专栏首页达达前端第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

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"/>
                    &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>

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"/>
                    &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>

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
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