查询子id合集

创建实体类

@Datapublic 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);    }