mysql      mysql-connector-java      8.0.21              javax.servlet      javax.servlet-api      3.0.1      provided              javax.servlet.jsp      jsp-api      2.2      provided    

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');

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

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>        
    
学生信息管理平台
    
        
            
用户注册
            
                            
            
                            
                        返回        
    

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

<%@ page contentType="text/html;charset=UTF-8" language="java" %>        
    
学生信息管理平台
    
        
            
添加学生信息
            
                            
            
                            
            
                            
            
                            
            
                            
                        返回        
    

<%@ 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"%>    
  
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    

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

<%@ 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
    
        <%            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("https://blog.csdn.net/weixin_52849365/article/details/register.jsp").forward(request, response);        }    }}

③ 分页查询表示层 (https://blog.csdn.net/weixin_52849365/article/details/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("/https://blog.csdn.net/weixin_52849365/article/details/ShowStudentsByPageServlet")public class https://blog.csdn.net/weixin_52849365/article/details/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 (https://blog.csdn.net/weixin_52849365/article/details/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("/https://blog.csdn.net/weixin_52849365/article/details/ShowAllStudentsServlet")public class https://blog.csdn.net/weixin_52849365/article/details/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("https://blog.csdn.net/weixin_52849365/article/details/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("https://blog.csdn.net/weixin_52849365/article/details/ShowAllStudentsServlet").forward(request, resp);    }}

⑨ 退出登录表示层 (https://blog.csdn.net/weixin_52849365/article/details/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("/https://blog.csdn.net/weixin_52849365/article/details/QuitServlet")public class https://blog.csdn.net/weixin_52849365/article/details/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;    }}

来源地址：https://blog.csdn.net/weixin_52849365/article/details/127349023