
INSERT INTO `t_student` VALUES ('1', '王小军', '1', '17', '北京市东城区');
INSERT INTO `t_student` VALUES ('2', '李雷雷', '1', '16', '北京市朝阳区');
INSERT INTO `t_student` VALUES ('3', '张静', '2', '16', '北京市昌平区');
INSERT INTO `t_student` VALUES ('4', '王晓萌', '2', '17', '北京市顺义区');
INSERT INTO `t_student` VALUES ('5', '韩梅梅', '2', '16', '北京市朝阳区');
INSERT INTO `t_student` VALUES ('6', '李小军', '1', '17', '北京市海淀区');
INSERT INTO `t_student` VALUES ('7', '成龙', '1', '16', '北京市石景山区');
INSERT INTO `t_student` VALUES ('8', '李海飞', '2', '16', '北京市海淀区');
INSERT INTO `t_student` VALUES ('9', '罗红', '2', '16', '北京市朝阳区');
INSERT INTO `t_student` VALUES ('10', '孙海杰', '1', '16', '北京市石景山区');
INSERT INTO `t_student` VALUES ('11', '王海龙', '1', '16', '北京市东城区');
三、开始正题了，创建java web项目
1.首先创建以下目录，下面再一一讲解每个目录中文件
2.在model包下创建Student类、Pager类和Contants类：
Student就不用解释了（注意其中有个根据参数为map对象的构造函数），
Pager是jsp页面需要展示的对象，包括pageSize、pageNum、totalRecord、totalPage、studentList
这些在jsp页面需要的属性
Contants中定义了一些常量
package com.wang.PaginationTest.model;
import java.io.Serializable;
import java.util.Map;
public class Student implements Serializable{
private static final long serialVersionUID = -2673637313342809713L;
private int id;
private String stuName;
private int age;
private int gender;
private String address;
public Student() {
super();
}
//注意此处有个以map为参数的构造函数
public Student(Map<String, Object> map) {
this.id = (Integer)map.get("id");
this.stuName = (String)map.get("stu_name");
this.age = (Integer)map.get("age");
this.gender = (Integer)map.get("gender");
this.address = (String)map.get("address");
}
public Student(int id, String stuName, int age, int gender, String address) {
super();
this.id = id;
this.stuName = stuName;
this.age = age;
this.gender = gender;
this.address = address;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getStuName() {
return stuName;
}
public void setStuName(String stuName) {
this.stuName = stuName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getGender() {
return gender;
}
public void setGender(int gender) {
this.gender = gender;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
@Override
public String toString() {
return "Student [id=" + id + ", stuName=" + stuName + ", age=" + age
+ ", gender=" + gender + ", address=" + address + "]";
}
}
package com.wang.PaginationTest.model;
import java.io.Serializable;
import java.util.List;
/**
* @author Mr.Wang
*
* @param <T>
*/
public class Pager<T> implements Serializable{
private static final long serialVersionUID = 1272640772922982817L;
private int pageSize;
private int currentPage;
private int totalRecord;
private int totalPage;
private List<T> dataList;
public Pager() {
super();
}
public Pager(int pageSize, int currentPage, int totalRecord, int totalPage,
List<T> dataList) {
super();
this.pageSize = pageSize;
this.currentPage = currentPage;
this.totalRecord = totalRecord;
this.totalPage = totalPage;
this.dataList = dataList;
}
public Pager(int pNum,int pSize,List<T> sourceData){
if(sourceData==null)
return;
totalRecord = sourceData.size();
pageSize = pSize;
currentPage = pNum;
totalPage = (totalRecord%pageSize)==0?(totalRecord/pageSize):(totalRecord/pageSize+1);
int fromIndex = (currentPage-1)*pageSize;
int toIndex = (currentPage*pageSize<=totalRecord)?(currentPage*pageSize):totalRecord;
dataList = sourceData.subList(fromIndex, toIndex);
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalRecord() {
return totalRecord;
}
public void setTotalRecord(int totalRecord) {
this.totalRecord = totalRecord;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public List<T> getDataList() {
return dataList;
}
public void setDatalist(List<T> dataList) {
this.dataList = dataList;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
}
package com.wang.PaginationTest.model;
public class Constants {
public static final int GENDER_MALE=1; //男性
public static final int GENDER_FEMALE=2; //女性
public static final int DEFAULT_GENDER=0; //男女
public static final int DEFAULT_PAGENUM=1; //默认当前页
public static final int DEFAULT_PAGESIZE=5; //默认页面大小为5
}
3.jdbc连接：
jdbc.properties的内容如下：（注意改为自己数据库的用户名和密码）
jdbc.username=root
jdbc.password=123456
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/paginationpackage com.wang.pagination.util;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
public class JdbcUtil {
private static String USERNAME;
private static String PASSWORD;
private static String DRIVER;
private static String URL;
private Connection connection;
private PreparedStatement pstmt;
private ResultSet resultSet;
static{
loadConfig();
}
/**
* 加载配置文件jdbc.propertiesֵ
*/
public static void loadConfig(){
try {
InputStream inStream = JdbcUtil.class
.getResourceAsStream("/jdbc.properties");
Properties prop = new Properties();
prop.load(inStream);
USERNAME = prop.getProperty("jdbc.username");
PASSWORD = prop.getProperty("jdbc.password");
DRIVER = prop.getProperty("jdbc.driver");
URL = prop.getProperty("jdbc.url");
} catch (Exception e) {
throw new RuntimeException("加载配置文件异常", e);
}
}
public JdbcUtil() {
}
//创建Connection
public Connection getConnection() {
try {
Class.forName(DRIVER);
connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
} catch (Exception e) {
throw new RuntimeException("get connection error!");
}
return connection;
}
/**
*更新语句
*params为查询条件参数list
*/
public boolean updateByPreparedStatement(String sql, List<?> params)
throws SQLException {
boolean flag = false;
int result = -1;
pstmt = connection.prepareStatement(sql);
int index = 1;
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
pstmt.setObject(index++, params.get(i));
}
}
result = pstmt.executeUpdate();
flag = result > 0 ? true : false;
return flag;
}
/**
*查询语句
*每个map以键（属性）值对的形式存储一个对象
*list存储这样的多个map
*/
public List<Map<String, Object>> findResult(String sql, List<?> params)
throws SQLException {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
int index = 1;
pstmt = connection.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
pstmt.setObject(index++, params.get(i));
}
}
resultSet = pstmt.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int cols_len = metaData.getColumnCount();
while (resultSet.next()) {
Map<String, Object> map = new HashMap<String, Object>();
for (int i = 0; i < cols_len; i++) {
String cols_name = metaData.getColumnName(i + 1);
Object cols_value = resultSet.getObject(cols_name);
if (cols_value == null) {
cols_value = "";
}
map.put(cols_name, cols_value);
}
list.add(map);
}
return list;
}
/**
* 释放资源
*/
public void releaseConn() {
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
} 4.在dao包和service包下分别创建StudentDao和StudentService接口类
package com.wang.PaginationTest.dao;
import com.wang.PaginationTest.model.Pager;
import com.wang.PaginationTest.model.Student;
public interface StudentDao {
public Pager<Student> findStudent(Student model,int pageNum,int pageSize);
}
package com.wang.PaginationTest.service;
import com.wang.PaginationTest.model.Pager;
import com.wang.PaginationTest.model.Student;
public interface StudentService {
public Pager<Student> findStudent(Student model,int pageNum,int pageSize);
}
5. 在dao包和service包下分别创建 StudentDaoImpl.java和 StudentServiceImpl.java
package com.wang.PaginationTest.dao;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.wang.PaginationTest.model.Constants;
import com.wang.PaginationTest.model.Pager;
import com.wang.PaginationTest.model.Student;
import com.wang.PaginationTest.util.JdbcUtil;
public class StudentDaoImpl implements StudentDao{
@Override
public Pager<Student> findStudent(Student model, int pageNum, int pageSize) {
Pager<Student> result=null;
List<Object> paramList = new ArrayList<Object>(); //查询参数list
String stuName = model.getStuName(); //两个查询参数
int gender = model.getGender();
StringBuilder sql = new StringBuilder("select * from t_student where 1=1 ");
StringBuilder countSql = new StringBuilder("select count(id) as recordTotal from t_student where 1=1 ");
if(stuName!=null&&!stuName.equals("")){
sql.append("and stu_name like ? ");
countSql.append("and stu_name like ? ");
paramList.add("%"+stuName+"%");
}
if(gender==Constants.GENDER_MALE||gender==Constants.GENDER_FEMALE){
sql.append("and gender = ? " );
countSql.append("and gender = ? ");
paramList.add(gender);
}
int fromIndex = (pageNum-1)*pageSize;
sql.append(" limit "+ fromIndex +","+ pageSize);
JdbcUtil jdbcUtil = null;
try {
jdbcUtil = new JdbcUtil();
jdbcUtil.getConnection();
//取总记录数
List<Map<String, Object>> totalList = jdbcUtil.findResult(countSql.toString(), paramList);
Map<String, Object> totalMap = totalList.get(0);
int recordTotal = ((Number)totalMap.get("recordTotal")).intValue();
//取stuList
List<Student> stuList = new ArrayList<Student>();
List<Map<String, Object>> findStuResult = jdbcUtil.findResult(sql.toString(), paramList);
for (Map<String, Object> map : findStuResult) {
Student stu = new Student(map);
stuList.add(stu);
}
int totalPage = recordTotal/pageSize;
if(recordTotal%pageSize!=0){
totalPage+=1;
}
result =new Pager<Student>(pageSize, pageNum, recordTotal, totalPage, stuList);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(jdbcUtil!=null)
jdbcUtil.releaseConn();
}
return result;
}
}
package com.wang.PaginationTest.service;
import com.wang.PaginationTest.dao.StudentDao;
import com.wang.PaginationTest.dao.StudentDaoImpl;
import com.wang.PaginationTest.model.Pager;
import com.wang.PaginationTest.model.Student;
public class StudentServiceImpl implements StudentService{
StudentDao stuDao;
public StudentServiceImpl(){
stuDao = new StudentDaoImpl();
}
@Override
public Pager<Student> findStudent(Student model, int pageNum, int pageSize) {
// TODO Auto-generated method stub
Pager<Student> pager = stuDao.findStudent(model, pageNum, pageSize);
return pager;
}
}
6.在servlet包下创建StudentServlet.java
package com.wang.PaginationTest.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.wang.PaginationTest.model.Constants;
import com.wang.PaginationTest.model.Pager;
import com.wang.PaginationTest.model.Student;
import com.wang.PaginationTest.service.StudentServiceImpl;
import com.wang.PaginationTest.service.StudentService;
public class StudentServlet extends HttpServlet {
private static final long serialVersionUID = -99919030529746195L;
private StudentService stuService = new StudentServiceImpl();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=utf-8");
//获取request参数
String stuName = request.getParameter("stuName");
int gender = Constants.DEFAULT_GENDER;
String genderStr = request.getParameter("gender");
if(genderStr!=null&& !"".equals(genderStr)){
gender = Integer.parseInt(genderStr);
}
int pageSize = Constants.DEFAULT_PAGESIZE;
String pageSizeStr = request.getParameter("pageSize");
if(pageSizeStr!=null&& !"".equals(pageSizeStr)){
pageSize = Integer.parseInt(pageSizeStr);
}
int pageNum = Constants.DEFAULT_PAGENUM;
String pageNumStr = request.getParameter("pageNum");
if(pageNumStr!=null&& !"".equals(pageNumStr)){
pageNum = Integer.parseInt(pageNumStr);
}
//组装查询条件
Student stu = new Student();
stu.setStuName(stuName);
stu.setGender(gender);
//调用service查询
Pager<Student> result = stuService.findStudent(stu, pageNum, pageSize);
//返回结果
request.setAttribute("result", result);
request.getRequestDispatcher("pagination.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
7.pagination.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学生信息</title>
</head>
<%
// 获取请求的上下文
String context = request.getContextPath();
%>
<script type="text/javascript">
// 当前第几页数据
var currentPage = ${result.currentPage};
// 总页数
var totalPage = ${result.totalPage};
function submitForm(actionUrl){
var formElement = document.getElementById("stuForm");
formElement.action = actionUrl;
formElement.submit();
}
// 第一页
function firstPage(){
if(currentPage == 1){
alert("已经是第一页数据");
return false;
}else{
submitForm("<%=context %>/StudentServlet?pageNum=1");
return true;
}
}
// 下一页
function nextPage(){
if(currentPage == totalPage){
alert("已经是最后一页数据");
return false;
}else{
submitForm("<%=context %>/StudentServlet?pageNum=" + (currentPage+1));
return true;
}
}
// 上一页
function previousPage(){
if(currentPage == 1){
alert("已经是第一页数据");
return false;
}else{
submitForm("<%=context %>/StudentServlet?pageNum=" + (currentPage-1));
return true;
}
}
// 尾页
function lastPage(){
if(currentPage == totalPage){
alert("已经是最后一页数据");
return false;
}else{
submitForm("<%=context %>/StudentServlet?pageNum=${result.totalPage}");
return true;
}
}
function initPage(){
var genderRequest = "${gender}" ;
var genderVal = 0;
var genderElement = document.getElementById("gender");
if(genderRequest != ""){
genderVal = parseInt(genderRequest);
}
var options = genderElement.options;
var i = 0;
for(i = 0; i < options.length; i++){
if(options[i].value == genderVal){
options[i].selected=true;
break;
}
}
}
</script>
<body onload="initPage();">
<div style="margin-left: 100px; margin-top: 100px;">
<div>
<font color="red">${errorMsg }</font>
</div>
<div>
<form action="<%=context %>/StudentServlet" id="stuForm" method="post">
姓名
<input type="text" name="stuName" id="stu_name" style="width:120px" value="${stuName }">
性别
<select name="gender" id="gender" style="width:80px">
<option value="0">全部</option>
<option value="1">男</option>
<option value="2">女</option>
</select>
<input type="submit" value="查询">
</form>
</div>
<br>
学生信息列表：<br>
<br>
<!-- 后台返回结果为空 -->
<c:if test="${fn:length(result.dataList) eq 0 }">
<span>查询的结果不存在</span>
</c:if>
<!-- 后台返回结果不为空 -->
<c:if test="${fn:length(result.dataList) gt 0 }">
<table border="1px" cellspacing="0px"
style="border-collapse: collapse">
<thead>
<tr height="30">
<th width="130">姓名</th>
<th width="130">性别</th>
<th width="130">年龄</th>
<th width="190">家庭地址</th>
</tr>
</thead>
<c:forEach items="${result.dataList }" var="student">
<tr>
<td><c:out value="${student.stuName }"></c:out></td>
<td>
<c:if test="${ student.gender eq 1}">男</c:if>
<c:if test="${ student.gender eq 2}">女</c:if>
</td>
<td><c:out value="${student.age }"></c:out></td>
<td><c:out value="${student.address }"></c:out></td>
</tr>
</c:forEach>
</table>
<br> 共${result.totalRecord }条记录共${result.totalPage }页 当前第${result.currentPage }页
<a href="#" onclick="firstPage();">首页</a>
<a href="#" onclick="nextPage();">下一页</a>
<a href="#" onclick="previousPage();">上一页</a>
<a href="#" onblur="lastPage();">尾页</a>
</c:if>
</div>
</body>
</html><?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
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">
<servlet>
<servlet-name>StudentServlet</servlet-name>
<servlet-class>com.wang.PaginationTest.servlet.StudentServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>StudentServlet</servlet-name>
<url-pattern>/StudentServlet</url-pattern>
</servlet-mapping>
</web-app>