功能实现

老师角色查看所有学生

获取学生列表和分页

1.修改index.jsp

不能直接跳stuList.jsp，没数据

    <%if("teacher".equals(role)){%>     ">修改信息     查看所有学生     <%}%> 

2.新增GetStuListServlet

拿数据和分页

@WebServlet("/GetStuListServlet") public class GetStuListServlet extends HttpServlet {      @Override     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {         this.doPost(request, response);     }      @Override     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {         request.setCharacterEncoding("UTF-8");         response.setContentType("text/html;charset=UTF-8");          //获取当前页数         int curPage = Integer.parseInt(request.getParameter("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 totalPage;         try {             int allCount = DBUtils.getAllCount("student");             if(allCount % count == 0){                 totalPage = allCount/count;             }else{                 totalPage = allCount/count + 1;             }         } catch (SQLException e) {             throw new RuntimeException(e);         }          //从数据库获取学生的集合         List students = null;         try {             students = DBUtils.commonQueryList(Student.class, "select * from student limit ?,?", offset, count);         } catch (SQLException e) {             throw new RuntimeException(e);         }          //处理学生集合         List studentDtos = DtoUtils.studentDtoListHandler(students);          //将数据存入到请求对象中         request.setAttribute("curPage",curPage);         request.setAttribute("totalPage",totalPage);         request.setAttribute("studentDtos",studentDtos);         //request.setAttribute("students",students);直接传          //跳转         request.getRequestDispatcher("stuList.jsp").forward(request,response);      } } 

修改DBUtils–分页

新增getAllCount()

    /**      * 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;     } 

修改Student–分页

做假数据，在实体类里面可以写main方法，插入操作

    //做分页的假数据     public static void main(String[] args) {          for (int i = 1; i < 100; i++) {             String username = "xiaohei" + i;             String password = "123123";             String name = "小黑" + i;             String sex = "man";             int age = 23;             String[] hobbies = {"football","basketball"};             try {                 DBUtils.commonUpdate("insert into student(username,password,name,sex,age,hobbies) values(?,?,?,?,?,?)",username,password,name,sex,age, StringUtils.handleArray(hobbies));             } catch (SQLException e) {                 throw new RuntimeException(e);             }         }      } 

新增StudentDto–处理学生信息

分包新增信息处理类，以方便工具类对学生的信息处理

package com.ckl.dto;  import com.ckl.pojo.Student;  public class StudentDto {      private Student student;     private String sex;     private String hobbies;  //自动生成方法略 } 

新增DtoUtils --处理学生信息

工具类，处理学生信息提升页面展示效果

public class DtoUtils {      public static StudentDto studentDtoHandler(Student student){          //处理学生的性别数据         String sex = student.getSex();         if("man".equals(sex)){             sex = "男";         }else if("woman".equals(sex)){             sex = "女";         }          //处理学生的爱好数据         String hobbies = student.getHobbies();         hobbies = hobbies.replaceAll("football","足球");         hobbies = hobbies.replaceAll("basketball","篮球");         hobbies = hobbies.replaceAll("shop","购物");          //创建StudentDto         StudentDto studentDto = new StudentDto(student, sex, hobbies);         return studentDto;     }      public static List studentDtoListHandler(List students){          List studentDtos = new ArrayList<>();          for (Student student : students) {             StudentDto studentDto = studentDtoHandler(student);             studentDtos.add(studentDto);         }         return studentDtos;     }  }  

3.stuList.jsp

直接获取数据库的学生数据

//未处理 List students = (List) request.getAttribute("students");          <%for(Student student:students){%>         <%=student.getUsername()%>         <%=student.getName()%>         <%=student.getSex()%>         <%=student.getAge()%>         <%=student.getHobbies()%> 

添加学生信息处理后获取

//处理后 <%@ page import="java.util.List" %> <%@ page import="com.qf.pojo.Student" %> <%@ page import="com.qf.dto.StudentDto" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %>              <%         List studentDtos = (List) request.getAttribute("studentDtos");         int curPage = (int) request.getAttribute("curPage");         int totalPage = (int) request.getAttribute("totalPage");     %>     返回     
学生列表页面
       //获取学生信息展示         <%for(StudentDto studentDto:studentDtos){%>                      <%}%>     
          
             
账号
             
姓名
             
性别
             
年龄
             
爱好
             
操作
         
                 
<%=studentDto.getStudent().getUsername()%>
                 
<%=studentDto.getStudent().getName()%>
                 
<%=studentDto.getSex()%>
                 
<%=studentDto.getStudent().getAge()%>
                 
<%=studentDto.getHobbies()%>
                 
                     修改                     删除                 
             
 //分页     首页      <%if(curPage > 1){%>         ">上一页     <%}%>     <%if(curPage < totalPage){%>         ">下一页     <%}%>     ">尾页         

老师角色修改和删除学生信息

修改

修改stuList.jsp

         <%for(StudentDto studentDto:studentDtos){%>                                                   ">修改                     ">删除                                       <%}%>  

修改StuModifyServlet

获取角色

通过角色判断修改

学生需要更新Session、Cookie里的数据，跳转详情页面

老师跳转GetStuListServlet，需要更新数据【因为修改了需要刷新页面】

//        request.setAttribute("name",name); //        response.addCookie(CookieUtils.createCookie("name",name,60*60*24*5)); // //        response.sendRedirect("index.jsp");  		String role = (String) request.getSession().getAttribute("role");          if("student".equals(role)){             //更新Session里的数据             request.getSession().setAttribute("name",name);             //更新Cookie里的数据             response.addCookie(CookieUtils.createCookie("name",name,60*60*24*5));             //跳转详情页面             response.sendRedirect("index.jsp");         }else if("teacher".equals(role)){             //跳转             response.sendRedirect("GetStuListServlet?curPage=1");         } 

删除

新增StuDeleteServlet

设置编码格式，获取请求中的账号，通过学生账号删除学生，最后跳转GetStuListServlet同时更新数据

注意：实际开发项目中是不会直接用delete，而是改状态，数据库有提到

@WebServlet("/StuDeleteServlet") public class StuDeleteServlet extends HttpServlet {      @Override     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {         this.doPost(request, response);     }      @Override     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {         request.setCharacterEncoding("UTF-8");         response.setContentType("text/html;charset=UTF-8");          String username = request.getParameter("username");          try {             DBUtils.commonUpdate("delete from student where username=?",username);         } catch (SQLException e) {             throw new RuntimeException(e);         }          //跳转         response.sendRedirect("GetStuListServlet?curPage=1");     } }