ElementUI组件Cascader级联选择器数据后台处理

Cascader级联选择器数据数据格式不知道的可以去官网看下；这里我就不表示什么了。

部门实体类：

 import lombok.Data;

 @Data

 public class Department {

     private Integer id;

     private Integer parentId;

     private String name;

     public Department(Integer id, Integer parentId, String name) {

         this.id = id;

         this.parentId = parentId;

         this.name = name;

     }

     public static TreeItem deptNode(Department dept) {

         TreeItem treeItem = new TreeItem();

         treeItem.setId(dept.getId());

         treeItem.setName(dept.getName());

         treeItem.setParentId(dept.getParentId());

         return treeItem;

     }

 }

用户实体类：

 import lombok.Data;

 @Data

 public class Employee {

     private Integer id;

     private String name;

     private Integer deptId;

     public Employee(Integer id, String name, Integer deptId) {

         this.id = id;

         this.name = name;

         this.deptId = deptId;

     }

     public static TreeItem empNode(Employee emp) {

         TreeItem treeItem = new TreeItem();

         treeItem.setId(emp.getId());

         treeItem.setName(emp.getName());

         treeItem.setParentId(emp.getDeptId());

         return treeItem;

     }

 }

返回数据实体类：

 import lombok.Data;

 import java.util.List;

 @Data

 public class TreeItem {

     private Integer id;

     private Integer parentId;

     private String name;

     private List<TreeItem> children;

 }

数据处理操作，这里是用java8新的特性写的。不懂的可以学习下，挺好用的

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.List;

 import java.util.Map;

 import java.util.stream.Collectors;

 public class App {

     public static void main(String[] args) {

         //创建部门

         List<Department> deptList = Arrays.asList(

                 new Department(1, 0, "星宇"),

                 new Department(2, 1, "金3"),

                 new Department(3, 2, "金3/1"),

                 new Department(4, 2, "金3/2"),

                 new Department(5, 1, "总1"),

                 new Department(6, 5, "总1/2")

         );

         //创建员工

         List<Employee> empList = Arrays.asList(

                 new Employee(1, "张三", 5),

                 new Employee(2, "李四", 6),

                 new Employee(3, "王五", 2),

                 new Employee(4, "赵六", 2),

                 new Employee(5, "田七", 3),

                 new Employee(6, "牛八", 4)

         );

         //转换成结点

         List<TreeItem> allDept = deptList.stream()

                 .map(Department::deptNode)

                 .collect(Collectors.toList());

         //按照上级部门分组

         Map<Integer, List<TreeItem>> deptMap = allDept.stream()

                 .collect(Collectors.groupingBy(TreeItem::getParentId));

         //给每个部门绑定子部门

         allDept.forEach(node ->

                 node.setChildren(deptMap.get(node.getId()))

         );

         List<TreeItem> treeItem = deptMap.get(0);

         Map<Integer, List<TreeItem>> empMap = empList.stream()

                 .filter(emp -> emp.getDeptId() != null)

                 .map(Employee::empNode)

                 .collect(Collectors.groupingBy(TreeItem::getParentId));

         //BFS辅助队列

         List<TreeItem> queue = new ArrayList<>();

         queue.addAll(treeItem);

         for (int i = 0; i < queue.size(); i++) {

             TreeItem node = queue.get(i);

             //遍历时先将子部门放入队列中

             if (node.getChildren() != null) {

                 queue.addAll(node.getChildren());

             } else {

                 node.setChildren(new ArrayList<>());

             }

             //再将部门成员放入子结点中

             List<TreeItem> children = empMap.get(node.getId());

             if (children != null) {

                 node.getChildren().addAll(children);

             }

         }

         treeItem.forEach(x -> System.out.println(x));

     }

 }

TreeItem(id=1, parentId=0, name=星宇, children=[TreeItem(id=2, parentId=1, name=金3, children=[TreeItem(id=3, parentId=2, name=金3/1, children=[TreeItem(id=5, parentId=3, name=田七, children=null)]), TreeItem(id=4, parentId=2, name=金3/2, children=[TreeItem(id=6, parentId=4, name=牛八, children=null)]), TreeItem(id=3, parentId=2, name=王五, children=null), TreeItem(id=4, parentId=2, name=赵六, children=null)]), TreeItem(id=5, parentId=1, name=总1, children=[TreeItem(id=6, parentId=5, name=总1/2, children=[TreeItem(id=2, parentId=6, name=李四, children=null)]), TreeItem(id=1, parentId=5, name=张三, children=null)])])

上面是我打印出来的数据，其实你们只要返回treeItem这个集合就可以了，这个数据结构符合Cascader级联选择器。

ElementUI组件Cascader级联选择器数据后台处理的相关教程结束。