查询子id合集

创建实体类

@Data

public class Department {

private int id;

private int pid;

private String name;

public Department(int id, int pid, String name) {

this.id = id;

this.pid = pid;

this.name = name;

}

方法

//递归查询子部门---lists所有部门合集，set为id合集，

private static Set intset = new HashSet<>();

private static void getChiildrenDepartment(List lists, Set set) {

Set set1 = new HashSet<>();

for (Department depart : lists) {

for (Integer i : set) {

if (i.equals(new Integer(depart.getPid()))) {

set1.add(depart.getId());

intset.add(depart.getId());

getChiildrenDepartment(lists, set1);

}

}

}

}

//递归查询父部门---lists所有部门合集，set为id合集，topId为顶层id

private static void getParentDepartmnet(List lists, Set set, int topId){

Set set1 = new HashSet<>();

for (Department depart : lists) {

for (Integer i : set) {

if (i.equals(new Integer(depart.getId()))) {

set1.add(depart.getPid());

intset.add(depart.getPid());

}

if( depart.getPid() == topId){

continue;

}else {

getParentDepartmnet(lists, set1, topId);

}

}

}

}

测试

public static void main(String[] args) {

Department d1 = new Department(1, 0, "总部");

Department d2 = new Department(2, 1, "分部2");

Department d3 = new Department(3, 1, "分部3");

Department d4 = new Department(4, 1, "分部4");

Department d5 = new Department(5, 2, "分部2子部1");

Department d6 = new Department(6, 2, "分部2子部2");

Department d7 = new Department(7, 3, "分部3子部1");

List list = new ArrayList<>();

list.add(d1);

list.add(d2);

list.add(d3);

list.add(d4);

list.add(d5);

list.add(d6);

list.add(d7);

Set set = new HashSet<>();

set.add(7);

getChiildrenDepartment(list, set);

System.out.println(intset);

intset.addAll(set);

System.out.println(intset);

intset.clear();

getParentDepartmnet(list, set,0);

System.out.println(intset);

intset.addAll(set);

System.out.println(intset);

}