登录功能：

@RequestMapping("/")
    public String index(){
        return "login";
    }
    @PostMapping("/login")
    public String login(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        Model model,
                        HttpSession session){
        User user1 = userMapper.selectOne(new QueryWrapper<User>().eq("username",username)
                .eq("password",password));
        if(ObjectUtils.isEmpty(user1)){
            model.addAttribute("msg","账号或密码错误");
            return "login";
        }else {
            session.setAttribute("loginUser",username);
            return "redirect:/list";
        }
    }

前端页面

<tr>
                        <td valign="middle" align="right">
                            用户名:
                        </td>
                        <td valign="middle" align="left">
                            <input type="text" class="inputgri" name="username"/>
                        </td>
                    </tr>
                    <tr>
                        <td valign="middle" align="right">
                            密码:
                        </td>
                        <td valign="middle" align="left">
                            <input type="password" class="inputgri" name="password"/>
                        </td>
                    </tr>
                    <tr>
                        <p style="color: red" th:text="${msg}"></p>
                    </tr>

注册功能：

@RequestMapping("/zhuce")
    public String zhuce(){
        return "regist";
    }
    @PostMapping("/register")
    public String register(User user,String code,HttpSession session){
        String code1 = (String)session.getAttribute("code");
        if(code1.equalsIgnoreCase(code)){
            userMapper.insert(user);
            return "redirect:/";
        }else{
            return "redirect:/zhuce";
        }

    }

查找功能

@GetMapping("/list")
    public String list(Model model){
        List<Student> studentList = studentMapper.selectList(null);
        model.addAttribute("studentlist",studentList);
        return "emplist";
    }

前端页面

<tr class="row1" th:each="std:${studentlist}">
                    <td>
                        <span th:text="${std.getSid()}"></span>
                    </td>
                    <td>
                        <span th:text="${std.getSname()}"></span>
                    </td>
                    <td>
                        <span th:text="${std.getGender()}"></span>
                    </td>
                    <td>
                        <!--日期格式化-->
                        <span th:text="${#dates.format(std.getBirthday(),'yyyy-MM-dd')}"></span>
                    </td>
                    <td>
                        <span th:text="${std.getAddress()}"></span>
                    </td>
                    <td>
                        <span th:text="${std.getClassesId()}"></span>
                    </td>
                    <td>
                        <a th:href="@{/delete(sid=${std.sid})}">删除信息</a>&nbsp;
                        <a th:href="@{/update(sid=${std.sid})}">修改信息</a>
                    </td>
                </tr>

添加功能

@GetMapping("/add")
    public String add(){
        return "addEmp";
    }
    @PostMapping("/save")
    public String save(Student student){
        studentMapper.insert(student);
        return "redirect:/list";
    }

前端页面（部分）

<tr>
                        <td valign="middle" align="right">
                            姓名:
                        </td>
                        <td valign="middle" align="left">
                            <input type="text" class="inputgri" name="sname"/>
                        </td>
                    </tr>

                    <tr>
                        <td valign="middle" align="right">
                            性别:
                        </td>
                        <td valign="middle" align="left">
                            <input type="radio" class="inputgri" name="gender" value="男"/><label>男</label>
                            <input type="radio" class="inputgri" name="gender" value="女"/><label>女</label>
                        </td>
                    </tr>

删除功能

@GetMapping("/delete")
    public String delete(int sid){
        studentMapper.deleteById(sid);
        return "redirect:/list";
    }

前端页面

<td>
                        <a th:href="@{/delete(sid=${std.sid})}">删除信息</a>&nbsp;
                        <a th:href="@{/update(sid=${std.sid})}">修改信息</a>
                    </td>

修改功能

@GetMapping("/update")
    public String update(int sid,Model model){
        Student student = studentMapper.selectById(sid);
        model.addAttribute("emp",student);
        return "updateEmp";
    }
    @PostMapping("/update2")
    public String update2(Student student){
        studentMapper.updateById(student);
        return "redirect:/list";
    }

前端页面（部分）

<tr>
                        <td valign="middle" align="right">
                            性别:
                        </td>
                        <td valign="middle" align="left">
                            <input type="radio" class="inputgri" name="gender" th:checked="${emp.gender=='男'}" value="男"/><label>男</label>
                            <input type="radio" class="inputgri" name="gender" th:checked="${emp.gender=='女'}" value="女"/><label>女</label>
                        </td>
                    </tr>
                    <tr>
                        <td valign="middle" align="right">
                            生日:
                        </td>
                        <td valign="middle" align="left">
                            <input type="text" class="inputgri" name="birthday"
                                   th:value="${#dates.format(emp.birthday,'yyyy/MM/dd')}"/>
                        </td>
                    </tr>

安全退出功能

 @RequestMapping("/logout")
    public String logout(HttpSession session){
        session.invalidate();
        return "redirect:/";
    }

前端

<a class="nav-link" th:href="@{/logout}">安全退出</a>

list页面显示username

<h1>
                Welcome![[${session.loginUser}]]
            </h1>