SSM02

此时我们已经做好了登录模块接下来可以做一下学生管理系统的增删改查操作

首先，我们应当有一个登录成功后的主界面

在webapp下新建

1.main.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/vue.js"></script>
    <script src="js/jquery.min.js"></script>
    <!-- 引入样式 -->
    <link rel="stylesheet" href="https://unpkg.com/element-ui/lib/theme-chalk/index.css">
    <!-- 引入组件库 -->
    <script src="https://unpkg.com/element-ui/lib/index.js"></script>

    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .el-header {
            background-color: #B3C0D1;
            color: #333;
            line-height: 60px;
        }

        .el-tabs__header {
            margin: 0;
        }

        .el-aside {
            color: #333;
            height: 640px;
        }

        .el-main {
            padding: 0;
        }
    </style>
</head>
<body>
<div id="app">
    <el-container style="height: 500px; border: 1px solid #eee">
        <el-header style="text-align: right; font-size: 12px">
            <span>欢迎用户：</span>
            <el-dropdown>
                <i class="el-icon-setting" style="margin-right: 15px"></i>
                <el-dropdown-menu slot="dropdown">
                    <el-dropdown-item>查看</el-dropdown-item>
                    <el-dropdown-item>新增</el-dropdown-item>
                    <el-dropdown-item>删除</el-dropdown-item>
                </el-dropdown-menu>
            </el-dropdown>
            <span>{{userInfo.ename}}</span>
        </el-header>


        <el-container>
            <el-aside width="200px" style="background-color: rgb(238, 241, 246)">
                <el-menu>
                    <el-submenu v-for="p in permissionArr" :index="p.id">
                        <template slot="title"><i :class="p.icon"></i>{{p.title}}</template>
                        <el-menu-item-group>
                            <el-menu-item v-for="sp in p.subMenu" :index="sp.id"
                                          @click="addTabs(sp)">
                                {{sp.title}}
                            </el-menu-item>
                        </el-menu-item-group>
                    </el-submenu>
                </el-menu>
            </el-aside>

            <el-main>
                <el-tabs v-model="editableTabsValue" type="card" closable @tab-remove="removeTab">
                    <el-tab-pane

                            key="asd"
                            label="欢迎页"
                            name="asd"
                    >
                        <iframe src="http://www.douyu.com" style="border: none;width: 99%;height: 600px;"></iframe>
                    </el-tab-pane>
                    <el-tab-pane
                            v-for="(item, index) in editableTabs"
                            :key="item.id"
                            :label="item.title"
                            :name="item.id"
                    >
                        <iframe :src="item.content" style="border: none;width: 99%;height: 600px;"></iframe>
                    </el-tab-pane>
                </el-tabs>
            </el-main>
        </el-container>
    </el-container>
</div>
<script>
    $.get("/ssm/emp/getInfo", function (backData) {
        app.userInfo = backData.data.userInfo
        app.permissionArr = backData.data.permissionInfo
    })

    var app = new Vue({
        el: "#app",
        data: {
            tableData: [],
            editableTabsValue: "asd",
            editableTabs: [],
            userInfo: {},
            permissionArr: [],
        },
        methods: {
            addTabs(data) {
                if (this.editableTabs.indexOf(data) < 0) {
                    console.log(this.editableTabs)
                    this.editableTabs.push(data);
                }
                this.editableTabsValue = data.id;
            },
            removeTab(targetName) {
                let tabs = this.editableTabs;
                let activeName = this.editableTabsValue;
                if (activeName === targetName) {
                    tabs.forEach((tab, index) => {
                        if (tab.id === targetName) {
                            let nextTab = tabs[index + 1] || tabs[index - 1];
                            if (nextTab) {
                                activeName = nextTab.id;
                            }
                        }
                    });
                }
                this.editableTabsValue = activeName;
                this.editableTabs = tabs.filter(tab => tab.id !== targetName);
            },
        }
    })
</script>
</body>
</html>

在这个页面中，我们点击业务管理中的学生管理，就可以在右侧访问学生管理的界面。其他模块可以自行添加

进入学生管理页面，我们首先要在页面中展示学生信息

先在webapp下新建views/student/list.html

2.list.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../js/vue.js"></script>
    <script src="../../js/jquery.min.js"></script>
    <!-- 引入样式 -->
    <link rel="stylesheet" href="https://unpkg.com/element-ui/lib/theme-chalk/index.css">
    <!-- 引入组件库 -->
    <script src="https://unpkg.com/element-ui/lib/index.js"></script>
</head>
<body>
<div id="app">
    <el-input v-model="queryInfo.name" placeholder="请输入名字" style="display: inline-block;width: 200px;"></el-input>
    <el-input v-model="queryInfo.minAge" placeholder="请输入最小年龄"
              style="display: inline-block;width: 200px;"></el-input>
    <el-input v-model="queryInfo.maxAge" placeholder="请输入最大年龄"
              style="display: inline-block;width: 200px;"></el-input>
    <el-button type="primary" icon="el-icon-search" @click="searchData()">搜索</el-button>
    <el-button type="primary">上传<i class="el-icon-upload el-icon--right"></i></el-button>
    <el-button type="primary">下载<i class="el-icon-download el-icon--right"></i></el-button>
    <el-button type="success" round @click="openAddStu()">添加学生</el-button>

    <el-table
            :data="tableData"
            border
            style="width: 100%">
        <el-table-column
                prop="id"
                label="编号"
        >
        </el-table-column>
        <el-table-column
                prop="name"
                label="姓名"
        >
        </el-table-column>
        <el-table-column
                prop="age"
                label="年龄">
        </el-table-column>
        <el-table-column
                prop="address"
                label="地址">
        </el-table-column>
        <el-table-column
                label="班级">
            <template slot-scope="scope">
                {{scope.row.grade.gname}}
            </template>
        </el-table-column>
        <el-table-column
                label="头像">
            <template slot-scope="scope">
                <img v-bind:src="scope.row.headImg" width="50px"/>
            </template>
        </el-table-column>
        <el-table-column
                label="操作">
            <template slot-scope="scope">
                <el-button @click="deleteStudent(scope.row.id)" type="danger" icon="el-icon-delete" circle></el-button>
                <el-button @click="openUpdateStu(scope.row.id)" type="primary" icon="el-icon-edit" circle></el-button>
            </template>
        </el-table-column>
    </el-table>

    <el-pagination
            @size-change="handleSizeChange"
            @current-change="handleCurrentChange"
            :current-page="1"
            :page-sizes="[5, 10, 15, 20]"
            :page-size="5"
            layout="total, sizes, prev, pager, next, jumper"
            :total="t">
    </el-pagination>

    <el-dialog :title="titlename" :visible.sync="dialogFormVisible">
        <el-form :model="stuInfo" :rules="rules" ref="stuInfo">
            <el-form-item label="学生姓名" prop="sname">
                <el-input v-model="stuInfo.sname" autocomplete="off"></el-input>
            </el-form-item>
            <el-form-item label="学生年龄" prop="sage">
                <el-input v-model="stuInfo.sage" autocomplete="off"></el-input>
            </el-form-item>
            <el-form-item label="学生地址" prop="saddress">
                <el-input v-model="stuInfo.saddress" autocomplete="off"></el-input>
            </el-form-item>
            <el-form-item label="学生班级" prop="gid">
                <el-select placeholder="请选择班级" v-model="stuInfo.gid">
                    <el-option v-for="g in gradeArr" :label="g.gname" :value="g.id"></el-option>
                </el-select>
            </el-form-item>
        </el-form>
        <div slot="footer" class="dialog-footer">
            <el-button @click="dialogFormVisible = false">取 消</el-button>
            <el-button type="primary" @click="addStudent()">确 定</el-button>
        </div>
    </el-dialog>
</div>

<script>

    var app = new Vue({
        el: "#app",
        data: {
            titlename: "",
            dialogFormVisible: false,
            queryInfo: {},
            stuInfo: {},
            tableData: [],
            gradeArr: [],
            size: 5,
            t: 100,
            rules: {
                sname: [
                    {required: true, message: '请输入姓名', trigger: 'blur'},
                ],
                sage: [
                    {required: true, message: '请输入年龄', trigger: 'blur'},
                ],
                saddress: [
                    {required: true, message: '请输入地址', trigger: 'blur'},
                ],
                gid: [
                    {required: true, message: '请选择班级', trigger: 'blur'},
                ]
            }
        },
        methods: {
            openUpdateStu(id) {
                //请求班级的数据
                $.get("/ssm/grade/list", function (backData) {
                    app.gradeArr = backData.data
                    $.get("/ssm/stu/get/" + id, function (backData) {
                        app.stuInfo = backData.data
                        app.titlename = "修改学生"
                        app.dialogFormVisible = true
                    })
                })
            },
            addStudent() {
                this.$refs["stuInfo"].validate((valid) => {
                    if (valid) {
                        var path = app.titlename === "添加学生" ? "/ssm/stu/add" : "/ssm/stu/update"
                        //发送ajax请求到后台
                        $.post(path, app.stuInfo, function (backData) {
                            if (backData.code == 1) {
                                app.$message({
                                    type: 'success',
                                    message: '操作成功!'
                                });
                                window.location.reload()
                            } else {
                                app.$message({
                                    type: 'danger',
                                    message: '操作失败!'
                                });
                            }
                        })
                    }
                });
            },
            openAddStu() {
                //请求班级的数据
                $.get("/ssm/grade/list", function (backData) {
                    app.gradeArr = backData.data
                    app.stuInfo = {}
                    app.titlename = "添加学生"
                    app.dialogFormVisible = true
                })
            },
            deleteStudent(id) {
                this.$confirm('此操作将永久删除该文件, 是否继续?', '提示', {
                    confirmButtonText: '确定',
                    cancelButtonText: '取消',
                    type: 'warning'
                }).then(() => {

                    $.get("/ssm/stu/delete/" + id, function (backData) {
                        if (backData.code === 1) {
                            app.$message({
                                type: 'success',
                                message: '删除成功!'
                            });

                            window.location.reload()
                        } else {
                            app.$message({
                                type: 'danger',
                                message: '删除失败!'
                            });
                        }

                    });
                });
            },
            handleSizeChange(val) {
                app.size = val
                getStudentData(1, app.size)
            },
            handleCurrentChange(val) {
                getStudentData(val, app.size)
            },
            searchData() {
                getStudentData(1, app.size)
            }
        }
    })
    
    function getStudentData(a, b) {
        app.queryInfo.pageNo = a;
        app.queryInfo.pageCount = b;
        $.post("/ssm/stu/query", app.queryInfo, function (backData) {
            app.tableData = backData.data.currentData
            app.t = backData.data.totalCount
        })
    }
    
    getStudentData(1, 5)
</script>
</body>
</html>

在数据正常展示时，页面效果如下

在这里插入图片描述

接下来进行数据的增删改查操作,此处只进行流程分析，源码在文章后边

3流程分析

当我们进入到学生管理界面，首先需要查询数据库中的数据，并且把他显示在页面当中

我们使用的是ElementUI提供的分页查询的代码。首先要发送post请求到"/ssm/stu/query"获取数据

在controller文件夹下创建StudentController用来处理请求的分发其中包括有
1. 获取全部学生数据
2. 根据ID删除学生
3. 添加学生
4. 根据ID获取单个学生
5. 更新学生信息
在StudentController接收到请求时会调用service层的方法
首先有一个StudentService接口其中写了上述的五个方法
在新建StudentService的实现类，其中写的是业务处理的具体流程
在实现类中，我们想要实现业务需求，我们就要去调用mapper层中的方法去连接数据库进行数据的读取
mapper层又要去找对应的mapper.xml配置文件进行sql语句的编写

所以这是一个连贯的过程，这里不再过多赘述

当获取到的数据响应到页面，这时一个完整的业务流程才算完毕

我们在实现类中可能会遇到实体类传参所以还要新建一些实体类，这些类放在pojo文件夹下

源码如下

4.controller层

4.1StudentController

package com.aaa.ssm.controller;

import com.aaa.ssm.pojo.vo.StudentQuery;
import com.aaa.ssm.pojo.vo.StudentVO;
import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Author Grg
 * @Date 2023/9/18 17:49
 * @PackageName:com.aaa.ssm.controller
 * @ClassName: StudentController
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */

@RestController
@RequestMapping("stu")
public class StudentController {

    @Autowired
    private StudentService studentService;

    @RequestMapping("query")
    public AjaxResult queryStudent(StudentQuery query) {
        return studentService.queryStudent(query);
    }

    @RequestMapping("delete/{id}")
    public AjaxResult deleteStudent(@PathVariable("id") Integer id) {
        return studentService.deleteStudent(id);
    }

    @RequestMapping("add")
    public AjaxResult addStudent(StudentVO studentVO) {

        return studentService.addStudent(studentVO);
    }
    @RequestMapping("get/{id}")
    public AjaxResult getStudentById(@PathVariable("id") Integer id) {
        return studentService.getStudentById(id);
    }

    @RequestMapping("update")
    public AjaxResult updateStudent(StudentVO studentVO) {
        return studentService.updateStudent(studentVO);
    }

}

4.2EmpController

package com.aaa.ssm.controller;

import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.EmpService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Author Grg
 * @Date 2023/9/17 14:49
 * @PackageName:com.aaa.ssm.controller
 * @ClassName: EmpController
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@RestController
@RequestMapping("emp")
public class EmpController {

    @Autowired
    private EmpService empService;


    @RequestMapping("login")
    public AjaxResult login(String username, String password) {
        return empService.login(username, password);
    }

    @RequestMapping("getInfo")
    public AjaxResult getInfo() {
        return empService.getInfo();
    }
}

4.3GradeController

package com.aaa.ssm.controller;
import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.GradeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Author Grg
 * @Date 2023/9/18 17:49
 * @PackageName:com.aaa.ssm.controller
 * @ClassName: StudentController
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */

@RestController
@RequestMapping("grade")
public class GradeController {

    @Autowired
    private GradeService gradeService;

    @RequestMapping("list")
    public AjaxResult queryStudent() {
        return gradeService.listAllGrade();
    }
}

5.mapper层

5.1EmpMapper

package com.aaa.ssm.mapper;
import com.aaa.ssm.pojo.dto.EmpDTO;
import com.aaa.ssm.pojo.dto.LoginDTO;
import org.apache.ibatis.annotations.Param;
/**
 * @Author Grg
 * @Date 2023/9/17 15:02
 * @PackageName:com.aaa.ssm.mapper
 * @ClassName: EmpMapper
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface EmpMapper {
    LoginDTO login(@Param("username")String username,@Param("password") String password);
    EmpDTO getEmpInfoByEid(Integer eid);
}

5.2GradeMapper

package com.aaa.ssm.mapper;
import com.aaa.ssm.pojo.dto.GradeDTO;
import java.util.List;
/**
 * @Author Grg
 * @Date 2023/9/19 15:02
 * @PackageName:com.aaa.ssm.mapper
 * @ClassName: GradeMapper
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface GradeMapper {
    List<GradeDTO> listAllGrades();
}

5.3PermissionMapper

package com.aaa.ssm.mapper;
import com.aaa.ssm.pojo.dto.PermissionDTO;
import java.util.List;
/**
 * @Author Grg
 * @Date 2023/9/18 15:13
 * @PackageName:com.aaa.ssm.mapper
 * @ClassName: PermissionMapper
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface PermissionMapper {
    List<PermissionDTO> listSuperAdminPermissions();
    List<PermissionDTO> listNormalAdminPermissions(Integer rid);
}

5.4StudentMapper

package com.aaa.ssm.mapper;
import com.aaa.ssm.pojo.dto.StudentDTO;
import com.aaa.ssm.pojo.vo.StudentQuery;
import com.aaa.ssm.pojo.vo.StudentVO;
import java.util.List;
/**
 * @Author Grg
 * @Date 2023/9/18 17:55
 * @PackageName:com.aaa.ssm.mapper
 * @ClassName: StudentMapper
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface StudentMapper {
    List<StudentDTO> queryStudentByQuery(StudentQuery query);
    Long queryStudentTotalCount(StudentQuery query);
    int deleteStudentById(Integer id);
    int addStudent(StudentVO studentVO);
    StudentVO getStudentById(Integer id);
    int uptateStudent(StudentVO studentVO);
}

6.pojo

6.1dto

6.1.1DeptDTO

package com.aaa.ssm.pojo.dto;
import lombok.Data;
import java.io.Serializable;
/**
 * @Author Grg
 * @Date 2023/9/17 15:22
 * @PackageName:com.aaa.ssm.pojo.dto
 * @ClassName: DeptDTO
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Data
public class DeptDTO implements Serializable {
    private Integer id;
    private String dname;
    private String other;
    private Integer state;
}

6.1.2EmpDTO

package com.aaa.ssm.pojo.dto;
import lombok.Data;
import java.io.Serializable;

/**
 * @Author Grg
 * @Date 2023/9/17 15:20
 * @PackageName:com.aaa.ssm.pojo.dto
 * @ClassName: EmpDTO
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Data
public class EmpDTO implements Serializable {
    private Integer id;
    private String ename;
    private String hiredate;
    private String telephone;
    private DeptDTO dept;
    private RoleDTO role;
}

6.2vo

6.2.1StudentVO

package com.aaa.ssm.pojo.vo;
import lombok.Data;
import java.io.Serializable;
/**
 * @Author Grg
 * @Date 2023/9/19 15:45
 * @PackageName:com.aaa.ssm.pojo.vo
 * @ClassName: StudentVO
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Data
public class StudentVO implements Serializable {
    private Integer id;
    private String sname;
    private Integer sage;
    private String saddress;
    private Integer gid;
}

当然不止这些，还有好几个（懒得写了，实在头皮发麻）这些类主要就是用来接收参数用的

这一块需要注意的是，我们的数据库中其实是有外键的，虽然是逻辑外键。我们在新建类中可以看到，在类中有私有的成员对象，我们使用这种方法来凸显外键的作用

剩下的在这里就放张截图叭

在这里插入图片描述

7.result

用来接收AJAX请求返回结果

AjaxResult

package com.aaa.ssm.result;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @Author Grg
 * @Date 2023/8/28 15:58
 * @PackageName:com.grg.Result
 * @ClassName: AjaxResult
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class AjaxResult {
    private Integer code;
    private String msg;
    private Object data;


    public static AjaxResult success() {
        return new AjaxResult(1,"操作成功",null);
    }
    public static AjaxResult success(Object data) {
        return new AjaxResult(1,"操作成功",data);
    }
    public static AjaxResult error() {
        return new AjaxResult(2,"操作失败",null);
    }
    public static AjaxResult error(String msg) {
        return new AjaxResult(2,msg,null);
    }

}

8.service

8.1impl实现类

8.1.1EmpServiceImpl

package com.aaa.ssm.service.impl;

import com.aaa.ssm.mapper.EmpMapper;
import com.aaa.ssm.mapper.PermissionMapper;
import com.aaa.ssm.pojo.dto.EmpDTO;
import com.aaa.ssm.pojo.dto.LoginDTO;
import com.aaa.ssm.pojo.dto.PermissionDTO;
import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.EmpService;
import com.aaa.ssm.sysconst.DeptState;
import com.aaa.ssm.sysconst.EmpState;
import com.aaa.ssm.util.PermissionUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpSession;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

/**
 * @Author Grg
 * @Date 2023/9/17 15:00
 * @PackageName:com.aaa.ssm.service.impl
 * @ClassName: EmpServiceImpl
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Service
public class EmpServiceImpl implements EmpService {

    @Autowired
    private EmpMapper empMapper;

    @Autowired
    private PermissionMapper permissionMapper;

    @Autowired
    private HttpSession session;

    @Override
    public AjaxResult login(String username, String password) {
        //1.验证账号密码是否正确
        LoginDTO login = empMapper.login(username, password);

        //1.5账号的状态是什么 state 0在职  1冻结  2离职
        if (login == null) {
            return AjaxResult.error("账号或者密码错误");
        }
        if (login.getState() == EmpState.EMP_DONGJIE) {
            return AjaxResult.error("账号被冻结");
        }
        if (login.getState() == EmpState.EMP_LIZHI) {
            return AjaxResult.error("员工已经离职 联系管理员");
        }
        //2.如果正确 获取员工编号 查询员工信息
        Integer eid = login.getEid();
        EmpDTO empInfo = empMapper.getEmpInfoByEid(eid);

        if (empInfo.getDept().getState() == DeptState.DEPT_STATE_BILE) {
            return AjaxResult.error("部门已倒闭 请联系主管");
        }

        //登录成功
        //将当前用户信息存储近Session中
        session.setAttribute("emp", empInfo);
        return AjaxResult.success();
    }

    @Override
    public AjaxResult getInfo() {
        EmpDTO empInfo = (EmpDTO) session.getAttribute("emp");
        HashMap<Object, Object> map = new HashMap<>();
        map.put("userInfo", empInfo);

        Integer state = empInfo.getRole().getState();
        if (state == 1) {
            return AjaxResult.success(map);
        }

        List<PermissionDTO> permissionDTOS = null;
        Integer rid = empInfo.getRole().getId();
        if (rid == 1) {
            //超级管理员权限
            permissionDTOS = permissionMapper.listSuperAdminPermissions();
        } else {
            //普通管理员
            permissionDTOS = permissionMapper.listNormalAdminPermissions(rid);
        }
        List<PermissionDTO> data = PermissionUtil.handlerData(permissionDTOS);
        map.put("permissionInfo", data);
        return AjaxResult.success(map);
    }
}

8.1.2GradeServiceImpl

package com.aaa.ssm.service.impl;

import com.aaa.ssm.mapper.GradeMapper;
import com.aaa.ssm.pojo.dto.GradeDTO;
import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.GradeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @Author Grg
 * @Date 2023/9/19 15:00
 * @PackageName:com.aaa.ssm.service.impl
 * @ClassName: GradeServiceImpl
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Service
public class GradeServiceImpl implements GradeService {

    @Autowired
    private GradeMapper gradeMapper;

    @Override
    public AjaxResult listAllGrade() {
        List<GradeDTO> gradeDTOS = gradeMapper.listAllGrades();

        return AjaxResult.success(gradeDTOS);
    }
}

8.1.3StudentServiceImpl

package com.aaa.ssm.service.impl;

import com.aaa.ssm.mapper.StudentMapper;
import com.aaa.ssm.pojo.dto.StudentDTO;
import com.aaa.ssm.pojo.vo.StudentQuery;
import com.aaa.ssm.pojo.vo.StudentVO;
import com.aaa.ssm.result.AjaxResult;
import com.aaa.ssm.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.HashMap;
import java.util.List;

/**
 * @Author Grg
 * @Date 2023/9/18 17:53
 * @PackageName:com.aaa.ssm.service.impl
 * @ClassName: StudentImpl
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    @Override
    public AjaxResult queryStudent(StudentQuery query) {
        List<StudentDTO> studentDTOS = studentMapper.queryStudentByQuery(query);
        Long totalCount = studentMapper.queryStudentTotalCount(query);
        HashMap<Object, Object> map = new HashMap<>();
        map.put("currentData", studentDTOS);
        map.put("totalCount", totalCount);
        return AjaxResult.success(map);
    }

    @Override
    public AjaxResult deleteStudent(Integer id) {
        int i = studentMapper.deleteStudentById(id);
        if (i > 0) {
            return AjaxResult.success();
        } else {
            return AjaxResult.error("删除失败");
        }
    }

    @Override
    public AjaxResult addStudent(StudentVO studentVO) {
        System.out.println(studentVO);
        int i = studentMapper.addStudent(studentVO);
        if (i > 0) {
            return AjaxResult.success();
        } else {
            return AjaxResult.error("添加失败");
        }
    }

    @Override
    public AjaxResult getStudentById(Integer id) {
        StudentVO student = studentMapper.getStudentById(id);
        return AjaxResult.success(student);
    }

    @Override
    public AjaxResult updateStudent(StudentVO studentVO) {
        int i = studentMapper.uptateStudent(studentVO);
        if (i > 0) {
            return AjaxResult.success();
        } else {
            return AjaxResult.error("修改失败");
        }
    }
}

8.2EmpService

package com.aaa.ssm.service;

import com.aaa.ssm.result.AjaxResult;

/**
 * @Author Grg
 * @Date 2023/9/17 14:58
 * @PackageName:com.aaa.ssm.service
 * @ClassName: EmpService
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface EmpService {
    AjaxResult login(String username, String password);

    AjaxResult getInfo();
}

8.3GradeService

package com.aaa.ssm.service;

import com.aaa.ssm.result.AjaxResult;

/**
 * @Author Grg
 * @Date 2023/9/19 14:59
 * @PackageName:com.aaa.ssm.service
 * @ClassName: GradeService
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface GradeService {
    AjaxResult listAllGrade();
}

8.4StudentService

package com.aaa.ssm.service;

import com.aaa.ssm.pojo.vo.StudentQuery;
import com.aaa.ssm.pojo.vo.StudentVO;
import com.aaa.ssm.result.AjaxResult;

/**
 * @Author Grg
 * @Date 2023/9/18 17:52
 * @PackageName:com.aaa.ssm.service
 * @ClassName: StudentService
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public interface StudentService {

    AjaxResult queryStudent(StudentQuery query);

    AjaxResult deleteStudent(Integer id);

    AjaxResult addStudent(StudentVO studentVO);

    AjaxResult getStudentById(Integer id);

    AjaxResult updateStudent(StudentVO studentVO);
}

9.util工具类

9.1PermissionUtil

这个是在登陆时，根据登录账号的权限不同展示的数据和能进行的操作也不一样

package com.aaa.ssm.util;

import com.aaa.ssm.pojo.dto.PermissionDTO;

import java.util.ArrayList;
import java.util.List;

/**
 * @Author Grg
 * @Date 2023/9/18 15:58
 * @PackageName:com.aaa.ssm.util
 * @ClassName: PermissionUtil
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public class PermissionUtil {
    public static List<PermissionDTO> handlerData(List<PermissionDTO> permissionDTOS){
        ArrayList<PermissionDTO> data = new ArrayList<>();

        for (PermissionDTO permissionDTO : permissionDTOS) {
            if (permissionDTO.getPid() == 0) {
                data.add(permissionDTO);
            }
        }
        for (PermissionDTO permissionDTO : permissionDTOS) {
            Integer pid = permissionDTO.getPid();
            for (PermissionDTO datum : data) {
                if (datum.getId().equals(pid)) {
                    datum.getSubMenu().add(permissionDTO);
                }
            }
        }
        return data;
    }
}

10.mapper.xml

10.1EmpMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.aaa.ssm.mapper.EmpMapper">

    <select id="login" resultType="com.aaa.ssm.pojo.dto.LoginDTO">
        select * from t_emp_login where username = #{username} and password = #{password};
    </select>

    <resultMap id="empInfo" type="empDTO">
        <id column="id" property="id"></id>
        <result column="ename" property="ename"></result>
        <result column="hiredate" property="hiredate"></result>
        <result column="telephone" property="telephone"></result>

        <association property="dept" javaType="deptDTO">
            <id column="did" property="id"></id>
            <result column="dname" property="dname"></result>
            <result column="dstate" property="state"></result>
        </association>
        <association property="role" javaType="roleDTO">
            <id column="rid" property="id"></id>
            <result column="rname" property="rname"></result>
            <result column="rstate" property="state"></result>
        </association>
    </resultMap>

    <select id="getEmpInfoByEid" resultMap="empInfo">
        SELECT e.id,
               e.ename,
               e.hiredate,
               e.telephone,
               d.id    did,
               d.dname,
               d.other,
               d.state dstate,
               r.id    rid,
               r.rname,
               r.state rstate
        from t_emp_info e
                 LEFT JOIN t_dept d on e.did = d.id
                 LEFT JOIN t_role r on e.rid = r.id
        where e.id = #{eid};
    </select>
</mapper>

10.2GradeMapper

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.aaa.ssm.mapper.GradeMapper">


    <select id="listAllGrades" resultType="com.aaa.ssm.pojo.dto.GradeDTO">
        select *
        from t_grade
        where state = 0;
    </select>
</mapper>

10.3PermissionMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.aaa.ssm.mapper.PermissionMapper">

    <select id="listSuperAdminPermissions" resultType="com.aaa.ssm.pojo.dto.PermissionDTO">
        select id, pid, type, pname title, url content, state, icon
        from t_perm
    </select>
    <select id="listNormalAdminPermissions" resultType="com.aaa.ssm.pojo.dto.PermissionDTO">
        select p.id, p.pid, p.type, p.pname title, p.url content, p.state, p.icon
        from t_rp tp
                 left join t_perm p on tp.pid = p.id
        where tp.rid = #{rid}
          and p.state = 0
    </select>
</mapper>

10.4StudentMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.aaa.ssm.mapper.StudentMapper">


    <resultMap id="StudentMap" type="com.aaa.ssm.pojo.dto.StudentDTO">
        <id column="id" property="id"></id>
        <result column="name" property="name"></result>
        <result column="age" property="age"></result>
        <result column="address" property="address"></result>
        <result column="headImg" property="headImg"></result>

        <association property="grade" javaType="com.aaa.ssm.pojo.dto.GradeDTO">
            <id column="tid" property="id"></id>
            <result column="gname" property="gname"></result>
            <result column="state" property="state"></result>
        </association>
    </resultMap>
    <sql id="queryStu">
        <where>
            <if test="name != null and '' != name">
                and ts.name like concat('%',#{name},'%')
            </if>
            <if test="minAge != null and '' != minAge">
                and ts.age &gt; #{minAge}
            </if>
            <if test="maxAge != null and '' != maxAge">
                and ts.age &lt; #{maxAge}
            </if>
        </where>
    </sql>
    <insert id="addStudent">
        insert into t_student ( name, age, address, gid) values (#{sname},#{sage},#{saddress},#{gid})
    </insert>
    <update id="uptateStudent">
        update t_student
        SET name    = #{sname},
            age     = #{sage},
            address = #{saddress},
            gid= #{gid}
        where id = #{id}
    </update>
    <delete id="deleteStudentById">
        delete
        from t_student
        where id = #{id}
    </delete>

    <select id="queryStudentByQuery" resultMap="StudentMap">
        select ts.id,
        ts.name,
        ts.age,
        ts.address,
        ts.headImg,
        tg.id tid,
        tg.gname,
        tg.state
        from t_student ts
        left join t_grade tg
        on ts.gid = tg.id
        <include refid="queryStu"></include>
        limit #{index},#{pageCount}
    </select>
    <select id="queryStudentTotalCount" resultType="java.lang.Long">
        select count(*) from t_student ts
        <include refid="queryStu"></include>
    </select>
    <select id="getStudentById" resultType="com.aaa.ssm.pojo.vo.StudentVO">
        select id, name sname, age sage, address saddress, gid
        from t_student
        where id = #{id}
    </select>
</mapper>