java web项目 树形菜单排序算法

本文原创: https://blog.csdn.net/u011625492/article/details/78459287

业务场景: 管理系统登陆后,需要将菜单按照树形结构来显示.如下所示

代码实现

package com.cn.cs.util;

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


import com.cn.cs.model.SiteResource;

public class TreeUtil {
    
    private List<SiteResource> nodes;
    
    public TreeUtil(List<SiteResource> nodes) {
        this.nodes=nodes;
    }
    /**
     * 创建树
     * @return
     */
    public List<TreeMessage> buildTree(){
        List<TreeMessage> list = new ArrayList<TreeMessage>();
　　　　　//获取最顶级菜单
        for (SiteResource node : nodes) {   
            if(node.getNodeCode().length()==2) {
                TreeMessage tm = new TreeMessage();
                tm.setId(Integer.parseInt(node.getId()));
                tm.setNodeIndex(Integer.parseInt(node.getNodeIndex().toString()));
                tm.setNodeCode(node.getNodeCode());
                tm.setText(node.getName());
                tm.setChecked(true);
                list.add(tm);
            }
        }  
        list = getSortChildren(list);
        for (TreeMessage node : list) {
           build(node); 
         }
        return list;
    } 
    
    
     /**
        * 构建权限树
　　　　　* 获取菜单中的所有子菜单,并添加到父菜单中
        */
   private void build(TreeMessage node){  
       List<TreeMessage> children = getChildren(node);  
       if (!children.isEmpty()) {  
             node.setChildren(children);
            
           for (TreeMessage child : children) {  
               build(child);  
           }  
       } 
   }  
   
  /*
   * 
  * @Description: TODO 获取子节点
  * @return
   */
  private List<TreeMessage> getChildren(TreeMessage node){  
      List<TreeMessage> children = new ArrayList<TreeMessage>();  
      String nodeCode = node.getNodeCode(); 
      for (SiteResource child : nodes) {  
          if (nodeCode.equals(child.getPcode())) {  
              TreeMessage tm = new TreeMessage();
              tm.setId(Integer.parseInt(child.getId()));
              tm.setNodeCode(child.getNodeCode());
              tm.setNodeIndex(Integer.parseInt(child.getNodeIndex().toString()));
              tm.setText(child.getName());
              tm.setChecked(true);
              Attributes attributes = new Attributes();
              attributes.setUrl(child.getUrl());
              tm.setAttributes(attributes);
              children.add(tm);  
          }  
      }  
      return getSortChildren(children);
  }  
    
    /* *
     * 
    * @Title: getChildren 
    * @Description: TODO 获取排序子节点
    * @param node
    * @return
     */
    private List<TreeMessage> getSortChildren(List<TreeMessage> children){
        ComparatorResource my = new ComparatorResource(); //这是一个自定义比较器,按照下标顺序排序
        Collections.sort(children,my) ; 
        return children;  
    }  
    

}