学习java的日子 Day64 学生管理系统 web2.0 web版本

MVC设计模式

概念 - 代码的分层

MVC：项目分层的思想

字母	表示	层	理解
M	Modle	模型层	业务的具体实现
V	View	视图层	展示数据
C	Controller	控制器层	控制业务流程（跳转）

1.细化理解层数

Controller：控制器层，用于存放Servlet（页面跳转）

View：视图层，用于存放前端页面（jsp）

Modle-Biz/service：逻辑业务层，用于存放业务具体的实现

Modle-Dao/mapper：数据持久层，用于存放操作数据的实现（数据的增删改查）

MVC涉及到了前端，而后端只涉及到了MC

1.1 优缺点

缺点：使用MVC不能减少代码量， 还会增加系统结构和实现的复杂性

优点：整个项目结构清晰，业务逻辑清晰，降低了代码的耦合性，代码的重用性高

注意：一般来说，使用设计模式都会增加代码量

1.2 各层的命名规范

Controller控制器层：controller/servlet/action/web

Modle-Biz 逻辑业务层：service/biz

Modle-Dao 数据持久层：dao/persist/mapper

2.学生管理系统 web2.0 mvc版本

具体的业务逻辑详情请见 Day59 学生管理系统 web1.0（直接使用servlet+jsp写的），v2.0只是使用mvc分层思想进行构造

项目结构：(总结里有展示所有层)

注意：mapper层、service层、controller层

2.1 学生 student

StudentMapper

通过具体的业务，判断需要用到什么增删查改，然后写数据库增删查改的接口，让实现类去实现

public interface StudentMapper {//添加学生public void add(String username,String password,String name,String sex,int age,String hobbies,String photo);//删除学生，通过usernamepublic void delete(String username);//更新学生的密码，通过username和newPasswordpublic void update(String username,String newPassword);//更新学生信息(除了密码)，通过username去操作，没有更新照片public void update(String username,String name,String sex,int age,String hobbies);//更新学生信息(除了密码)，通过username更新，有更新照片public void update(String username,String name,String sex,int age,String hobbies,String photo);//获取学生信息，通过usernamepublic Student getStudent(String username);//获取学生信息，通过username和usernamepublic Student getStudent(String username,String password);//获取学生的所有集合信息，用于分页，offset--偏移量，count--数据条数public List<Student> getStudents(int offset,int count);//获取当前表的总条数public int getAllCount();
}

StudentMapperImpl

具体操作数据库的增删查改，可以使用自己写的DBUtils 工具类

public class StudentMapperImpl implements StudentMapper {@Overridepublic void add(String username, String password, String name, String sex, int age, String hobbies, String photo) {try {DBUtils.commonUpdate("insert into student(username,password,name,sex,age,hobbies,photo) values(?,?,?,?,?,?,?)",username,password,name,sex,age, hobbies,photo);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void delete(String username) {try {DBUtils.commonUpdate("delete from student where username = ?",username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String newPassword) {try {DBUtils.commonUpdate("update student set password=? where username=?",newPassword,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String name, String sex, int age, String hobbies) {try {DBUtils.commonUpdate("update student set name=?,sex=?,age=?,hobbies=? where username=?",name,sex,age,hobbies,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String name, String sex, int age, String hobbies, String photo) {try {DBUtils.commonUpdate("update student set name=?,sex=?,age=?,hobbies=?,photo=? where username=?",name,sex,age,hobbies,photo,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic Student getStudent(String username) {Student student = null;try {student = DBUtils.commonQueryObj(Student.class, "select * from student where username = ?", username);} catch (SQLException e) {throw new RuntimeException(e);}return student;}@Overridepublic Student getStudent(String username, String password) {Student student = null;try {student = DBUtils.commonQueryObj(Student.class, "select * from student where username = ? and password = ?", username, password);} catch (SQLException e) {throw new RuntimeException(e);}return student;}@Overridepublic List<Student> getStudents(int offset, int count) {List<Student> students = null;try {students = DBUtils.commonQueryList(Student.class, "select * from student limit ?,?", offset, count);} catch (SQLException e) {throw new RuntimeException(e);}return students;}@Overridepublic int getAllCount() {int allcount = 0;try {allcount = DBUtils.getAllCount("student");} catch (SQLException e) {throw new RuntimeException(e);}return allcount;}
}

service业务逻辑层

具体的业务流程，存放Servlet

不用进行跳转，在Controller层进行跳转

有返回值的返回true/false就可以了

StudentService

public interface StudentService {//是否成功注册功能public boolean isRegister(String username);//注册功能public boolean register(HttpServletRequest request, HttpServletResponse response);//初始化学生信息功能public void initModify(HttpServletRequest request, HttpServletResponse response);//修改学生信息功能public void modify(HttpServletRequest request, HttpServletResponse response);//获取学生信息列表，方便分页public void getStudents(HttpServletRequest request, HttpServletResponse response);//删除学生功能public void delete(HttpServletRequest request, HttpServletResponse response);//添加学生的功能public boolean add(HttpServletRequest request, HttpServletResponse response);
}

StudentServiceImpl

实现 StudentService接口，写具体的业务逻辑

public class StudentServiceImpl implements StudentService {private StudentMapper studentMapper = new StudentMapperImpl();//是否成功注册功能@Overridepublic boolean isRegister(String username) {Student student = studentMapper.getStudent(username);if(student == null){//允许注册return true;}return false;}//注册功能（注册表单是二进制流，涉及到了图片上传）@Overridepublic boolean register(HttpServletRequest request, HttpServletResponse response) {ParseRequestData<Student> parseRequestData = ParseRequestDataUtils.parseRequest(request, Student.class, "upload\\student");Student stu = parseRequestData.getT();InputStream in = parseRequestData.getIn();OutputStream out = parseRequestData.getOut();boolean register = isRegister(stu.getUsername());if(register){//将数据插入到学生表中studentMapper.add(stu.getUsername(),stu.getPassword(),stu.getName(),stu.getSex(),stu.getAge(),stu.getHobbies(),stu.getPhoto());//将头像存储到本地磁盘try {IOUtils.copy(in,out);in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}return true;}else{try {in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}request.setAttribute("msg","注册失败 -- 账号已注册");return false;}}//初始化学生信息功能@Overridepublic void initModify(HttpServletRequest request, HttpServletResponse response) {String username = request.getParameter("username");Student student = studentMapper.getStudent(username);request.setAttribute("student",student);}//修改学生信息功能@Overridepublic void modify(HttpServletRequest request, HttpServletResponse response) {ParseRequestData<Student> parseRequestData = ParseRequestDataUtils.parseRequest(request, Student.class, "upload\\student");Student stu = parseRequestData.getT();InputStream in = parseRequestData.getIn();OutputStream out = parseRequestData.getOut();try {if(stu.getPhoto() != null){//说明用户修改头像studentMapper.update(stu.getUsername(),stu.getName(), stu.getSex(), stu.getAge(),stu.getHobbies(),stu.getPhoto());IOUtils.copy(in,out);//文件复制}else{studentMapper.update(stu.getUsername(),stu.getName(), stu.getSex(), stu.getAge(),stu.getHobbies());}if(in != null){in.close();}if(out != null){out.close();}} catch (IOException e) {throw new RuntimeException(e);}String role = (String) request.getSession().getAttribute("role");if("student".equals(role)){//更新Session里的数据request.getSession().setAttribute("name",stu.getName());//更新Cookie里的数据response.addCookie(CookieUtils.createCookie("name",stu.getName(),60*60*24*5));if(stu.getPhoto() != null){request.getSession().setAttribute("photo",stu.getPhoto());response.addCookie(CookieUtils.createCookie("photo",stu.getPhoto(),60*60*24*5));}}}//获取学生信息列表，方便分页@Overridepublic void getStudents(HttpServletRequest request, HttpServletResponse response) {//获取当前页数int curPage = Integer.parseInt(request.getParameter("curPage"));//设置URLString url = "student?action=doGetStudents&curPage=";//设置当前页的数据条数int count = 15;//计算偏移量int offset = (curPage-1)*count;//计算总页数int allCount = studentMapper.getAllCount();int totalPage = PageUtils.getTotalPage(allCount,count);//从数据库获取学生的集合List<Student> students = studentMapper.getStudents(offset,count);//处理学生集合List<StudentDto> studentDtos = DtoUtils.studentDtoListHandler(students);//封装Page对象Page<StudentDto> page = new Page<>(url, curPage, totalPage, studentDtos);//将数据存入到请求对象中request.setAttribute("page",page);}//删除学生功能@Overridepublic void delete(HttpServletRequest request, HttpServletResponse response) {String username = request.getParameter("username");studentMapper.delete(username);}//添加学生的功能@Overridepublic boolean add(HttpServletRequest request, HttpServletResponse response) {ParseRequestData<Student> parseRequestData = ParseRequestDataUtils.parseRequest(request, Student.class, "upload\\student");Student stu = parseRequestData.getT();InputStream in = parseRequestData.getIn();OutputStream out = parseRequestData.getOut();boolean register = isRegister(stu.getUsername());if(register){//将数据插入到学生表中studentMapper.add(stu.getUsername(),stu.getPassword(),stu.getName(),stu.getSex(),stu.getAge(),stu.getHobbies(),stu.getPhoto());//将头像存储到本地磁盘try {IOUtils.copy(in,out);in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}return true;}else{try {in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}request.setAttribute("msg","添加失败 -- 账号已添加");return false;}}}

ParseRequestDataUtils

package com.qf.utils;public class ParseRequestDataUtils {public static <T> ParseRequestData parseRequest(HttpServletRequest request,Class<T> clazz,String path){ParseRequestData<T> parseRequestData = new ParseRequestData<>();//创建文件上传工厂类的对象DiskFileItemFactory factory = new DiskFileItemFactory();//创建文件上传类的对象ServletFileUpload upload = new ServletFileUpload(factory);HashMap<String, String> map = new HashMap<>();try {//解析请求List<FileItem> list = upload.parseRequest(request);for (FileItem fileItem : list) {if(fileItem.isFormField()){//文本数据String name = fileItem.getFieldName();String value = fileItem.getString("UTF-8");String v = map.get(name);if(v == null){//说明是第一次添加map.put(name,value);}else{//不是第一次添加就需要拼接（多选框的情况）map.put(name,v + "," + value);}}else{//二进制数据//D:\\apache-tomcat-8.0.49\\webapps\\Day23_upload_war_exploded\\upload\\student//D:\\apache-tomcat-8.0.49\\webapps\\Day23_upload_war_exploded\\upload\\teacherString realPath = request.getServletContext().getRealPath(path);//文件存储目录 -- 自定义路径\\用户名realPath = realPath + File.separator + map.get("username");File file = new File(realPath);if(!file.exists()){file.mkdirs();}String fileName = fileItem.getName();//获取文件名//自定义路径\\用户名\\tx01.jpgrealPath = realPath + File.separator + fileName;//拼接路径InputStream in = fileItem.getInputStream();if(in.available() != 0){FileOutputStream out = new FileOutputStream(realPath);parseRequestData.setIn(in);parseRequestData.setOut(out);map.put("photo",path + File.separator + map.get("username") + File.separator + fileName);}}}} catch (FileUploadException e) {throw new RuntimeException(e);} catch (FileNotFoundException e) {throw new RuntimeException(e);} catch (IOException e) {throw new RuntimeException(e);}Set<Map.Entry<String, String>> entries = map.entrySet();for (Map.Entry<String, String> entry : entries) {System.out.println(entry);}T t = null;try {t = clazz.newInstance();//将map中的数据映射到实体类对象中BeanUtils.populate(t,map);} catch (IllegalAccessException e) {throw new RuntimeException(e);} catch (InvocationTargetException e) {throw new RuntimeException(e);} catch (InstantiationException e) {throw new RuntimeException(e);}parseRequestData.setT(t);return parseRequestData;}
}

controller

根据每一个前端传过来的action功能来判断跳转

判断功能进行页面跳转

action=“student?action=doRegister”，前端设置路径加上action=xxx功能

Controller进行具体的判断，成功就重定向，失败就转发

@WebServlet("/student")
public class StudentController extends BaseServlet {private StudentService studentService = new StudentServiceImpl();//注册功能public void doRegister(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {boolean register = studentService.register(request, response);if(register){response.sendRedirect("login.jsp");}else{request.getRequestDispatcher("register.jsp").forward(request,response);}}//初始化修改功能public void doInitModify(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {studentService.initModify(request,response);request.getRequestDispatcher("stuInfo.jsp").forward(request,response);}//修改功能public void doModify(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {studentService.modify(request,response);String role = (String) request.getSession().getAttribute("role");if("student".equals(role)){response.sendRedirect("index.jsp");}else if("teacher".equals(role)){request.getRequestDispatcher("student?action=doGetStudents&curPage=1").forward(request,response);}else if("admin".equals(role)){request.getRequestDispatcher("student?action=doGetStudents&curPage=1").forward(request,response);}}//展示数据功能public void doGetStudents(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {studentService.getStudents(request,response);request.getRequestDispatcher("stuList.jsp").forward(request,response);}//删除功能public void doDelete(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {studentService.delete(request,response);request.getRequestDispatcher("student?action=doGetStudents&curPage=1").forward(request,response);}//添加学生功能public void doAddStu(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {boolean register = studentService.register(request, response);if(register){request.getRequestDispatcher("student?action=doGetStudents&curPage=1").forward(request,response);}else{request.getRequestDispatcher("stuAdd.jsp").forward(request,response);}}//是否注册学生的提示功能（ajax）public void isRegister(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String username = request.getParameter("username");boolean register = studentService.isRegister(username);String code;if(register){code="1";}else {code="-1";}response.getWriter().write(code);}
}

BaseServlet

给控制层重写的servlet，以前继承HttpServlet，就会写很多的if-else判断，太麻烦了

package com.qf.servlet;public class BaseServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//url -- http://localhost:8080/Day24_MVC_war_exploded/user?action=doLoginString action = request.getParameter("action");//doLogin//获取Controller类的class对象Class<? extends BaseServlet> clazz = this.getClass();try {//根据action获取Controller类对应的方法对象Method method = clazz.getDeclaredMethod(action, HttpServletRequest.class, HttpServletResponse.class);//设置操作权限method.setAccessible(true);//调用方法method.invoke(this,request,response);} catch (NoSuchMethodException e) {throw new RuntimeException(e);} catch (InvocationTargetException e) {throw new RuntimeException(e);} catch (IllegalAccessException e) {throw new RuntimeException(e);}}
}

2.2 老师 teacher

TeacherMapper

明确数据库的功能

public interface TeacherMapper {//添加老师public void add(String username,String password,String name,String sex,int age,int courseId,String photo);//删除老师，通过usernamepublic void delete(String username);//更新老师的密码，通过username和newPasswordpublic void update(String username,String newPassword);//更新老师信息(除了密码)，通过username去操作，没有更新照片public void update(String username,String name,String sex,int age,int courseId);//更新老师信息(除了密码)，通过username更新，有更新照片public void update(String username,String name,String sex,int age,int courseId,String photo);//获取老师信息，通过usernamepublic Teacher getTeacher(String username);//获取老师信息，通过username和usernamepublic Teacher getTeacher(String username,String password);//获取老师的所有集合信息，用于分页，offset--偏移量，count--数据条数public List<Teacher> getTeachers(int offset,int count);//获取当前表的总条数public int getAllCount();
}

StudentMapperImpl

public class StudentMapperImpl implements StudentMapper {@Overridepublic void add(String username, String password, String name, String sex, int age, String hobbies, String photo) {try {DBUtils.commonUpdate("insert into student(username,password,name,sex,age,hobbies,photo) values(?,?,?,?,?,?,?)",username,password,name,sex,age, hobbies,photo);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void delete(String username) {try {DBUtils.commonUpdate("delete from student where username = ?",username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String newPassword) {try {DBUtils.commonUpdate("update student set password=? where username=?",newPassword,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String name, String sex, int age, String hobbies) {try {DBUtils.commonUpdate("update student set name=?,sex=?,age=?,hobbies=? where username=?",name,sex,age,hobbies,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic void update(String username, String name, String sex, int age, String hobbies, String photo) {try {DBUtils.commonUpdate("update student set name=?,sex=?,age=?,hobbies=?,photo=? where username=?",name,sex,age,hobbies,photo,username);} catch (SQLException e) {throw new RuntimeException(e);}}@Overridepublic Student getStudent(String username) {Student student = null;try {student = DBUtils.commonQueryObj(Student.class, "select * from student where username = ?", username);} catch (SQLException e) {throw new RuntimeException(e);}return student;}@Overridepublic Student getStudent(String username, String password) {Student student = null;try {student = DBUtils.commonQueryObj(Student.class, "select * from student where username = ? and password = ?", username, password);} catch (SQLException e) {throw new RuntimeException(e);}return student;}@Overridepublic List<Student> getStudents(int offset, int count) {List<Student> students = null;try {students = DBUtils.commonQueryList(Student.class, "select * from student limit ?,?", offset, count);} catch (SQLException e) {throw new RuntimeException(e);}return students;}@Overridepublic int getAllCount() {int allcount = 0;try {allcount = DBUtils.getAllCount("student");} catch (SQLException e) {throw new RuntimeException(e);}return allcount;}
}

业务逻辑层

TeacherService

public interface TeacherService {public boolean isAdd(String username);public boolean add(HttpServletRequest request, HttpServletResponse response);public void initModify(HttpServletRequest request, HttpServletResponse response);public void modify(HttpServletRequest request, HttpServletResponse response);public void getTeachers(HttpServletRequest request, HttpServletResponse response);public void delete(HttpServletRequest request, HttpServletResponse response);
}

TeacherServiceImpl

public class TeacherServiceImpl implements TeacherService {private TeacherMapper teacherMapper = new TeacherMapperImpl();private CourseService courseService = new CourseServiceImpl();@Overridepublic boolean isAdd(String username) {Teacher teacher = teacherMapper.getTeacher(username);if(teacher == null){return true;}return false;}@Overridepublic boolean add(HttpServletRequest request, HttpServletResponse response) {ParseRequestData<Teacher> parseRequestData = ParseRequestDataUtils.parseRequest(request, Teacher.class, "upload\\teacher");Teacher t = parseRequestData.getT();InputStream in = parseRequestData.getIn();OutputStream out = parseRequestData.getOut();boolean add = isAdd(t.getUsername());if(add){//将数据插入到老师表中teacherMapper.add(t.getUsername(),t.getPassword(),t.getName(),t.getSex(),t.getAge(),t.getCourseId(),t.getPhoto());//将头像存储到本地磁盘try {IOUtils.copy(in,out);in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}return true;}else{try {in.close();out.close();} catch (IOException e) {throw new RuntimeException(e);}request.setAttribute("msg","添加失败 -- 账号已存在");return false;}}@Overridepublic void initModify(HttpServletRequest request, HttpServletResponse response) {String username = request.getParameter("username");Teacher teacher = teacherMapper.getTeacher(username);request.setAttribute("teacher",teacher);courseService.getCourses(request,response);}@Overridepublic void modify(HttpServletRequest request, HttpServletResponse response) {ParseRequestData<Teacher> parseRequestData = ParseRequestDataUtils.parseRequest(request, Teacher.class, "upload\\teacher");Teacher tea = parseRequestData.getT();InputStream in = parseRequestData.getIn();OutputStream out = parseRequestData.getOut();try {if(tea.getPhoto() != null){//说明用户修改头像teacherMapper.update(tea.getUsername(),tea.getName(), tea.getSex(), tea.getAge(),tea.getCourseId(),tea.getPhoto());IOUtils.copy(in,out);}else{teacherMapper.update(tea.getUsername(),tea.getName(), tea.getSex(), tea.getAge(),tea.getCourseId());}if(in != null){in.close();}if(out != null){out.close();}} catch (IOException e) {throw new RuntimeException(e);}String role = (String) request.getSession().getAttribute("role");if("teacher".equals(role)){//更新Session里的数据request.getSession().setAttribute("name",tea.getName());//更新Cookie里的数据response.addCookie(CookieUtils.createCookie("name",tea.getName(),60*60*24*5));if (tea.getPhoto() != null){request.getSession().setAttribute("photo",tea.getPhoto());response.addCookie(CookieUtils.createCookie("photo",tea.getPhoto(),60*60*24*5));}}}@Overridepublic void getTeachers(HttpServletRequest request, HttpServletResponse response) {//获取当前页数int curPage = Integer.parseInt(request.getParameter("curPage"));//设置URLString url = "teacher?action=doGetTeachers&curPage=";//设置当前页的数据条数int count = 15;//计算偏移量int offset = (curPage-1)*count;//计算总页数int allCount = teacherMapper.getAllCount();int totalPage = PageUtils.getTotalPage(allCount,count);//从数据库获取老师的集合List<Teacher> teachers = teacherMapper.getTeachers(offset,count);//处理老师集合List<TeacherDto> teacherDtos = DtoUtils.teacherDtoListHandler(teachers);//封装Page对象Page<TeacherDto> page = new Page<>(url, curPage, totalPage, teacherDtos);//将数据存入到请求对象中request.setAttribute("page",page);}@Overridepublic void delete(HttpServletRequest request, HttpServletResponse response) {String username = request.getParameter("username");teacherMapper.delete(username);}
}

控制器层

TeacherController

@WebServlet("/teacher")
public class TeacherController extends BaseServlet {private TeacherService teacherService = new TeacherServiceImpl();public void doInitModify(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {teacherService.initModify(request,response);request.getRequestDispatcher("teaInfo.jsp").forward(request,response);}public void doModify(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException {teacherService.modify(request,response);request.getRequestDispatcher("teacher?action=doGetTeachers&curPage=1").forward(request,response);}public void doGetTeachers(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException {teacherService.getTeachers(request,response);request.getRequestDispatcher("TeaList.jsp").forward(request,response);}public void doDelete(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {teacherService.delete(request,response);request.getRequestDispatcher("teacher?action=doGetTeachers&curPage=1").forward(request,response);}public void doAddTea(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {boolean add = teacherService.add(request,response);if(add){request.getRequestDispatcher("teacher?action=doGetTeachers&curPage=1").forward(request,response);}else{request.getRequestDispatcher("teaAdd.jsp").forward(request,response);}}}

2.3 用户 user

user是学生和老师的父类，两个都有的功能就写在user里

注意：在数据库中没有user这个表，这是把学生和老师相同的功能提出来了，放在user里

UserService

public interface UserService {//绘制验证码功能public void drawCode(HttpServletRequest request, HttpServletResponse response);//登录功能public boolean login(HttpServletRequest request, HttpServletResponse response);//记住我功能public void rememberMe(HttpServletResponse response,String username,String name,String role,String photo);//安全退出功能public void loginOut(HttpServletRequest request, HttpServletResponse response);//修改验证码功能public boolean resetPassword(HttpServletRequest request, HttpServletResponse response);}

UserServiceImpl

public class UserServiceImpl implements UserService {private StudentMapper studentMapper = new StudentMapperImpl();private TeacherMapper teacherMapper = new TeacherMapperImpl();private AdminMapper adminMapper=  new AdminMapperImpl();//绘制验证码功能@Overridepublic void drawCode(HttpServletRequest request, HttpServletResponse response) {//设置宽高的变量int width = 120;int height = 30;//创建画布BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);//获取画笔Graphics graphics = image.getGraphics();//设置背景色 -- 填充矩形graphics.setColor(Color.BLUE);graphics.fillRect(0,0,width,height);//设置验证码Random random = new Random();String[] codes = {"A","B","C","D","E","F","G","H","J","K","M","N","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9"};Color[] colors = {Color.CYAN,Color.BLACK,Color.GREEN,Color.PINK,Color.WHITE,Color.RED,Color.ORANGE};StringBuffer sb = new StringBuffer();for (int i = 0; i < 4; i++) {String randomCode = codes[random.nextInt(codes.length)];Color randomColor = colors[random.nextInt(colors.length)];graphics.setColor(randomColor);//设置随机颜色graphics.setFont(new Font("宋体",Font.BOLD,20+random.nextInt(10)));//设置字体（字体,样式,大小）graphics.drawString(randomCode,20+i*25,15+random.nextInt(10));//设置单个验证码sb.append(randomCode);}//将系统验证码设置到Session对象中(会话对象)HttpSession session = request.getSession();//获取请求里的JSESSIONID(客户端Cookie里的数据)，如果没有就创建Session对象，如果有就从Session容器中获取会话对象session.setAttribute("sysCode",sb.toString());//设置干扰线graphics.setColor(Color.YELLOW);for (int i = 0; i < 3; i++) {graphics.drawLine(random.nextInt(width),random.nextInt(height),random.nextInt(width),random.nextInt(height));//绘制直线(x1,y1,x2,y2) -> 两点为一线}//将画布以jpg形式的文件传出给客户端try {ImageIO.write(image,"jpg",response.getOutputStream());} catch (IOException e) {throw new RuntimeException(e);}}//登录功能@Overridepublic boolean login(HttpServletRequest request, HttpServletResponse response) {//获取请求中的数据String username = request.getParameter("username");String password = request.getParameter("password");String userCode = request.getParameter("userCode");String rememberMe = request.getParameter("rememberMe");String role = request.getParameter("role");//从Session对象中获取系统的验证码String sysCode = (String) request.getSession().getAttribute("sysCode");if(sysCode.equalsIgnoreCase(userCode)){//验证码正确User user = null;if("student".equals(role)){user = studentMapper.getStudent(username,password);}else if("teacher".equals(role)){user = teacherMapper.getTeacher(username,password);} else if ("admin".equals(role)) {user = adminMapper.getAdmin(username, password);}if(user != null){//登录成功//判断是否记住我if(rememberMe != null){if("admin".equals(role)){rememberMe(response,user.getUsername(),user.getPassword(),role);HttpSession session = request.getSession();session.setAttribute("username",user.getUsername());session.setAttribute("password",user.getPassword());session.setAttribute("role",role);return true;}else if ("student".equals(role) || "teacher".equals(role)){rememberMe(response,user.getUsername(),user.getName() ,role,user.getPhoto());//将数据存储到Session中HttpSession session = request.getSession();session.setAttribute("username",user.getUsername());session.setAttribute("name",user.getName());session.setAttribute("role",role);session.setAttribute("photo",user.getPhoto());return true;}}if("admin".equals(role)){HttpSession session = request.getSession();session.setAttribute("username",user.getUsername());session.setAttribute("name",user.getPassword());session.setAttribute("role",role);}else if ("student".equals(role) || "teacher".equals(role)){//将数据存储到Session中HttpSession session = request.getSession();session.setAttribute("username",user.getUsername());session.setAttribute("name",user.getName());session.setAttribute("role",role);session.setAttribute("photo",user.getPhoto());}return true;}else{//登录失败 -- 账号或密码错误request.setAttribute("msg","登录失败 -- 账号或密码错误");return false;}}else{//登录失败 - 验证码错误request.setAttribute("msg","登录失败 -- 验证码错误");return false;}}//管理员的记住我private void rememberMe(HttpServletResponse response, String username, String password, String role) {response.addCookie(CookieUtils.createCookie("username",username,60*60*24*5));response.addCookie(CookieUtils.createCookie("password",password,60*60*24*5));response.addCookie(CookieUtils.createCookie("role",role,60*60*24*5));}//记住我功能@Overridepublic void rememberMe(HttpServletResponse response,String username, String name, String role, String photo) {//将凭证添加到Cookie中response.addCookie(CookieUtils.createCookie("username",username,60*60*24*5));response.addCookie(CookieUtils.createCookie("name",name,60*60*24*5));response.addCookie(CookieUtils.createCookie("role",role,60*60*24*5));response.addCookie(CookieUtils.createCookie("photo",photo,60*60*24*5));}//安全退出功能@Overridepublic void loginOut(HttpServletRequest request, HttpServletResponse response) {//删除Cookie里的数据response.addCookie(CookieUtils.createCookie("username","",0));response.addCookie(CookieUtils.createCookie("name","",0));response.addCookie(CookieUtils.createCookie("role","",0));response.addCookie(CookieUtils.createCookie("photo","",0));response.addCookie(CookieUtils.createCookie("password","",0));//删除Session里的数据HttpSession session = request.getSession();session.removeAttribute("username");session.removeAttribute("name");session.removeAttribute("role");session.removeAttribute("photo");session.removeAttribute("password");}//修改密码功能@Overridepublic boolean resetPassword(HttpServletRequest request, HttpServletResponse response) {//获取请求中的数据String username = request.getParameter("username");String password = request.getParameter("password");String newPassword = request.getParameter("newPassword");String role = request.getParameter("role");User user = null;if("student".equals(role)){user = studentMapper.getStudent(username,password);}else if("teacher".equals(role)){user = teacherMapper.getTeacher(username,password);} else if ("admin".equals(role)) {user = adminMapper.getAdmin(username, password);}if(user != null){if("student".equals(role)){studentMapper.update(username,newPassword);}else if("teacher".equals(role)){teacherMapper.update(username,newPassword);} else if ("admin".equals(role)) {adminMapper.update(username,newPassword);}return true;}else{request.setAttribute("msg","修改密码失败 -- 原密码不正确");return false;}}
}

UserController

，前端传过来的路径中带有action=“xxx功能”，然后进行xxx功能的相关业务的跳转

@WebServlet("/user")
public class UserController extends BaseServlet {private UserService userService = new UserServiceImpl();public void doDrawCode(HttpServletRequest request,HttpServletResponse response){userService.drawCode(request,response);}public void doLogin(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException {boolean login = userService.login(request, response);if(login){response.sendRedirect("index.jsp");}else{request.getRequestDispatcher("login.jsp").forward(request,response);}}public void doLoginOut(HttpServletRequest request,HttpServletResponse response) throws IOException {userService.loginOut(request, response);response.sendRedirect("welcome.html");}public void doResetPassword(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {boolean resetPassword = userService.resetPassword(request, response);if(resetPassword){request.getRequestDispatcher("user?action=doLoginOut").forward(request,response);}else{request.getRequestDispatcher("resetPassword.jsp").forward(request,response);}}}

2.4 管理员

功能：

1.登录（user里有）

2.修改密码（user里有）

3.管理老师 – 老师列表页面（分页、修改、删除、添加）

4.管理学科 – 学科列表页面（展示所有学科、修改、删除、添加）

5.管理学生 – 学生列表页面（分页、修改、删除、添加）

实体类 Admin 直接继承user类

SQL – admin ：username、password

public class Admin extends User{}

AdminMapper

public interface AdminMapper {//获取管理员信息，通过usernamepublic Admin getAdmin(String username);//获取管理员信息，通过username和usernamepublic Admin getAdmin(String username,String password);//更新管理员的密码，通过username和newPasswordpublic void update(String username,String newPassword);
}

AdminMapperImpl

public class AdminMapperImpl implements AdminMapper {@Overridepublic Admin getAdmin(String username) {Admin admin=null;try {admin = DBUtils.commonQueryObj(Admin.class, "select * from admin where username =?", username);} catch (SQLException e) {throw new RuntimeException(e);}return admin;}@Overridepublic Admin getAdmin(String username, String password) {Admin admin=null;try {admin = DBUtils.commonQueryObj(Admin.class, "select * from admin where username =? and password=?", username,password);} catch (SQLException e) {throw new RuntimeException(e);}return admin;}@Overridepublic void update(String username, String newPassword) {try {DBUtils.commonUpdate("update admin set password = ? where username =?", newPassword, username);} catch (SQLException e) {throw new RuntimeException(e);}}
}

AdminService

都是uer里写了的，就没有AdminServiceImpl,controller层也没有，直接在index.jsp跳转就可以了

public interface AdminService {//登录功能public boolean login(HttpServletRequest request, HttpServletResponse response);//修改验证码功能public boolean resetPassword(HttpServletRequest request, HttpServletResponse response);
}

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head><title>Title</title>
</head>
<body><button οnclick="safeExit()">安全退出</button><h1>详情页面</h1><c:if test="${role eq 'admin'}"><h1>欢迎管理员进入到学生管理系统</h1></c:if><c:if test="${role eq 'student' || role eq 'teacher'}"><h1>欢迎${name}${(role eq "student")?"学员":""}${(role eq "teacher")?"老师":""}进入到学生管理系统</h1><img src="${photo}" width="100px" height="100px"><br/></c:if><a href="resetPassword.jsp">修改密码</a><c:if test="${role eq 'admin'}"><a href="student?action=doGetStudents&curPage=1">管理学生</a><a href="teacher?action=doGetTeachers&curPage=1">管理老师</a><a href="course?action=doGetCourses">管理学科</a></c:if><c:if test="${role eq 'student'}"><a href="student?action=doInitModify&username=${username}">修改信息</a></c:if><c:if test="${role eq 'teacher'}"><a href="teacher?action=doInitModify&username=${username}">修改信息</a><a href="student?action=doGetStudents&curPage=1">查看所有学生</a></c:if><script type="text/javascript">function safeExit(){window.location = "user?action=doLoginOut";}</script>
</body>
</html>

2.5 其他补充

数据库工具类DBUtils

package com.qf.utils;public class DBUtils {private static DruidDataSource pool;private static ThreadLocal<Connection> local;static{Properties properties = new Properties();try {properties.load(DBUtils.class.getClassLoader().getResourceAsStream("DBConfig.properties"));} catch (IOException e) {throw new RuntimeException(e);}String driverClassName = properties.getProperty("driverClassName");String url = properties.getProperty("url");String username = properties.getProperty("username");String password = properties.getProperty("password");int maxActive = Integer.parseInt(properties.getProperty("maxActive"));//初始化数据库连接池pool = new DruidDataSource();//设置参数pool.setDriverClassName(driverClassName);pool.setUrl(url);pool.setUsername(username);pool.setPassword(password);pool.setMaxActive(maxActive);local = new ThreadLocal<>();}/*** 获取连接对象*/public static Connection getConnection() throws SQLException {Connection connection = local.get();//获取当前线程的Connection对象if(connection == null){connection = pool.getConnection();//获取数据库连接池里的连接对象local.set(connection);//将Connection对象添加到local中}return connection;}/*** 关闭资源*/public static void close(Connection connection, Statement statement, ResultSet resultSet){if(resultSet != null){try {resultSet.close();} catch (SQLException e) {throw new RuntimeException(e);}}if(statement != null){try {statement.close();} catch (SQLException e) {throw new RuntimeException(e);}}if(connection != null){try {if(connection.getAutoCommit()){connection.close();local.set(null);}} catch (SQLException e) {throw new RuntimeException(e);}}}/*** 开启事务*/public static void startTransaction() throws SQLException {Connection connection = getConnection();connection.setAutoCommit(false);}/*** 提交事务*/public static void commit() throws SQLException {Connection connection = local.get();if(connection != null){connection.commit();connection.close();local.set(null);}}public static void rollback() throws SQLException {Connection connection = local.get();if(connection != null){connection.rollback();connection.close();local.set(null);}}/*** 更新数据（添加、删除、修改）*/public static int commonUpdate(String sql,Object... params) throws SQLException {Connection connection = null;PreparedStatement statement = null;try {connection = getConnection();statement = connection.prepareStatement(sql);paramHandler(statement,params);int num = statement.executeUpdate();return num;}finally {close(connection,statement,null);}}/*** 添加数据 - 主键回填(主键是int类型可以返回)*/public static int commonInsert(String sql,Object... params) throws SQLException {Connection connection = null;PreparedStatement statement = null;ResultSet resultSet = null;try {connection = getConnection();statement = connection.prepareStatement(sql,PreparedStatement.RETURN_GENERATED_KEYS);paramHandler(statement,params);statement.executeUpdate();resultSet = statement.getGeneratedKeys();int primaryKey = 0;if(resultSet.next()){primaryKey = resultSet.getInt(1);}return primaryKey;}finally {close(connection,statement,resultSet);}}/*** 查询多个数据*/public static <T> List<T> commonQueryList(Class<T> clazz,String sql, Object... params) throws SQLException{Connection connection = null;PreparedStatement statement = null;ResultSet resultSet = null;try {connection = getConnection();statement = connection.prepareStatement(sql);paramHandler(statement,params);resultSet = statement.executeQuery();//获取表数据对象ResultSetMetaData metaData = resultSet.getMetaData();//获取字段个数int count = metaData.getColumnCount();List<T> list = new ArrayList<>();while(resultSet.next()){T t = null;try {t = clazz.newInstance();} catch (InstantiationException e) {throw new RuntimeException(e);} catch (IllegalAccessException e) {throw new RuntimeException(e);}//获取字段名及数据for (int i = 1; i <= count; i++) {String fieldName = metaData.getColumnName(i);Object fieldVal = resultSet.getObject(fieldName);setField(t,fieldName,fieldVal);}list.add(t);}return list;} finally {DBUtils.close(connection,statement,resultSet);}}/*** 查询单个数据*/public static <T> T commonQueryObj(Class<T> clazz,String sql, Object... params) throws SQLException{Connection connection = null;PreparedStatement statement = null;ResultSet resultSet = null;try {connection = getConnection();statement = connection.prepareStatement(sql);paramHandler(statement,params);resultSet = statement.executeQuery();//获取表数据对象ResultSetMetaData metaData = resultSet.getMetaData();//获取字段个数int count = metaData.getColumnCount();if(resultSet.next()){T t = null;try {t = clazz.newInstance();} catch (InstantiationException e) {throw new RuntimeException(e);} catch (IllegalAccessException e) {throw new RuntimeException(e);}//获取字段名及数据for (int i = 1; i <= count; i++) {String fieldName = metaData.getColumnName(i);Object fieldVal = resultSet.getObject(fieldName);setField(t,fieldName,fieldVal);}return t;}} finally {DBUtils.close(connection,statement,resultSet);}return null;}/*** 获取当前表的总条数*/public static int getAllCount(String table) throws SQLException {Connection connection = getConnection();String sql = "select count(1) from " + table;PreparedStatement statement = connection.prepareStatement(sql);ResultSet resultSet = statement.executeQuery();if(resultSet.next()){int allCount = resultSet.getInt(1);return allCount;}return 0;}/*** 处理statement对象参数数据的处理器*/private static void paramHandler(PreparedStatement statement,Object... params) throws SQLException {for (int i = 0; i < params.length; i++) {statement.setObject(i+1,params[i]);}}/*** 获取当前类及其父类的属性对象* @param clazz class对象* @param name 属性名* @return 属性对象*/private static Field getField(Class<?> clazz,String name){for(Class<?> c = clazz;c != null;c = c.getSuperclass()){try {Field field = c.getDeclaredField(name);return field;} catch (NoSuchFieldException e) {} catch (SecurityException e) {}}return null;}/*** 设置对象中的属性* @param obj 对象* @param name 属性名* @param value 属性值*/private static void setField(Object obj,String name,Object value){Field field = getField(obj.getClass(), name);if(field != null){field.setAccessible(true);try {field.set(obj, value);} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}}}

其余代码太多，不一一展示

总结

1…MVC
注意：MVC设计模式和服务端分层思想的区别

2.MVC版本的学生管理系统