JavaWeb实现学生管理系统

JavaWeb实现学生管理系统

  • 一、项目介绍
  • 二、项目结构
  • 三、前期准备
    • 1.配置maven环境,在pom.xml配置文件中配置项目所依赖的jar包
    • 2.在MySql数据库中,创建登录注册表login和学生信息表student
      • (1)登录注册表login
      • (2)学生信息表student
      • (3)创建数据表代码
    • 3.配置tocamt
  • 四、代码实现
    • 1.JSP界面实现
      • (1)首页-登录界面 (index.jsp)
      • (2)用户注册界面 (register.jsp)
      • (3)登录成功-主界面 (main.jsp)
      • (4)添加学生界面 (addStudent.jsp)
      • (5)分页查询界面(showAllStudentByPageNo.jsp)
      • (6)查看所有学生信息界面
      • (7) 修改学生界面 (updateStudent.jsp)
    • 2.JavaBean实体类封装数据
      • (1)学生信息类 (Student.java)
      • (2)分页帮助类 (Page.java)
      • (3)JDBC工具类 (DBTools.java)
    • 3.三层架构
      • (1)表示层servlet
        • ① 用户登录表示层 (LoginServlet.java)
        • ② 用户注册表示层 (RegisterServlet.java)
        • ③ 分页查询表示层 (ShowStudentsByPageServlet.java)
        • ④ 查询所学生信息表示层 (ShowAllStudentsServlet.java)
        • ⑤ 添加学生表示层 (AddServlet.java)
        • ⑥ 删除学生表示层 (DeleteServlet.java)
        • ⑦ 根据学号查询学生信息表示层 (QueryStudentBySnoSevlet.java)
        • ⑧ 修改学生信息表示层 (UpdateServlet.java)
        • ⑨ 退出登录表示层 (QuitServlet.java)
      • (2)业务逻辑层service
        • ① Service接口(StudentService.java)
        • ② 接口的实现类(StudentServiceImpl.java)
      • (3)数据访问层dao
        • ① 接口(StudentDao.java)
        • ② 接口的实现类(StudentDaoImpl.java)

一、项目介绍

该项目是基于JavaWeb实现的学生管理系统,使用maven进行管理jar包,能够对学生信息进行增删改查,分页查询,以及实现管理员的注册、登录

数据库:MySQL

开发工具:idea

开发环境:jdk 1.8 + tomcat

二、项目结构

在这里插入图片描述在这里插入图片描述

三、前期准备

1.配置maven环境,在pom.xml配置文件中配置项目所依赖的jar包

    
      mysql
      mysql-connector-java
      8.0.21
    

    
      javax.servlet
      javax.servlet-api
      3.0.1
      provided
    

    
      javax.servlet.jsp
      jsp-api
      2.2
      provided
    

2.在MySql数据库中,创建登录注册表login和学生信息表student

(1)登录注册表login

在这里插入图片描述

(2)学生信息表student

在这里插入图片描述

(3)创建数据表代码

SET NAMES utf-8;
CREATE DATABASE studentManager;
USE studentManager;
CREATE TABLE student
(
  sno INT PRIMARY KEY,
  sname VARCHAR(20) NOT NULL,
  sex CHAR(4) ,
  age INT DEFAULT 20,
  phone VARCHAR(30) 
);

INSERT INTO student VALUES(1001,'jack','男',23,'13389076524');
INSERT INTO student VALUES(1002,'rose','女',23,'18760987543');
INSERT INTO student VALUES(1003,'tom','男',23,'13389067823');
INSERT INTO student VALUES(1004,'王麻子','男',23,'13560738947');
INSERT INTO student VALUES(1005,'大麻子','男',23,'18899067532');

INSERT INTO student VALUES(1006,'小麻子','男',23,'15678634789');
INSERT INTO student VALUES(1007,'老麻子','男',23,'12199834572');
INSERT INTO student VALUES(1008,'张三','男',23,'15533098843');
INSERT INTO student VALUES(1009,'长萨珊','女',23,'12209835679');
INSERT INTO student VALUES(1010,'李四','女',23,'15509087635');

INSERT INTO student VALUES(1011,'王五','男',23,'15788679043');
INSERT INTO student VALUES(1012,'赵六','女',23,'12489034506');
INSERT INTO student VALUES(1013,'刘二','男',23,'13560596743');

CREATE TABLE login
(
  uid INT PRIMARY KEY,
  pwd VARCHAR(20) NOT NULL,
);

INSERT INTO login VALUES(1, '1234');
INSERT INTO login VALUES(2, '2222');
INSERT INTO login VALUES(3, '6688');

3.配置tocamt

在这里插入图片描述在这里插入图片描述

四、代码实现

1.JSP界面实现

(1)首页-登录界面 (index.jsp)

<%@ page language="java" contentType="text/html; charset=utf-8"  pageEncoding="utf-8"%>



    学生信息管理平台
    








    学生信息管理平台

    
用户登录 立即注册 <% if(session.getAttribute("loginErrorMessage") != null){ String loginErrorMessage = (String)session.getAttribute("loginErrorMessage"); out.print(loginErrorMessage); } %> <% String register = (String) request.getAttribute("register"); if (register!= null) { if (register.equals("reg")) { out.println("注册成功, 请登录!"); } } %>

(2)用户注册界面 (register.jsp)

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>



    注册账号

    





    学生信息管理平台
    
用户注册 返回

(3)登录成功-主界面 (main.jsp)

<%@ page language="java" contentType="text/html; charset=utf-8"  pageEncoding="utf-8"%>
<%@ page import="com.stu.po.Student" %>



    学生信息管理平台

    



    欢迎进入学生信息管理平台
    <%
        if(session.getAttribute("login") == null) {
            session.setAttribute("loginErrorMessage", "您必须先登录才能访问主页!");
            response.sendRedirect("index.jsp");
        }
    %>
    
        添加学生
        分页查询
        查看所有学生信息
        退出登录
    



(4)添加学生界面 (addStudent.jsp)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>



    添加学生信息

    




    学生信息管理平台
    
添加学生信息 返回

(5)分页查询界面(showAllStudentByPageNo.jsp)

<%@ page import="com.stu.po.Student" %>
<%@ page import="java.util.List" %>
<%@ page import="com.stu.po.Page" %>
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>




  学生信息管理平台

  



  分页查询学生信息
    
      
        <%
          Page page1 = (Page)request.getAttribute("page1");

          for(Student student:page1.getStudent()){

        %>
            
          <%
            }
          %>
      

学号

姓名

性别

年龄

电话

<%=student.getSno() %> <%=student.getSname() %> <%=student.getSex() %> <%=student.getAge() %> <%=student.getPhone() %>
<% if(page1.getCurrentPage()==page1.getTotalPage()){ %> 首页 ">上一页 <% } else if(page1.getCurrentPage()==0){ %> ">下一页 ">尾页 <% } else{ %> 首页 ">上一页 ">下一页 ">尾页 <% } %> 返回

(6)查看所有学生信息界面

<%@ page language="java" contentType="text/html; charset=utf-8"  pageEncoding="utf-8"%>
<%@ page import="com.stu.po.Student" %>
<%@ page import="java.util.List" %>



	学生信息管理平台

	



	查看所有学生信息
	
		
			<%

				List allStudents = (List)session.getAttribute("allStudents");
				for (int i = 0; i < allStudents.size(); i++) {
					Student s  = allStudents.get(i);
			%>
			
			<%
				}
			%>
		

学号

姓名

性别

年龄

电话

操作

<%=s.getSno() %> <%=s.getSname() %> <%=s.getSex() %> <%=s.getAge() %> <%=s.getPhone() %> ">删除 ">修改
返回

(7) 修改学生界面 (updateStudent.jsp)

<%@ page language="java" contentType="text/html; charset=utf-8"  pageEncoding="utf-8"%>
<%@ page import="com.stu.po.Student" %>



    
    
    
    修改学生信息

    




    学生信息管理平台

    
<% Student s =(Student)request.getAttribute("student"); %> 修改学生信息 返回

2.JavaBean实体类封装数据

(1)学生信息类 (Student.java)

package com.stu.po;

public class Student {
    //这是一个实体类,javabean

    private int sno;
    private String sname;
    private String sex;
    private int age;
    private String phone;

    public Student(int sno, String sname, String sex, int age, String phone) {
        this.sno = sno;
        this.sname = sname;
        this.sex = sex;
        this.age = age;
        this.phone = phone;
    }

    public Student() {

    }

    public int getSno() {
        return sno;
    }

    public void setSno(int sno) {
        this.sno = sno;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }
}

(2)分页帮助类 (Page.java)

package com.stu.po;

import java.util.List;

//分页帮助类
public class Page {
    private int currentPage;  //当前页面
    private int pageSize;     //一页有多少条数据
    private int totalCount;   //一共有多少条数据
    private int totalPage;    //一共有多少页
    private List student;
    public Page() {

    }
    public Page(int currentPage, int pageSize, int totalCount, int totalPage, List student) {
        this.currentPage = currentPage;
        this.pageSize = pageSize;
        this.totalCount = totalCount;
        this.totalPage = totalPage;
        this.student = student;
    }

    public int getCurrentPage() {
        return currentPage;
    }

    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public int getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }

    public int getTotalPage() {
        return totalPage;
    }

    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }

    public List getStudent() {
        return student;
    }

    public void setStudent(List student) {
        this.student = student;
    }
}

(3)JDBC工具类 (DBTools.java)

package com.stu.utils;

public interface DBTools {
    public static final String DRIVER_CLASS = "com.mysql.jdbc.Driver";
    public static final String CONN_STR = "jdbc:mysql://localhost:3306/studentmanager?userSSL=false&serverTimezone=Asia/Shanghai";
    public static final String USRENAME = "root";
    public static final String PWD = "123456";

}

3.三层架构

(1)表示层servlet

① 用户登录表示层 (LoginServlet.java)
package com.stu.servlet;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        StudentService service = new StudentServiceImpl();
        HttpSession session = request.getSession();

        if (session.getAttribute("loginErrorMessage") != null) {
            session.invalidate();
        }
        String uid = request.getParameter("uid");
        String pwd = request.getParameter("pwd");


        int _uid = Integer.parseInt(uid);
        boolean result = service.login(_uid, pwd);

        if(result){
            session.setAttribute("login", "log");
            response.sendRedirect("main.jsp");
        }else{
            response.sendRedirect("index.jsp");
        }

    }

}

② 用户注册表示层 (RegisterServlet.java)
package com.stu.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

@WebServlet("/RegisterServlet")
public class RegisterServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        StudentService service = new StudentServiceImpl();
        String uid = request.getParameter("uid");
        String pwd = request.getParameter("pwd");
        int _uid = Integer.parseInt(uid);
        boolean result = service.addLogin(_uid,pwd);

        if(!result) {
            request.setAttribute("register", "reg");
            request.getRequestDispatcher("index.jsp").forward(request, response);
        }else {
            request.getRequestDispatcher("register.jsp").forward(request, response);
        }

    }

}

③ 分页查询表示层 (ShowStudentsByPageServlet.java)
package com.stu.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.stu.po.Page;
import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

@WebServlet("/ShowStudentsByPageServlet")
public class ShowStudentsByPageServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StudentService Service = new StudentServiceImpl();
        int count = Service.getTotalCount();

        Page page = new Page();


        String currentPage = request.getParameter("currentPage");

        if(currentPage == null) {
            currentPage = "0";
        }
        int _currentPage = Integer.parseInt(currentPage);
        page.setCurrentPage(_currentPage);

        int totalCount = Service.getTotalCount();
        page.setTotalCount(totalCount);


        int pageSize = 5;
        int totalPage = (totalCount / pageSize) + 1;
        page.setTotalPage(totalPage+1);


        page.setPageSize(pageSize);

        List student = Service.queryStudentsByPageNo(_currentPage, pageSize);
        page.setStudent(student);

        request.setAttribute("page1", page);
        request.getRequestDispatcher("showAllStudentsByPageNo.jsp").forward(request, response);
    }

}

④ 查询所学生信息表示层 (ShowAllStudentsServlet.java)
package com.stu.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

@WebServlet("/ShowAllStudentsServlet")
public class ShowAllStudentsServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StudentService service = new StudentServiceImpl();
        HttpSession  session =   request.getSession();
        List allStudents = service.getAllStudents();
        session.setAttribute("allStudents", allStudents);
        response.sendRedirect("showAllStudents.jsp");
    }

}

⑤ 添加学生表示层 (AddServlet.java)
package com.stu.servlet;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/AddServlet")
public class AddServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        StudentService service = new StudentServiceImpl();
        String sno  = request.getParameter("sno");
        String sname  = request.getParameter("sname");
        String sex  = request.getParameter("sex");
        String age  = request.getParameter("age");
        String phone  = request.getParameter("phone");

        int _sno = 0;
        if(sno != null || "".equals(sno)){
            _sno = Integer.parseInt(sno);
        }

        int _age = 0;
        if (age !=null || "".equals(age)){
            _age = Integer.parseInt(age);
        }

        Student s = new Student(_sno, sname, sex, _age, phone);
        int result = service.addStudent(s);

        HttpSession session = request.getSession();
        session.setAttribute("student", "stu");
        response.sendRedirect("main.jsp");

    }
}

⑥ 删除学生表示层 (DeleteServlet.java)
package com.stu.servlet;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


@WebServlet("/DeleteServlet")
public class DeleteServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取sno
        String sno = request.getParameter("sno");

        int _sno = 0;
        if(sno != null && !"".equals(sno)){
            _sno = Integer.parseInt(sno);
        }

        //2.执行删除
        StudentService service = new StudentServiceImpl();
        Student stu = service.deleteStudent(_sno);
        //3.跳转到列表页
        request.setAttribute("stu", stu);
        request.getRequestDispatcher("ShowAllStudentsServlet").forward(request,response);
    }
}

⑦ 根据学号查询学生信息表示层 (QueryStudentBySnoSevlet.java)
package com.stu.servlet;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.io.IOException;



@WebServlet("/QueryStudentBySnoServlet")
public class QueryStudentBySnoServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取sno;
        String sno = request.getParameter("sno");
        int _sno = 0;
        if(sno != null && !"".equals(sno)){
            _sno = Integer.parseInt(sno);
        }

        //2.查询学生数据
        StudentService service = new StudentServiceImpl();
        Student student = service.queryStudentBySno(_sno);

        //3.显示数据
        //存数据
        request.setAttribute("student", student);
        //跳转
        request.getRequestDispatcher("updateStudent.jsp").forward(request,response);

    }
}

⑧ 修改学生信息表示层 (UpdateServlet.java)
package com.stu.servlet;

import com.stu.po.Student;
import com.stu.service.StudentService;
import com.stu.service.StudentServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;

@WebServlet("/UpdateServlet")
public class UpdateServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse resp) throws ServletException, IOException {

        String sno = request .getParameter("sno");
        String sname  = request.getParameter("sname");
        String sex  = request.getParameter("sex");
        String age  = request.getParameter("age");
        String phone  = request.getParameter("phone");

        int _sno = 0;
        if(sno != null && !"".equals(sno)){
            _sno = Integer.parseInt(sno);
        }
        int _age = 0;
        if(age != null && !"".equals(age)){
            _age = Integer.parseInt(age);
        }


        Student stu = new Student(_sno, sname, sex, _age, phone);

        StudentService service = new StudentServiceImpl();
        service.updateStudentBySno(_sno,stu);

        //3.跳转界面
        request.getRequestDispatcher("ShowAllStudentsServlet").forward(request, resp);

    }
}

⑨ 退出登录表示层 (QuitServlet.java)
package com.stu.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;


@WebServlet("/QuitServlet")
public class QuitServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession  session =   request.getSession();
        session.invalidate();//清空session对象中的所有属性数据内容
        resp.sendRedirect("index.jsp");
    }
}


(2)业务逻辑层service

① Service接口(StudentService.java)
package com.stu.service;

import java.util.List;

import com.stu.po.Student;

public interface StudentService {

    //service表示业务逻辑层,定义的每一个方法实际上对应的就是用户的一个需求(请求)

    public boolean login(int uid,String pwd);

    public boolean addLogin(int uid, String pwd);

    public List getAllStudents();

    public List queryStudentsByPageNo(int current, int pageSize);

    public Student deleteStudent(int sno);

    public Student queryStudentBySno(int sno);

    public int updateStudentBySno(int sno, Student stu) ;

    public int getTotalCount();

    public int addStudent(Student student);
    
}

② 接口的实现类(StudentServiceImpl.java)
package com.stu.service;

import java.util.List;
import com.stu.dao.StudentDao;
import com.stu.dao.StudentDaoImpl;
import com.stu.po.Student;

public class StudentServiceImpl implements StudentService {

    StudentDao dao = new StudentDaoImpl();

    //登陆
    @Override
    public boolean login(int uid, String pwd) {
        return dao.login(uid, pwd);
    }

    // 注册
    @Override
    public boolean addLogin(int uid, String pwd){
        return dao.addLogin(uid, pwd);
    }

    // 查询所有学生
    @Override
    public List getAllStudents() {
        return dao.getAllStudents();
    }

    // 分页查询
    @Override
    public List queryStudentsByPageNo(int current, int pageSize) {
        return dao.queryStudentByPage(current,pageSize);
    }

    // 删除学生
    @Override
    public Student deleteStudent(int sno){
        return dao.deleteStudent(sno);
    }

    // 修改学生信息,要先根据学号查询学生信息
    public Student queryStudentBySno(int sno) {
        return dao.queryStudentBySno(sno);

    }

    //更改学生信息
    public int updateStudentBySno(int sno, Student stu) {
        return dao.updateStudentBySno(sno,stu);
    }
    
    //查询总条数
    @Override
    public int getTotalCount() {
        return dao.getTotalCount();
    }

    @Override
    public int addStudent(Student student) {
        return dao.addStudent(student);
    }
    
}

(3)数据访问层dao

① 接口(StudentDao.java)
package com.stu.dao;

import java.util.List;

import com.stu.po.Student;

public interface StudentDao {

    public boolean login(int uid ,String pwd);

    public boolean addLogin(int uid, String pwd);

    public List getAllStudents();

    public List queryStudentByPage(int currentPage,int pageSize);

    public Student deleteStudent(int sno);

    public Student queryStudentBySno(int sno);

    public int updateStudentBySno(int sno,Student stu);

    //查询总数据数
    public int getTotalCount();

    public int addStudent(Student student);
   
}

② 接口的实现类(StudentDaoImpl.java)
package com.stu.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.stu.po.Student;
import com.stu.utils.DBTools;

public class StudentDaoImpl implements StudentDao {

    Connection conn = null; // 连接对象
    Statement st = null; // 语句对象
    ResultSet rs = null; // 结果集合对象

    @Override
    public boolean login(int uid, String pwd) {
        // 在这里需要连接数据库,根据int sno, String pwd这两个参数来查询student表
        // jdbc
        // 1:配置环境,下载数据库连接驱动jar文件,拷贝到项目中来
        // 2:加载驱动,根据驱动创建数据库的连接对象

        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            // 3:执行sql语句,完成对数据库中表的数据的增删该查。必须创建一个语句对象(执行sql语句的)
            st = conn.createStatement();

            int count = 0;
            String sqlStr = "select * from login where uid =" + uid + " and pwd = '" + pwd + "'";

            rs = st.executeQuery(sqlStr);
            while(rs.next()) {
                count++;
            }
            if(count>0)
                return true;
            else
                return false;

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }


    @Override
    public List getAllStudents() {
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            // 3:执行sql语句,完成对数据库中表的数据的增删该查。必须创建一个语句对象(执行sql语句的)
            st = conn.createStatement();

            String sqlStr = "select * from student";

            rs = st.executeQuery(sqlStr);

            List allStudents = new ArrayList();

            while (rs.next()) {
                int _sno = rs.getInt(1);
                String _sname = rs.getString(2);
                String _sex = rs.getString(3);
                int _age = rs.getInt(4);
                String _phone = rs.getString(5);
                Student s = new Student(_sno, _sname, _sex, _age, _phone);
                allStudents.add(s);
            }

            return allStudents;

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }

        return null;
    }


    public List queryStudentByPage(int current, int pageSize) {
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            // 3:执行sql语句,完成对数据库中表的数据的增删该查。必须创建一个语句对象(执行sql语句的)
            st = conn.createStatement();

            int startPosition = current * pageSize;

            String sqlStr = "select * from student limit " + startPosition + "," + pageSize;
            rs = st.executeQuery(sqlStr);
            List allStudents = new ArrayList();
            while (rs.next()) {
                int _sno = rs.getInt(1);
                String _sname = rs.getString(2);
                String _sex = rs.getString(3);
                int _age = rs.getInt(4);
                String _phone = rs.getString(5);
                Student s = new Student(_sno, _sname, _sex, _age, _phone);
                allStudents.add(s);
            }
            return allStudents;
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }

        return null;
    }

    public int getTotalCount() {//查询总数据数

        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            // 3:执行sql语句,完成对数据库中表的数据的增删该查。必须创建一个语句对象(执行sql语句的)
            st = conn.createStatement();
            String sql = "select count(*) from student";
            rs = st.executeQuery(sql);
            while (rs.next()){
                int totalCount = rs.getInt(1);
            }


        }catch (Exception e){
            e.printStackTrace();
        }
        return 0;
    }

    @Override
    public int addStudent(Student student) {

        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            st = conn.createStatement();
            String sqlStr = "insert into student values("+student.getSno()+",'" + student.getSname()+ "','" + student.getSex() +"',"+student.getAge()+",'"+student.getPhone()+"')";
            System.out.println(sqlStr);
            int result = st.executeUpdate(sqlStr);

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return 0;
    }


    @Override
    public boolean addLogin(int uid, String pwd) {
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            st = conn.createStatement();
            String sqlStr = "insert into login values(" + uid + ",'" + pwd + "')";

            int result = st.executeUpdate(sqlStr);

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }


    @Override
    public Student deleteStudent(int sno) {
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动
            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            st = conn.createStatement();
            String sqlStr = "delete from student where sno = " + sno;
            System.out.println(sqlStr);
            int result = st.executeUpdate(sqlStr);

        } catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

    @Override
    public Student queryStudentBySno(int sno) {
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动

            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);

            st = conn.createStatement();

            String sqlStr = "select * from student where sno = "+ sno;
            rs = st.executeQuery(sqlStr);

            if (rs.next()) {
                int _sno = rs.getInt(1);
                String _sname = rs.getString(2);
                String _sex = rs.getString(3);
                int _age = rs.getInt(4);
                String _phone = rs.getString(5);
                Student s = new Student(_sno, _sname, _sex, _age, _phone);
                return s;
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }


    @Override
    public int updateStudentBySno(int sno, Student stu){
        try {
            Class.forName(DBTools.DRIVER_CLASS);// 加载驱动
            conn = DriverManager.getConnection(DBTools.CONN_STR, DBTools.USRENAME, DBTools.PWD);
            st = conn.createStatement();
            String sql = "update student set sname= '"+stu.getSname()+"', sex='"+stu.getSex()+"', age="+stu.getAge()+", phone='"+stu.getPhone()+"' where sno="+sno;
            System.out.println(sql);
            int result = st.executeUpdate(sql);

        } catch (Exception e){
            e.printStackTrace();
        }
        return 0;
    }
}

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