java递归 处理权限管理菜单树或分类

1.数据库表设计

2.实体类设计

 package com.ieou.capsule.dto.SystemPermissions;

 import java.util.List;

 /**
  * 功能菜单类
  */
 public class SystemPermissionsTree {

     private String functionCode;//菜单码

     private String parentFunctionCode;//父级菜单码

     private String functionName;//菜单名

     private Boolean flag; // true:选中   false:未选中

     private List<SystemPermissionsTree> childrenList;

     public String getFunctionCode() {
         return functionCode;
     }

     public void setFunctionCode(String functionCode) {
         this.functionCode = functionCode;
     }

     public String getParentFunctionCode() {
         return parentFunctionCode;
     }

     public void setParentFunctionCode(String parentFunctionCode) {
         this.parentFunctionCode = parentFunctionCode;
     }

     public String getFunctionName() {
         return functionName;
     }

     public void setFunctionName(String functionName) {
         this.functionName = functionName;
     }

     public Boolean getFlag() {
         return flag;
     }

     public void setFlag(Boolean flag) {
         this.flag = flag;
     }

     public List<SystemPermissionsTree> getChildrenList() {
         return childrenList;
     }

     public void setChildrenList(List<SystemPermissionsTree> childrenList) {
         this.childrenList = childrenList;
     }
 }

3.递归工具类

 package com.ieou.capsule.util;

 import com.ieou.capsule.dto.SystemPermissions.SystemPermissionsTree;

 import java.util.ArrayList;
 import java.util.List;

 public class TreeUtil {
     /**
      * 作者：一沐枫一
      * 来源：CSDN
      * 原文：https://blog.csdn.net/gxgl8811/article/details/72803833
      * 版权声明：本文为博主原创文章，转载请附上博文链接！
      */

     public static List<SystemPermissionsTree> getTreeList(List<SystemPermissionsTree> entityList) {
         List<SystemPermissionsTree> resultList = new ArrayList<>();

         //获取顶层元素集合
         String parentCode;
         for (SystemPermissionsTree entity : entityList) {
             parentCode = entity.getParentFunctionCode();
             //顶层元素的parentCode==null或者为0
             if (parentCode == null || "0".equals(parentCode)) {
                 resultList.add(entity);
             }
         }

         //获取每个顶层元素的子数据集合
         for (SystemPermissionsTree entity : resultList) {
             entity.setChildrenList(getSubList(entity.getFunctionCode(), entityList));
         }

         return resultList;
     }

     /**
      * 获取子数据集合
      *
      * @param id
      * @param entityList
      * @return
      * @author jianda
      * @date 2017年5月29日
      */
     private static List<SystemPermissionsTree> getSubList(String id, List<SystemPermissionsTree> entityList) {
         List<SystemPermissionsTree> childList = new ArrayList<>();
         String parentId;

         //子集的直接子对象
         for (SystemPermissionsTree entity : entityList) {
             parentId = entity.getParentFunctionCode();
             if (id.equals(parentId)) {
                 childList.add(entity);
             }
         }

         //子集的间接子对象
         for (SystemPermissionsTree entity : childList) {
             entity.setChildrenList(getSubList(entity.getFunctionCode(), entityList));
         }

         //递归退出条件
         if (childList.size() == 0) {
             return null;
         }

         return childList;
     }

 }