一.举个栗子
1.menu实体类
package com.dafy.insureagent.bean;
public class Menu {
private String id;
private String name;
private String pid;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
@Override
public String toString() {
return "Menu [id=" + id + ", name=" + name + ", pid=" + pid + "]";
}
}
2.测试类
package com.dafy.insureagent.bean;
import java.util.ArrayList;
import java.util.List;
public class MenuRecursion {
//子节点
static List<Menu> childMenu = new ArrayList<Menu>();
/**
* 获取某个父节点下面的所有子节点
* @param menuList
* @param pid
* @return
*/
public static List<Menu> treeMenuList(List<Menu> menuList, int pid) {
for (Menu mu : menuList) {
//遍历出父id等于参数的id，add进子节点集合
if (Integer.valueOf(mu.getPid()) == pid) {
//递归遍历下一级
treeMenuList(menuList, Integer.valueOf(mu.getId()));
childMenu.add(mu);
}
}
return childMenu;
}
public static void main(String args[]) {
List<Menu> menuList = new ArrayList<Menu>();
Menu mu = new Menu();
mu.setId("1");
mu.setName("目录");
mu.setPid("0");
Menu mu1 = new Menu();
mu1.setId("2");
mu1.setName("目录1");
mu1.setPid("1");
Menu mu2 = new Menu();
mu2.setId("3");
mu2.setName("目录1.1");
mu2.setPid("2");
Menu mu3 = new Menu();
mu3.setId("4");
mu3.setName("目录1.2");
mu3.setPid("2");
Menu mu4 = new Menu();
mu4.setId("5");
mu4.setName("目录2");
mu4.setPid("1");
Menu mu5 = new Menu();
mu5.setId("6");
mu5.setName("目录2.1");
mu5.setPid("5");
Menu mu6 = new Menu();
mu6.setId("7");
mu6.setName("目录2.2");
mu6.setPid("5");
Menu mu7 = new Menu();
mu7.setId("8");
mu7.setName("目录2.2.1");
mu7.setPid("7");
menuList.add(mu);
menuList.add(mu1);
menuList.add(mu2);
menuList.add(mu3);
menuList.add(mu4);
menuList.add(mu5);
menuList.add(mu6);
menuList.add(mu7);
List<Menu> childList = treeMenuList(menuList, 1);
for (Menu m : childList) {
System.out.println(m.getId() + " " + m.getName());
}
}
}
3.控制台结果(注:本身节点不会获取)：
3 目录1.1
4 目录1.2
2 目录1
6 目录2.1
8 目录2.2.1
7 目录2.2
5 目录2
方便博主学习回忆
前面转载 https://blog.csdn.net/u010825931/article/details/79925719
如果想查A车间下面的最底层工位
再次遍历childlist是否是别人的父级，如果是，就不是最底层的
List<Menu> childList = treeMenuList(List, pid);
List<String > outList = new ArrayList<>();
childList.forEach(data->{
List<Menu> modelList=List.stream().filter(fData->fData.getPid().equals(data.getId())).collect(Collectors.toList());
if(modelList.size()==0){
outList.add(data.getId());
}
});