fix:树结构查询

src/main/java/com/kwan/springbootkwan/controller/DepartmentController.java

+package com.kwan.springbootkwan.controller;
+
+import com.kwan.springbootkwan.entity.Department;
+import com.kwan.springbootkwan.service.DepartmentService;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import javax.annotation.Resource;
+import java.util.List;
+
+/**
+ * 部门(Department)表控制层
+ *
+ * @author makejava
+ * @since 2023-08-28 22:17:33
+ */
+@RestController
+@RequestMapping("department")
+public class DepartmentController {
+    /**
+     * 服务对象
+     */
+    @Resource
+    private DepartmentService departmentService;
+
+    /**
+     * 分页查询
+     *
+     * @param department  筛选条件
+     * @param pageRequest 分页对象
+     * @return 查询结果
+     */
+    @GetMapping
+    public ResponseEntity<Page<Department>> queryByPage(Department department, PageRequest pageRequest) {
+        return ResponseEntity.ok(this.departmentService.queryByPage(department, pageRequest));
+    }
+
+    /**
+     * 通过主键查询单条数据
+     *
+     * @param id 主键
+     * @return 单条数据
+     */
+    @GetMapping("{id}")
+    public ResponseEntity<Department> queryById(@PathVariable("id") Integer id) {
+        //已知id=16,查询树结构
+        return ResponseEntity.ok(this.departmentService.queryById(id));
+    }
+
+    /**
+     * 已知id查询树结构
+     *
+     * @param id
+     * @return
+     */
+    @GetMapping("/tree/{id}")
+    public ResponseEntity<Department> queryTreeById(@PathVariable("id") Integer id) {
+        //已知id=16,查询树结构
+        return ResponseEntity.ok(this.departmentService.queryTreeById(id));
+    }
+
+
+    @GetMapping("/all")
+    public ResponseEntity<List<Department>> queryTreeAll() {
+        return ResponseEntity.ok(this.departmentService.queryTreeAll());
+    }
+
+    /**
+     * 新增数据
+     *
+     * @param department 实体
+     * @return 新增结果
+     */
+    @PostMapping
+    public ResponseEntity<Department> add(Department department) {
+        return ResponseEntity.ok(this.departmentService.insert(department));
+    }
+
+    /**
+     * 编辑数据
+     *
+     * @param department 实体
+     * @return 编辑结果
+     */
+    @PutMapping
+    public ResponseEntity<Department> edit(Department department) {
+        return ResponseEntity.ok(this.departmentService.update(department));
+    }
+
+    /**
+     * 删除数据
+     *
+     * @param id 主键
+     * @return 删除是否成功
+     */
+    @DeleteMapping
+    public ResponseEntity<Boolean> deleteById(Integer id) {
+        return ResponseEntity.ok(this.departmentService.deleteById(id));
+    }
+}
\ No newline at end of file

src/main/java/com/kwan/springbootkwan/entity/Department.java

+package com.kwan.springbootkwan.entity;
+
+import lombok.Data;
+
+import java.util.Date;
+import java.io.Serializable;
+import java.util.List;
+
+/**
+ * 部门(Department)实体类
+ *
+ * @author makejava
+ * @since 2023-08-28 22:17:34
+ */
+@Data
+public class Department implements Serializable {
+    private static final long serialVersionUID = -95673125287393878L;
+
+    private Integer id;
+
+    private String deptName;
+
+    private Integer parentId;
+
+    private String remark;
+
+    private Date createdAt;
+
+    private Integer deleted;
+
+    private List<Department> children;
+}
\ No newline at end of file

src/main/java/com/kwan/springbootkwan/mapper/DepartmentMapper.java

+package com.kwan.springbootkwan.mapper;
+
+import com.kwan.springbootkwan.entity.Department;
+import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+import org.springframework.data.domain.Pageable;
+
+import java.util.List;
+
+/**
+ * 部门(Department)表数据库访问层
+ *
+ * @author makejava
+ * @since 2023-08-28 22:17:33
+ */
+@Mapper
+public interface DepartmentMapper {
+
+    /**
+     * 通过ID查询单条数据
+     *
+     * @param id 主键
+     * @return 实例对象
+     */
+    Department queryById(Integer id);
+
+    /**
+     * 查询指定行数据
+     *
+     * @param department 查询条件
+     * @param pageable   分页对象
+     * @return 对象列表
+     */
+    List<Department> queryAllByLimit(Department department, @Param("pageable") Pageable pageable);
+
+    /**
+     * 统计总行数
+     *
+     * @param department 查询条件
+     * @return 总行数
+     */
+    long count(Department department);
+
+    /**
+     * 新增数据
+     *
+     * @param department 实例对象
+     * @return 影响行数
+     */
+    int insert(Department department);
+
+    /**
+     * 批量新增数据（MyBatis原生foreach方法）
+     *
+     * @param entities List<Department> 实例对象列表
+     * @return 影响行数
+     */
+    int insertBatch(@Param("entities") List<Department> entities);
+
+    /**
+     * 批量新增或按主键更新数据（MyBatis原生foreach方法）
+     *
+     * @param entities List<Department> 实例对象列表
+     * @return 影响行数
+     * @throws org.springframework.jdbc.BadSqlGrammarException 入参是空List的时候会抛SQL语句错误的异常，请自行校验入参
+     */
+    int insertOrUpdateBatch(@Param("entities") List<Department> entities);
+
+    /**
+     * 修改数据
+     *
+     * @param department 实例对象
+     * @return 影响行数
+     */
+    int update(Department department);
+
+    /**
+     * 通过主键删除数据
+     *
+     * @param id 主键
+     * @return 影响行数
+     */
+    int deleteById(Integer id);
+
+    /**
+     * 根据父id查询数据
+     *
+     * @param parentId
+     * @return
+     */
+    List<Department> queryByParentId(@Param("parentId") Integer parentId);
+}
+

src/main/java/com/kwan/springbootkwan/service/DepartmentService.java

+package com.kwan.springbootkwan.service;
+
+import com.kwan.springbootkwan.entity.Department;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+
+import java.util.List;
+
+/**
+ * 部门(Department)表服务接口
+ *
+ * @author makejava
+ * @since 2023-08-28 22:17:34
+ */
+public interface DepartmentService {
+
+    /**
+     * 通过ID查询单条数据
+     *
+     * @param id 主键
+     * @return 实例对象
+     */
+    Department queryById(Integer id);
+
+    /**
+     * 分页查询
+     *
+     * @param department  筛选条件
+     * @param pageRequest 分页对象
+     * @return 查询结果
+     */
+    Page<Department> queryByPage(Department department, PageRequest pageRequest);
+
+    /**
+     * 新增数据
+     *
+     * @param department 实例对象
+     * @return 实例对象
+     */
+    Department insert(Department department);
+
+    /**
+     * 修改数据
+     *
+     * @param department 实例对象
+     * @return 实例对象
+     */
+    Department update(Department department);
+
+    /**
+     * 通过主键删除数据
+     *
+     * @param id 主键
+     * @return 是否成功
+     */
+    boolean deleteById(Integer id);
+
+    /**
+     * 根据id查询部门
+     *
+     * @param id
+     * @return
+     */
+    Department queryTreeById(Integer id);
+
+    /**
+     * 查询所有部门
+     *
+     * @return
+     */
+    List<Department> queryTreeAll();
+}

src/main/java/com/kwan/springbootkwan/service/impl/DepartmentServiceImpl.java

+package com.kwan.springbootkwan.service.impl;
+
+import com.kwan.springbootkwan.entity.Department;
+import com.kwan.springbootkwan.mapper.DepartmentMapper;
+import com.kwan.springbootkwan.service.DepartmentService;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.stereotype.Service;
+import org.springframework.util.CollectionUtils;
+
+import javax.annotation.Resource;
+import java.util.List;
+
+/**
+ * 部门(Department)表服务实现类
+ *
+ * @author makejava
+ * @since 2023-08-28 22:17:34
+ */
+@Service("departmentService")
+public class DepartmentServiceImpl implements DepartmentService {
+    @Resource
+    private DepartmentMapper departmentDao;
+
+    /**
+     * 通过ID查询单条数据
+     *
+     * @param id 主键
+     * @return 实例对象
+     */
+    @Override
+    public Department queryById(Integer id) {
+        return this.departmentDao.queryById(id);
+    }
+
+    /**
+     * 分页查询
+     *
+     * @param department  筛选条件
+     * @param pageRequest 分页对象
+     * @return 查询结果
+     */
+    @Override
+    public Page<Department> queryByPage(Department department, PageRequest pageRequest) {
+        long total = this.departmentDao.count(department);
+        return new PageImpl<>(this.departmentDao.queryAllByLimit(department, pageRequest), pageRequest, total);
+    }
+
+    /**
+     * 新增数据
+     *
+     * @param department 实例对象
+     * @return 实例对象
+     */
+    @Override
+    public Department insert(Department department) {
+        this.departmentDao.insert(department);
+        return department;
+    }
+
+    /**
+     * 修改数据
+     *
+     * @param department 实例对象
+     * @return 实例对象
+     */
+    @Override
+    public Department update(Department department) {
+        this.departmentDao.update(department);
+        return this.queryById(department.getId());
+    }
+
+    /**
+     * 通过主键删除数据
+     *
+     * @param id 主键
+     * @return 是否成功
+     */
+    @Override
+    public boolean deleteById(Integer id) {
+        return this.departmentDao.deleteById(id) > 0;
+    }
+
+    @Override
+    public Department queryTreeById(Integer id) {
+        Department departmentDTO = new Department();
+        departmentDTO.setId(0);
+        queryChildren(departmentDTO);
+        return departmentDTO;
+    }
+
+    @Override
+    public List<Department> queryTreeAll() {
+        //先找出父id为0的部门
+        List<Department> children = departmentDao.queryByParentId(0);
+        for (Department child : children) {
+            child.setChildren(queryChildren(child));
+        }
+        return children;
+    }
+
+    /**
+     * 递归查询
+     *
+     * @param parent
+     */
+    private List<Department> queryChildren(Department parent) {
+        List<Department> children = departmentDao.queryByParentId(parent.getId());
+        if (CollectionUtils.isEmpty(children)) {
+            return null;
+        }
+        for (Department child : children) {
+            child.setChildren(queryChildren(child));
+        }
+        return children;
+    }
+}
\ No newline at end of file

src/main/resources/mapper/DepartmentMapper.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.kwan.springbootkwan.mapper.DepartmentMapper">
+
+    <resultMap type="com.kwan.springbootkwan.entity.Department" id="DepartmentMap">
+        <result property="id" column="id" jdbcType="INTEGER"/>
+        <result property="deptName" column="dept_name" jdbcType="VARCHAR"/>
+        <result property="parentId" column="parent_id" jdbcType="INTEGER"/>
+        <result property="remark" column="remark" jdbcType="VARCHAR"/>
+        <result property="createdAt" column="created_at" jdbcType="TIMESTAMP"/>
+        <result property="deleted" column="deleted" jdbcType="INTEGER"/>
+    </resultMap>
+
+    <!--查询单个-->
+    <select id="queryById" resultMap="DepartmentMap">
+        SELECT id
+             , dept_name
+             , parent_id
+             , remark
+             , created_at
+             , deleted
+        FROM department
+        WHERE id = #{id}
+    </select>
+
+    <!--查询指定行数据-->
+    <select id="queryAllByLimit" resultMap="DepartmentMap">
+        select
+        id, dept_name, parent_id, remark, created_at, deleted
+        from department
+        <where>
+            <if test="id != null">
+                and id = #{id}
+            </if>
+            <if test="deptName != null and deptName != ''">
+                and dept_name = #{deptName}
+            </if>
+            <if test="parentId != null">
+                and parent_id = #{parentId}
+            </if>
+            <if test="remark != null and remark != ''">
+                and remark = #{remark}
+            </if>
+            <if test="createdAt != null">
+                and created_at = #{createdAt}
+            </if>
+            <if test="deleted != null">
+                and deleted = #{deleted}
+            </if>
+        </where>
+        limit #{pageable.offset}, #{pageable.pageSize}
+    </select>
+
+    <!--统计总行数-->
+    <select id="count" resultType="java.lang.Long">
+        select count(1)
+        from department
+        <where>
+            <if test="id != null">
+                and id = #{id}
+            </if>
+            <if test="deptName != null and deptName != ''">
+                and dept_name = #{deptName}
+            </if>
+            <if test="parentId != null">
+                and parent_id = #{parentId}
+            </if>
+            <if test="remark != null and remark != ''">
+                and remark = #{remark}
+            </if>
+            <if test="createdAt != null">
+                and created_at = #{createdAt}
+            </if>
+            <if test="deleted != null">
+                and deleted = #{deleted}
+            </if>
+        </where>
+    </select>
+    <select id="queryByParentId" resultMap="DepartmentMap">
+        SELECT id,dept_name, parent_id, remark, created_at, deleted
+        FROM department
+        WHERE 1=1
+        <if test="parentId != null">
+            AND parent_id = #{parentId}
+        </if>
+    </select>
+
+    <!--新增所有列-->
+    <insert id="insert" keyProperty="id" useGeneratedKeys="true">
+        INSERT INTO department(dept_name, parent_id, remark, created_at, deleted)
+        VALUES (#{deptName}, #{parentId}, #{remark}, #{createdAt}, #{deleted})
+    </insert>
+
+    <insert id="insertBatch" keyProperty="id" useGeneratedKeys="true">
+        insert into department(dept_name, parent_id, remark, created_at, deleted)
+        values
+        <foreach collection="entities" item="entity" separator=",">
+            (#{entity.deptName}, #{entity.parentId}, #{entity.remark}, #{entity.createdAt}, #{entity.deleted})
+        </foreach>
+    </insert>
+
+    <insert id="insertOrUpdateBatch" keyProperty="id" useGeneratedKeys="true">
+        insert into department(dept_name, parent_id, remark, created_at, deleted)
+        values
+        <foreach collection="entities" item="entity" separator=",">
+            (#{entity.deptName}, #{entity.parentId}, #{entity.remark}, #{entity.createdAt}, #{entity.deleted})
+        </foreach>
+        on duplicate key update
+        dept_name = values(dept_name),
+        parent_id = values(parent_id),
+        remark = values(remark),
+        created_at = values(created_at),
+        deleted = values(deleted)
+    </insert>
+
+    <!--通过主键修改数据-->
+    <update id="update">
+        update department
+        <set>
+            <if test="deptName != null and deptName != ''">
+                dept_name = #{deptName},
+            </if>
+            <if test="parentId != null">
+                parent_id = #{parentId},
+            </if>
+            <if test="remark != null and remark != ''">
+                remark = #{remark},
+            </if>
+            <if test="createdAt != null">
+                created_at = #{createdAt},
+            </if>
+            <if test="deleted != null">
+                deleted = #{deleted},
+            </if>
+        </set>
+        where id = #{id}
+    </update>
+
+    <!--通过主键删除-->
+    <delete id="deleteById">
+        DELETE
+        FROM department
+        WHERE id = #{id}
+    </delete>
+
+</mapper>
+