说明：在开发中，我们经常使用树形结构来展示菜单选项，如图：
那么我们在后端怎么去实现这样的一个功能呢？
1、数据库表：department
2、编写sql映射语句
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< select id = "selectDepartmentTrees" resultType = "com.welb.entity.Department" > select * from department < where > < if test = "updepartmentcode!=null" > and UpDepartmentCode=#{updepartmentcode} </ if >
</ where > </ select > |
3、创建实体类
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public class Department { private String departmentcode; //部门code
private String departmentname; //部门名称
private String updepartmentcode= "0" ; //上级部门
private String departmentdesc; //部门描述
private List<Department> childDept = new ArrayList(); //部门信息树
public String getDepartmentcode() { return departmentcode; }
public void setDepartmentcode(String departmentcode) { this .departmentcode = departmentcode == null ? null : departmentcode.trim(); }
public String getDepartmentname() { return departmentname; }
public void setDepartmentname(String departmentname) { this .departmentname = departmentname == null ? null : departmentname.trim(); }
public String getUpdepartmentcode() { return updepartmentcode; }
public void setUpdepartmentcode(String updepartmentcode) { this .updepartmentcode = updepartmentcode == null ? null : updepartmentcode.trim(); }
public String getDepartmentdesc() { return departmentdesc; }
public void setDepartmentdesc(String departmentdesc) { this .departmentdesc = departmentdesc == null ? null : departmentdesc.trim(); }
public List<Department> getChildDept() { return childDept; }
public void setChildDept(List<Department> childDept) { this .childDept = childDept; } } |
4、定义mapper
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@Mapper public interface DepartmentMapper { List<Department>selectDepartmentTrees(Department department); } |
5、定义service业务层实现
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@Service @Transactional public class DepartmentImpl implements IDepartmentService { @Resource DepartmentMapper departmentMapper;
@Override public List<Department> selectDepartmentTrees(Department department) { return departmentMapper.selectDepartmentTrees(department); } } |
6、控制层实现
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@RestController @RequestMapping ( "department" ) public class DepartmentController { @Resource IDepartmentService departmentService; @Resource IStationService stationService;
/** * 查询所有部门 树形展示所有部门 包含模糊查詢 * * @return */ @RequestMapping ( "/treelist" ) public Object selectAll(Department department) { ModelMap map = new ModelMap(); try { List<Department> departmentDtos = getDepartmentList(department); map.put( "msg" , "查询部门成功" ); map.put( "data" , departmentDtos); map.put( "code" , 0 ); } catch (Exception e) { e.printStackTrace(); map.put( "msg" , "查询部门失败" ); map.put( "code" , 1 ); } return map; }
/** * 递归查询部门 * @param department * @return */ private List<Department> getDepartmentList(Department department) { List<Department> departments =departmentService.selectDepartmentTrees(department); if (departments.size()> 0 ){ Department department1= new Department(); for ( int i = 0 ; i <departments.size() ; i++) { department1.setUpdepartmentcode(departments.get(i).getDepartmentcode()); List<Department>dtos=getDepartmentList(department1); departments.get(i).setChildDept(dtos); } } return departments; } } |
7、进行测试，这里我用postmain工具测试，结果如下图
到这里，递归查询部门树形结构数据就完成了
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原文链接：https://blog.csdn.net/qq_42570879/article/details/90386962
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