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;
    }


}