第83节:Java中的学生管理系统分页功能
第83节:Java中的学生管理系统分页功能
分页功能一般可以做成两种，一种是物理分页，另一种是逻辑分页。这两种功能是有各自的特点的，物理分页是查询的时候，对数据库进行访问，只是查一页数据就进行返回，其特点是对内存中数据量存储不大，只是缺点就是要对数据库不断的进行访问；而对逻辑分页来说，就有所不同，它是一下子就把所有的数据全部查询出来，然后放入到内存中，访问速度快，缺点就是对内存空间不足，数据量过大。
select * from stu limit 5;
效果
// offset 偏移前面的多少条，offset 1 跳过前面的一条
select * from stu limit 5 offset 5;
效果
SELECT * FROM stu LIMIT 5 , 5;
效果
SELECT * FROM stu LIMIT 5 , 2;SELECT * FROM stu LIMIT 2 , 5;
效果
写分页的dao模式
// index.jsp
<h3><a href="StudentListPageServlet?currentPage=1">分页显示所有学生</a></h3>// StudentListPageServlet
//1. 获取需要显示的页码数
int currentPage =Integer.parseInt( request.getParameter("currentPage"));// StudentDao
// 接口中定义的成员都是常量
// 一页显示多少条记录
int PAGE_SIZE = 5;
// 分页dao,查询当页的学生数据
List<Student> findStudentByPage(int currentPage) throws SQLException;
效果
// StudentDaoImpl
@Override
public List<Student> findStudentByPage(int currentPage) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
// 第一个问号，一页返回多少条记录，第二个问号，跳过前面的多少条记录
//5 0 --- 第一页 (1-1)*5
//5 5 --- 第二页 (2-1)*5
//5 10 --- 第三页
return runner.query("select * from stu limit ? offset ?", new BeanListHandler<Student>(Student.class),PAGE_SIZE , (currentPage-1)*PAGE_SIZE);
}业务逻辑
select count(*) from stu;
效果
业务逻辑
package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.PageBean;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* 这是用于分页显示学生列表的servlet
*/
public class StudentListPageServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
//1. 获取需要显示的页码数
int currentPage =Integer.parseInt( request.getParameter("currentPage"));
//2. 根据指定的页数，去获取该页的数据回来
//List<Student> --- list.jsp
StudentService service = new StudentServiceImpl();
PageBean pageBean= service.findStudentByPage(currentPage);
request.setAttribute("pageBean", pageBean);
//3. 跳转界面。
request.getRequestDispatcher("list_page.jsp").forward(request, response);
} catch (SQLException e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}去业务逻辑去找
package com.dashucoding.service;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.domain.PageBean;
import com.dashucoding.domain.Student;
/*
* 这是学生的业务处理规范
* */
public interface StudentService {
// 分页dao,查询当页的学生数据
// 分页的很多小逻辑业务 可以做到service里面
// 业务做到service里面，做的就是bean了，当前页，总页数，显示条数， 总记录数
// 返回的是一个bean了
// 返回的是PageBean里面的所有数据了
PageBean findStudentByPage(int currentPage) throws SQLException;
// 根据姓名或性别，查询
List<Student> searchStudent(String sname, String sgender) throws SQLException;
/*
* 查询所有学生 list<Student>
*/
List<Student> findAll() throws SQLException;
void insert(Student student) throws SQLException;
// sid根据id删除学生
void delete(int sid) throws SQLException;
// 根据id查询单个学生对象
Student findStudentById(int sid) throws SQLException;
// 更新学生信息
void update(Student student) throws SQLException;
}package com.dashucoding.service.impl;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.dao.StudentDao;
import com.dashucoding.dao.impl.StudentDaoImpl;
import com.dashucoding.domain.PageBean;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
/*
* 这是学生业务实现
* */
public class StudentServiceImpl implements StudentService {
@Override
public List<Student> findAll() throws SQLException {
StudentDao dao = new StudentDaoImpl();
return dao.findAll();
}
@Override
public void insert(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.insert(student);
}
@Override
public void delete(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.delete(sid);
}
@Override
public Student findStudentById(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.findStudentById(sid);
}
@Override
public void update(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.update(student);
}
@Override
public List<Student> searchStudent(String sname, String sgender) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.searchStudent(sname, sgender);
}
@Override
public PageBean findStudentByPage(int currentPage) throws SQLException {
// TODO Auto-generated method stub
// 封装分页的该页的数据
PageBean<Student> pageBean = new PageBean<Student>();
int pageSize = StudentDao.PAGE_SIZE;
// 设置当前页
pageBean.setCurrentPage(currentPage);
// 每条记录
pageBean.setPageSize(pageSize);
StudentDao dao = new StudentDaoImpl();
List<Student> list = dao.findStudentByPage(currentPage);
pageBean.setList(list);
// 总记录数，总页数
int count = dao.findCount();
pageBean.setTotalSize(count);
// 总页数
pageBean.setTotalPage(count % pageSize == 0 ? count / pageSize : (count / pageSize) + 1);
return null;
}
}// 封装的数据
package com.dashucoding.domain;
import java.util.List;
// 一个用于封装了分页的数据
// 有： 当前学生集合数据，总的记录数，总的页数，当前页，每页的显示记录数
public class PageBean<T> {
private int currentPage; // 当前页
private int totalPage;// 总页数
private int pageSize;// 每页的记录数，每页要显示多少记录
private int totalSize; // 总的记录数
private List<T> list; // 当前页的学生集合
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getTotalSize() {
return totalSize;
}
public void setTotalSize(int totalSize) {
this.totalSize = totalSize;
}
public List<T> getList() {
return list;
}
public void setList(List<T> list) {
this.list = list;
}
}
效果
最后就靠显示页面逻辑
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学生列表页面</title>
<script type="text/javascript">
function doDelete(sid) {
/* 如果这里弹出的对话框，用户点击的是确定，就马上去请求Servlet。
如何知道用户点击的是确定。
如何在js的方法中请求servlet。 */
var flag = confirm("是否确定删除?");
if(flag){
//表明点了确定。 访问servlet。 在当前标签页上打开 超链接，
//window.location.href="DeleteServlet?sid="+sid;
location.href="DeleteServlet?sid="+sid;
}
}
</script>
</head>
<body>
<form action="SearchStudentServlet" method="post">
<table border="1" width="700">
<tr >
<td colspan="8">
按姓名查询:<input type="text" name="sname"/>
按性别查询:<select name="sgender">
<option value="">--请选择--
<option value="男">男
<option value="女">女
</select>
<input type="submit" value="查询">
<a href="add.jsp">添加</a>
</td>
</tr>
<tr align="center">
<td>编号</td>
<td>姓名</td>
<td>性别</td>
<td>电话</td>
<td>生日</td>
<td>爱好</td>
<td>简介</td>
<td>操作</td>
</tr>
<c:forEach items="${pageBean.list }" var="stu">
<tr align="center">
<td>${stu.sid }</td>
<td>${stu.sname }</td>
<td>${stu.gender }</td>
<td>${stu.phone }</td>
<td>${stu.birthday }</td>
<td>${stu.hobby }</td>
<td>${stu.info }</td>
<td><a href="EditServlet?sid=${stu.sid }">更新</a> <a href="#" onclick="doDelete(${stu.sid})">删除</a></td>
</tr>
</c:forEach>
<tr>
<td colspan="8">
第 ${pageBean.currentPage } / ${pageBean.totalPage }
每页显示${pageBean.pageSize }条
总的记录数${pageBean.totalSize }
<c:if test="${pageBean.currentPage !=1 }">
<a href="StudentListPageServlet?currentPage=1">首页</a>
| <a href="StudentListPageServlet?currentPage=${pageBean.currentPage-1 }">上一页</a>
</c:if>
<c:forEach begin="1" end="${pageBean.totalPage }" var="i">
<c:if test="${pageBean.currentPage == i }">
${i }
</c:if>
<c:if test="${pageBean.currentPage != i }">
<a href="StudentListPageServlet?currentPage=${i }">${i }</a>
</c:if>
</c:forEach>
<c:if test="${pageBean.currentPage !=pageBean.totalPage }">
<a href="StudentListPageServlet?currentPage=${pageBean.currentPage+1 }">下一页</a> |
<a href="StudentListPageServlet?currentPage=${pageBean.totalPage }">尾页</a>
</c:if>
</td>
</tr>
</table>
</form>
</body>
</html>
项目结构
我的源码
package com.dashucoding.dao;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.domain.Student;
/*
* 这是针对学生表的数据访问
*
* */
public interface StudentDao {
// 接口中定义的成员都是常量
// 一页显示多少条记录
int PAGE_SIZE = 5;
// 分页dao,查询当页的学生数据
List<Student> findStudentByPage(int currentPage) throws SQLException;
// 根据姓名或性别，查询
List<Student> searchStudent(String sname, String sgender) throws SQLException;
/*
* 查询所有学生 list<Student>
*/
List<Student> findAll() throws SQLException;
void insert(Student student) throws SQLException;
// sid根据id删除学生
void delete(int sid) throws SQLException;
// 根据id查询单个学生对象
Student findStudentById(int sid) throws SQLException;
// 更新学生信息
void update(Student student) throws SQLException;
// 查询总的学生记录数
int findCount() throws SQLException;
}package com.dashucoding.dao.impl;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import com.dashucoding.dao.StudentDao;
import com.dashucoding.domain.Student;
import com.dashucoding.util.JDBCUtil02;
import com.dashucoding.util.TextUtils;
/*
*这是StudentDao的实现,针对前面定义的规范,做出具体的实现
* */
public class StudentDaoImpl implements StudentDao {
/*
* 查询所有学生
*/
@Override
public List<Student> findAll() throws SQLException {
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
return runner.query("select * from stu", new BeanListHandler<Student>(Student.class));
}
@Override
public void insert(Student student) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
runner.update("insert into stu values(null, ?,?,?,?,?,?)",
student.getSname(),
student.getGender(),
student.getPhone(),
student.getBirthday(),
student.getHobby(),
student.getInfo()
);
}
@Override
public void delete(int sid) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
runner.update("delete from stu where sid=?", sid);
}
@Override
public Student findStudentById(int sid) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
return runner.query("select * from stu where sid = ?", new BeanHandler<Student>(Student.class), sid);
}
@Override
public void update(Student student) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
runner.update("update stu set sname=?, gender=?, phone=?, birthday=?, hobby=?, info=? where sid=?",
student.getSname(),
student.getGender(),
student.getPhone(),
student.getBirthday(),
student.getHobby(),
student.getInfo(),
student.getSid());
}
// 模糊查询
@Override
public List<Student> searchStudent(String sname, String sgender) throws SQLException {
// TODO Auto-generated method stub
/*System.out.println(sname + sgender);*/
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
/*
* String sql = "select * from stu where sname=? or sgender=?";
* select * from stu where sname like ?;
* select * from stu where gender = ?;
* select * from stu where sname like ? and gender = ?;
* 如果两个都没有就查询所有
* sql = "select * from stu"
* if(姓名){
* sql = sql + "where sname like ?";
* }
* if(性别){
* sql = sql + "where gender = ?";
* }
*
* String sql = "select * from stu where 1=1";
* if(姓名){
* sql = sql + " and sname like ? ";
* }
* if(性别){
* sql = sql + " and gender = ? ";
* }
* */
String sql = "select * from stu where 1=1";
List<String> list = new ArrayList<String>();
if(!TextUtils.isEmpty(sname)) {
sql = sql + " and sname like ? ";
list.add("%"+sname+"%");
}
if(!TextUtils.isEmpty(sgender)) {
sql = sql + " and gender = ? ";
list.add(sgender);
}
/*list.toArray()*/
return runner.query(sql, new BeanListHandler<Student>(Student.class),list.toArray());
}
@Override
public List<Student> findStudentByPage(int currentPage) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
// 第一个问号，一页返回多少条记录，第二个问号，跳过前面的多少条记录
//5 0 --- 第一页 (1-1)*5
//5 5 --- 第二页 (2-1)*5
//5 10 --- 第三页
return runner.query("select * from stu limit ? offset ?", new BeanListHandler<Student>(Student.class),PAGE_SIZE , (currentPage-1)*PAGE_SIZE);
}
// 查询总的记录数
@Override
public int findCount() throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
// 用于处理平均值，总的个数
Long result = (Long) runner.query("select count(*) from stu", new ScalarHandler());
return result.intValue();
}
}package com.dashucoding.domain;
import java.util.List;
// 一个用于封装了分页的数据
// 有： 当前学生集合数据，总的记录数，总的页数，当前页，每页的显示记录数
public class PageBean<T> {
private int currentPage; // 当前页
private int totalPage;// 总页数
private int pageSize;// 每页的记录数，每页要显示多少记录
private int totalSize; // 总的记录数
private List<T> list; // 当前页的学生集合
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getTotalSize() {
return totalSize;
}
public void setTotalSize(int totalSize) {
this.totalSize = totalSize;
}
public List<T> getList() {
return list;
}
public void setList(List<T> list) {
this.list = list;
}
}package com.dashucoding.domain;
import java.util.Date;
/*
* 这是学生封装的对象bean
*
* */
public class Student {
private int sid;
private String sname;
private String gender;
private String phone;
private String hobby;
private String info;
private Date birthday;
public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(int sid, String sname, String gender, String phone, String hobby, String info, Date birthday) {
super();
this.sid = sid;
this.sname = sname;
this.gender = gender;
this.phone = phone;
this.hobby = hobby;
this.info = info;
this.birthday = birthday;
}
public Student(String sname, String gender, String phone, String hobby, String info, Date birthday) {
super();
this.sname = sname;
this.gender = gender;
this.phone = phone;
this.hobby = hobby;
this.info = info;
this.birthday = birthday;
}
public int getSid() {
return sid;
}
public void setSid(int sid) {
this.sid = sid;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getHobby() {
return hobby;
}
public void setHobby(String hobby) {
this.hobby = hobby;
}
public String getInfo() {
return info;
}
public void setInfo(String info) {
this.info = info;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "Student [sid=" + sid + ", sname=" + sname + ", gender=" + gender + ", phone=" + phone + ", hobby="
+ hobby + ", info=" + info + ", birthday=" + birthday + "]";
}
}package com.dashucoding.service;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.domain.PageBean;
import com.dashucoding.domain.Student;
/*
* 这是学生的业务处理规范
* */
public interface StudentService {
// 分页dao,查询当页的学生数据
// 分页的很多小逻辑业务 可以做到service里面
// 业务做到service里面，做的就是bean了，当前页，总页数，显示条数， 总记录数
// 返回的是一个bean了
// 返回的是PageBean里面的所有数据了
PageBean findStudentByPage(int currentPage) throws SQLException;
// 根据姓名或性别，查询
List<Student> searchStudent(String sname, String sgender) throws SQLException;
/*
* 查询所有学生 list<Student>
*/
List<Student> findAll() throws SQLException;
void insert(Student student) throws SQLException;
// sid根据id删除学生
void delete(int sid) throws SQLException;
// 根据id查询单个学生对象
Student findStudentById(int sid) throws SQLException;
// 更新学生信息
void update(Student student) throws SQLException;
}package com.dashucoding.service.impl;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.dao.StudentDao;
import com.dashucoding.dao.impl.StudentDaoImpl;
import com.dashucoding.domain.PageBean;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
/*
* 这是学生业务实现
* */
public class StudentServiceImpl implements StudentService {
@Override
public List<Student> findAll() throws SQLException {
StudentDao dao = new StudentDaoImpl();
return dao.findAll();
}
@Override
public void insert(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.insert(student);
}
@Override
public void delete(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.delete(sid);
}
@Override
public Student findStudentById(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.findStudentById(sid);
}
@Override
public void update(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.update(student);
}
@Override
public List<Student> searchStudent(String sname, String sgender) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.searchStudent(sname, sgender);
}
@Override
public PageBean findStudentByPage(int currentPage) throws SQLException {
// TODO Auto-generated method stub
// 封装分页的该页的数据
PageBean<Student> pageBean = new PageBean<Student>();
int pageSize = StudentDao.PAGE_SIZE;
// 设置当前页
pageBean.setCurrentPage(currentPage);
// 每条记录
pageBean.setPageSize(pageSize);
StudentDao dao = new StudentDaoImpl();
List<Student> list = dao.findStudentByPage(currentPage);
pageBean.setList(list);
// 总记录数，总页数
int count = dao.findCount();
pageBean.setTotalSize(count);
// 总页数
pageBean.setTotalPage(count % pageSize == 0 ? count / pageSize : (count / pageSize) + 1);
return null;
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* 用于处理学生的添加请求
*/
public class AddServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
try {
// 1. 获取客户端提交上来的数据
String sname = request.getParameter("sname");
String gender = request.getParameter("gender");
String phone = request.getParameter("phone");
String birthday = request.getParameter("birthday");
String info = request.getParameter("info");
// String hobby = request.getParameter("hobby");//hobby : 游泳，写字， 足球。
String[] h = request.getParameterValues("hobby");
String hobby = Arrays.toString(h);
hobby = hobby.substring(1, hobby.length() - 1);
// 2. 添加到数据库
// string -- date
Date date = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);
Student student = new Student(sname, gender, phone, hobby, info, date);
StudentService service = new StudentServiceImpl();
service.insert(student);
// 3. 跳转到列表页
request.getRequestDispatcher("StudentListServlet").forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* 用于处理删除学生
*/
public class DeleteServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
int sid = Integer.parseInt(request.getParameter("sid"));
// System.out.println("sid="+sid);
// 执行删除
StudentService service = new StudentServiceImpl();
service.delete(sid);
// 跳转到列表页
request.getRequestDispatcher("StudentListServlet").forward(request, response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* 处理单个学生的更新，查询学生的信息，跳转到更新的页面
*/
public class EditServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
// 接收id
int sid = Integer.parseInt(request.getParameter("sid"));
// 查询学生数据
StudentService service = new StudentServiceImpl();
Student stu = service.findStudentById(sid);
// 显示数据
// 存储数据
request.setAttribute("stu", stu);
// 跳转
request.getRequestDispatcher("edit.jsp").forward(request, response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* Servlet implementation class SearchStudentServlet
*/
public class SearchStudentServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
try {
// 取到了要查询的关键数据
String sname = request.getParameter("sname");
String sgender = request.getParameter("sgender");
// 找service查询
StudentService service = new StudentServiceImpl();
List<Student> list = service.searchStudent(sname, sgender);
/*for(Student student : list) {
System.out.println("stu=" + student);
}*/
request.setAttribute("list", list);
// 跳转界面
request.getRequestDispatcher("list.jsp").forward(request, response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.PageBean;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* 这是用于分页显示学生列表的servlet
*/
public class StudentListPageServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
//1. 获取需要显示的页码数
int currentPage =Integer.parseInt( request.getParameter("currentPage"));
//2. 根据指定的页数，去获取该页的数据回来
//List<Student> --- list.jsp
StudentService service = new StudentServiceImpl();
PageBean pageBean= service.findStudentByPage(currentPage);
request.setAttribute("pageBean", pageBean);
//3. 跳转界面。
request.getRequestDispatcher("list_page.jsp").forward(request, response);
} catch (SQLException e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.dao.StudentDao;
import com.dashucoding.dao.impl.StudentDaoImpl;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
public class StudentListServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
// 查询所有的学生
StudentService service = new StudentServiceImpl();
List<Student> list = service.findAll();
// 把数据存储到作用域中
request.setAttribute("list", list);
// 跳转页面
request.getRequestDispatcher("list.jsp").forward(request,response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}package com.dashucoding.servlet;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
import com.dashucoding.service.impl.StudentServiceImpl;
/**
* Servlet implementation class UpdateServlet
*/
public class UpdateServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
try {
// 1. 获取客户端提交上来的数据
int sid = Integer.parseInt(request.getParameter("sid"));
String sname = request.getParameter("sname");
String gender = request.getParameter("gender");
String phone = request.getParameter("phone");
String birthday = request.getParameter("birthday");
String info = request.getParameter("info");
// String hobby = request.getParameter("hobby");
String[] h = request.getParameterValues("hobby");
String hobby = Arrays.toString(h);
hobby = hobby.substring(1, hobby.length() - 1);
// 2. 添加到数据库
Date date = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);
Student student = new Student(sid, sname, gender, phone, hobby, info, date);
// 2. 更新数据库数据
StudentService service = new StudentServiceImpl();
service.update(student);
// 3. 跳转界面
request.getRequestDispatcher("StudentListServlet").forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}package com.dashucoding.util;
import java.io.FileInputStream;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class JDBCUtil02 {
static ComboPooledDataSource dataSource = null;
static {
dataSource = new ComboPooledDataSource();
}
public static DataSource getDataSource() {
return dataSource;
}
/**
* 获取连接对象
* @return
* @throws SQLException
*/
public static Connection getConn() throws SQLException{
return dataSource.getConnection();
}
/**
* 释放资源
* @param conn
* @param st
* @param rs
*/
public static void release(Connection conn , Statement st , ResultSet rs){
closeRs(rs);
closeSt(st);
closeConn(conn);
}
public static void release(Connection conn , Statement st){
closeSt(st);
closeConn(conn);
}
private static void closeRs(ResultSet rs){
try {
if(rs != null){
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs = null;
}
}
private static void closeSt(Statement st){
try {
if(st != null){
st.close();
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
st = null;
}
}
private static void closeConn(Connection conn){
try {
if(conn != null){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
conn = null;
}
}
}package com.dashucoding.util;
public class TextUtils {
/**
* 判断某一个字符串是否为空。
*
* @param s
* @return
*/
public static boolean isEmpty(CharSequence s) {
return s == null || s.length() == 0;
}
}<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>添加学生页面</title>
</head>
<body>
<form method="post" action="AddServlet">
<table border="1" width="600">
<tr>
<td>姓名</td>
<td><input type="text" name="sname"></td>
</tr>
<tr>
<td>性别</td>
<td><input type="radio" name="gender" value="男">男 <input
type="radio" name="gender" value="女">女</td>
</tr>
<tr>
<td>电话</td>
<td><input type="text" name="phone"></td>
</tr>
<tr>
<td>生日</td>
<td><input type="text" name="birthday"></td>
</tr>
<tr>
<td>爱好</td>
<td><input type="checkbox" name="hobby" value="游泳">游泳 <input
type="checkbox" name="hobby" value="篮球">篮球 <input
type="checkbox" name="hobby" value="足球">足球 <input
type="checkbox" name="hobby" value="看书">看书 <input
type="checkbox" name="hobby" value="写字">写字</td>
</tr>
<tr>
<td>简介</td>
<td><textarea name="info" rows="3" cols="20"></textarea></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="添加"></td>
</tr>
</table>
</form>
</body>
</html><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>更新学生页面</title>
</head>
<body>
<h3>更新学生页面</h3>
<form method="post" action="UpdateServlet">
<input type="hidden" name="sid" value="${stu.sid }">
<table border="1" width="600">
<tr>
<td>姓名</td>
<td><input type="text" name="sname" value="${stu.sname }"></td>
</tr>
<tr>
<td>性别</td>
<td>
<input type="radio" name="gender" value="男" <c:if test="${stu.gender == '男'}">checked</c:if>>男
<input type="radio" name="gender" value="女" <c:if test="${stu.gender == '女'}">checked</c:if>>女
</td>
</tr>
<tr>
<td>电话</td>
<td><input type="text" name="phone" value="${stu.phone }"></td>
</tr>
<tr>
<td>生日</td>
<td><input type="text" name="birthday" value="${stu.birthday }"></td>
</tr>
<tr>
<td>爱好</td>
<td>
<input type="checkbox" name="hobby" value="游泳" <c:if test="${fn:contains(stu.hobby,'游泳') }">checked</c:if>>游泳
<input type="checkbox" name="hobby" value="篮球" <c:if test="${fn:contains(stu.hobby,'篮球') }">checked</c:if>>篮球
<input type="checkbox" name="hobby" value="足球" <c:if test="${fn:contains(stu.hobby,'足球') }">checked</c:if>>足球
<input type="checkbox" name="hobby" value="看书" <c:if test="${fn:contains(stu.hobby,'看书') }">checked</c:if>>看书
<input type="checkbox" name="hobby" value="写字" <c:if test="${fn:contains(stu.hobby,'写字') }">checked</c:if>>写字
</td>
</tr>
<tr>
<td>简介</td>
<td><textarea name="info" rows="3" cols="20">${stu.info }</textarea></td>
</tr>
<tr>
<td colspan="2"> <input type="submit" value="更新"> </td>
</tr>
</table>
</form>
</body>
</html><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
</head>
<body>
<h3><a href="StudentListServlet">显示所有学生列表</a></h3><br>
<h3><a href="StudentListPageServlet?currentPage=1">分页显示所有学生</a></h3>
</body>
</html><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学生列表页面</title>
<script type="text/javascript">
function doDelete(sid) {
// 弹出对话框，点击确定，请求Servlet
var flag = confirm("是否确定删除?");
if(flag){
//访问servlet
//window.location.href="DeleteServlet?sid="+sid;
location.href="DeleteServlet?sid="+sid;
}
}
</script>
</head>
<body>
<form action="SearchStudentServlet" method="post">
<table border="1" width="700">
<tr >
<td colspan="8">
按姓名查询:<input type="text" name="sname"/>
按性别查询:<select name="sgender">
<option value="">--请选择--
<option value="男">男
<option value="女">女
</select>
<input type="submit" value="查询">
<a href="add.jsp">添加</a>
</td>
</tr>
<tr align="center">
<td>编号</td>
<td>姓名</td>
<td>性别</td>
<td>电话</td>
<td>生日</td>
<td>爱好</td>
<td>简介</td>
<td>操作</td>
</tr>
<c:forEach items="${list }" var="stu">
<tr align="center">
<td>${stu.sid }</td>
<td>${stu.sname }</td>
<td>${stu.gender }</td>
<td>${stu.phone }</td>
<td>${stu.birthday }</td>
<td>${stu.hobby }</td>
<td>${stu.info }</td>
<td><a href="EditServlet?sid=${stu.sid }">更新</a> <a href="#" onclick="doDelete(${stu.sid})">删除</a></td>
</tr>
</c:forEach>
</table>
</form>
</body>
</html><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学生列表页面</title>
<script type="text/javascript">
function doDelete(sid) {
// 弹出对话框，点击确定，请求Servlet
var flag = confirm("是否确定删除?");
if(flag){
//访问servlet
//window.location.href="DeleteServlet?sid="+sid;
location.href="DeleteServlet?sid="+sid;
}
}
</script>
</head>
<body>
<form action="SearchStudentServlet" method="post">
<table border="1" width="700">
<tr>
<td colspan="8">按姓名查询:<input type="text" name="sname" />
按性别查询:<select name="sgender">
<option value="">--请选择--
<option value="男">男
<option value="女">女
</select> <input type="submit" value="查询">
<a href="add.jsp">添加</a>
</td>
</tr>
<tr align="center">
<td>编号</td>
<td>姓名</td>
<td>性别</td>
<td>电话</td>
<td>生日</td>
<td>爱好</td>
<td>简介</td>
<td>操作</td>
</tr>
<c:forEach items="${pageBean.list }" var="stu">
<tr align="center">
<td>${stu.sid }</td>
<td>${stu.sname }</td>
<td>${stu.gender }</td>
<td>${stu.phone }</td>
<td>${stu.birthday }</td>
<td>${stu.hobby }</td>
<td>${stu.info }</td>
<td><a href="EditServlet?sid=${stu.sid }">更新</a> <a href="#"
onclick="doDelete(${stu.sid})">删除</a></td>
</tr>
</c:forEach>
<tr>
<td colspan="8">第 ${pageBean.currentPage } /
${pageBean.totalPage } 每页显示${pageBean.pageSize }条
总的记录数${pageBean.totalSize } <c:if
test="${pageBean.currentPage !=1 }">
<a href="StudentListPageServlet?currentPage=1">首页</a>
| <a
href="StudentListPageServlet?currentPage=${pageBean.currentPage-1 }">上一页</a>
</c:if> <c:forEach begin="1" end="${pageBean.totalPage }" var="i">
<c:if test="${pageBean.currentPage == i }">
${i }
</c:if>
<c:if test="${pageBean.currentPage != i }">
<a href="StudentListPageServlet?currentPage=${i }">${i }</a>
</c:if>
</c:forEach> <c:if test="${pageBean.currentPage !=pageBean.totalPage }">
<a
href="StudentListPageServlet?currentPage=${pageBean.currentPage+1 }">下一页</a> |
<a
href="StudentListPageServlet?currentPage=${pageBean.totalPage }">尾页</a>
</c:if>
</td>
</tr>
</table>
</form>
</body>
</html>
效果
package com.dashucoding.service.impl;
import java.sql.SQLException;
import java.util.List;
import com.dashucoding.dao.StudentDao;
import com.dashucoding.dao.impl.StudentDaoImpl;
import com.dashucoding.domain.PageBean;
import com.dashucoding.domain.Student;
import com.dashucoding.service.StudentService;
/*
* 这是学生业务实现
* */
public class StudentServiceImpl implements StudentService {
@Override
public List<Student> findAll() throws SQLException {
StudentDao dao = new StudentDaoImpl();
return dao.findAll();
}
@Override
public void insert(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.insert(student);
}
@Override
public void delete(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.delete(sid);
}
@Override
public Student findStudentById(int sid) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.findStudentById(sid);
}
@Override
public void update(Student student) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
dao.update(student);
}
@Override
public List<Student> searchStudent(String sname, String sgender) throws SQLException {
// TODO Auto-generated method stub
StudentDao dao = new StudentDaoImpl();
return dao.searchStudent(sname, sgender);
}
@Override
public PageBean findStudentByPage(int currentPage) throws SQLException {
// 封装分页的该页数据
PageBean<Student> pageBean = new PageBean<Student>();
int pageSize = StudentDao.PAGE_SIZE;
pageBean.setCurrentPage(currentPage);
// 设置当前页
pageBean.setPageSize(pageSize);
// 设置每页显示多少记录
StudentDao dao = new StudentDaoImpl();
List<Student> list = dao.findStudentByPage(currentPage);
pageBean.setList(list);
// 设置这一页的学生数据
// 总的记录数， 总的页数。
int count = dao.findCount();
pageBean.setTotalSize(count);
// 设置总的记录数
pageBean.setTotalPage(count % pageSize == 0 ? count / pageSize : (count / pageSize) + 1); // 总页数
return pageBean;
}
}结言
好了，欢迎在留言区留言，与大家分享你的经验和心得。
感谢你学习今天的内容，如果你觉得这篇文章对你有帮助的话，也欢迎把它分享给更多的朋友，感谢。
达叔小生：往后余生，唯独有你 You and me, we are family ! 90后帅气小伙，良好的开发习惯；独立思考的能力；主动并且善于沟通 简书博客： 达叔小生 https://www.jianshu.com/u/c785ece603d1
结语
- 下面我将继续对 其他知识 深入讲解 ，有兴趣可以继续关注
- 小礼物走一走 or 点赞
本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
原始发表：2019.02.05 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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数据保险箱
数据保险箱（Cloud Data Coffer Service，CDCS）为您提供更高安全系数的企业核心数据存储服务。您可以通过自定义过期天数的方法删除数据，避免误删带来的损害，还可以将数据跨地域存储，防止一些不可抗因素导致的数据丢失。数据保险箱支持通过控制台、API 等多样化方式快速简单接入，实现海量数据的存储管理。您可以使用数据保险箱对文件数据进行上传、下载，最终实现数据的安全存储和提取。
腾讯云开发者
