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;

// 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;

SELECT * FROM stu LIMIT 5 , 5;

SELECT * FROM stu LIMIT 5 , 2;

SELECT * FROM stu LIMIT 2 , 5;

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;

// 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;

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;
	}
	
	
}

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"/>
					&nbsp;
					按性别查询:<select name="sgender">
								<option value="">--请选择--
								<option value="男">男
								<option value="女">女
							  </select>
					&nbsp;&nbsp;&nbsp;
					<input type="submit" value="查询">
					&nbsp;&nbsp;&nbsp;
					<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 } / ${pageBean.totalPage }
			  		&nbsp;&nbsp;
			  		每页显示${pageBean.pageSize }条  &nbsp;&nbsp;&nbsp;
			  		总的记录数${pageBean.totalSize } &nbsp;&nbsp;&nbsp;
			  		
			  		<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>

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"/>
					&nbsp;
					按性别查询:<select name="sgender">
								<option value="">--请选择--
								<option value="男">男
								<option value="女">女
							  </select>
					&nbsp;&nbsp;&nbsp;
					<input type="submit" value="查询">
					&nbsp;&nbsp;&nbsp;
					<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" /> &nbsp;
					按性别查询:<select name="sgender">
						<option value="">--请选择--
						<option value="男">男
						<option value="女">女
				</select> &nbsp;&nbsp;&nbsp; <input type="submit" value="查询">
					&nbsp;&nbsp;&nbsp; <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 } /
					${pageBean.totalPage } &nbsp;&nbsp; 每页显示${pageBean.pageSize }条
					&nbsp;&nbsp;&nbsp; 总的记录数${pageBean.totalSize } &nbsp;&nbsp;&nbsp; <c:if
						test="${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>

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

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