java树结构工具类TreeBuilder和TreeUtil

package cloud.simple.service.util;

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

import cloud.simple.service.dto.TreeNode;

public class TreeBuilder {
  
    /** 
     * 使用递归方法建树 
     * @param treeNodes 
     * @return 
     */  
    public static List buildByRecursive(List treeNodes) {  
        List trees = new ArrayList();  
        for (TreeNode treeNode : treeNodes) {  
           System.err.println(treeNode);
            if ("0".equals(treeNode.getParentId())) {  
                trees.add(findChildren(treeNode,treeNodes, 0));  
            }  
        }  
        return trees;  
    }  
  
    /** 
     * 递归查找子节点 
     * @param treeNodes 
     * @return 
     */  
    public static TreeNode findChildren(TreeNode treeNode,List treeNodes, int root) {  
       treeNode.put("selected", false);
       treeNode.put("level", root);
        for (TreeNode it : treeNodes) {  
            if(treeNode.getId().equals(it.getParentId())) {  
                if (treeNode.getChildren() == null) {  
                    treeNode.setChildren(new ArrayList());  
                }  
                treeNode.getChildren().add(findChildren(it,treeNodes, root+1));  
            }  
        }  
        return treeNode;  
    }
    
   /* public static void main(String[] args) {
       TreeNode treeNode1 = new TreeNode("1","广州","0");  
        TreeNode treeNode2 = new TreeNode("2","深圳","0");  
  
        TreeNode treeNode3 = new TreeNode("3","天河区","1");  
        TreeNode treeNode4 = new TreeNode("4","越秀区","2");  
        TreeNode treeNode5 = new TreeNode("5","黄埔区",treeNode1);  
        TreeNode treeNode6 = new TreeNode("6","石牌",treeNode3);  
        TreeNode treeNode7 = new TreeNode("7","百脑汇",treeNode6);  
  
  
        TreeNode treeNode8 = new TreeNode("8","南山区",treeNode2);  
        TreeNode treeNode9 = new TreeNode("9","宝安区",treeNode2);  
        TreeNode treeNode10 = new TreeNode("10","科技园",treeNode8);  
  
  
        List list = new ArrayList();  
  
        list.add(treeNode1);  
        list.add(treeNode2);  
        list.add(treeNode3);  
        list.add(treeNode4);  
        list.add(treeNode5);  
        list.add(treeNode6);  
        list.add(treeNode7);  
        list.add(treeNode8);  
        list.add(treeNode9);  
        list.add(treeNode10);  
  
        List trees_ = TreeBuilder.buildByRecursive(list);  
        
        System.out.println(trees_);
    }*/
}

==========================================

package cloud.simple.service.util;

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

import org.apache.commons.collections.CollectionUtils;

import cloud.simple.service.dto.TreeNode;
import cloud.simple.service.model.SysAdminMenu;
import cloud.simple.service.model.SysAdminRule;

/**
 * 树工具类
 * @author leo
 *
 */
public class TreeUtil {
   /**
     * 将数据集转换成Tree（真正的Tree结构）
     * @param array $list 要转换的数据集
     * @param string $root 返回的根节点ID
     * @return List
     */
   public static List listMenuToTree(List list,Integer rootId) {
      //创建tree
      List tree = new ArrayList();  
      if (CollectionUtils.isNotEmpty(list)) {
         for (SysAdminMenu menu : list) {
            Integer pid = menu.getPid();
            if(pid == null || pid.equals(rootId)) {
               TreeNode treeNode = new TreeNode(menu.getId().toString(), menu.getTitle(),"0");
               treeNode.put("url", menu.getUrl());
               treeNode.put("menu_type", menu.getMenuType());
               treeNode.put("sort", menu.getSort());
               treeNode.put("status", menu.getStatus());
               treeNode.put("rule_id", menu.getRuleId());
               treeNode.put("module", menu.getModule());
               treeNode.put("module", menu.getModule());
               treeNode.put("menu", menu.getMenu());
               tree.add(treeNode);
            } else {
               TreeNode treeNode = new TreeNode(menu.getId().toString(), menu.getTitle(),pid.toString());
               treeNode.put("url", menu.getUrl());
               treeNode.put("menu_type", menu.getMenuType());
               treeNode.put("sort", menu.getSort());
               treeNode.put("status", menu.getStatus());
               treeNode.put("rule_id", menu.getRuleId());
               treeNode.put("module", menu.getModule());
               treeNode.put("module", menu.getModule());
               treeNode.put("menu", menu.getMenu());
               tree.add(treeNode);
            }
         }
      }
      return TreeBuilder.buildByRecursive(tree);
   }
   
   /**
     * 将数据集转换成Tree（真正的Tree结构）
     * @param array $list 要转换的数据集
     * @param string $root 返回的根节点ID
     * @return List
     */
   public static List listRuleToTree(List list,Integer rootId) {
      //创建tree
      List tree = new ArrayList();  
      if (CollectionUtils.isNotEmpty(list)) {
         for (SysAdminRule rule : list) {
            Integer pid = rule.getPid();
            if(pid == null || pid.equals(rootId)) {
               TreeNode treeNode = new TreeNode(rule.getId().toString(), rule.getTitle(),"0");
               tree.add(treeNode);
            } else {
               TreeNode treeNode = new TreeNode(rule.getId().toString(), rule.getTitle(),pid.toString());
               tree.add(treeNode);
            }
         }
      }
      return TreeBuilder.buildByRecursive(tree);
   }
}
=================

package cloud.simple.service.model;

import java.util.List;

import javax.persistence.Column;
import javax.persistence.Table;
import javax.persistence.Transient;

import cloud.simple.service.base.BaseEntity;

@Table(name = "`sys_admin_menu`")
public class SysAdminMenu  extends BaseEntity {
   private static final long serialVersionUID = 6521017462166057129L;


    /**
     * 上级菜单ID
     */
    @Column(name = "`pid`")
    private Integer pid;

    /**
     * 菜单名称
     */
    @Column(name = "`title`")
    private String title;

    /**
     * 链接地址
     */
    @Column(name = "`url`")
    private String url;

    /**
     * 图标
     */
    @Column(name = "`icon`")
    private String icon;

    /**
     * 菜单类型
     */
    @Column(name = "`menu_type`")
    //@JSONField(name="menu_type")  
    private Byte menuType;

    /**
     * 排序（同级有效）
     */
    @Column(name = "`sort`")
    private Byte sort;

    /**
     * 状态
     */
    @Column(name = "`status`")
    private Byte status;

    /**
     * 权限id
     */
    @Column(name = "`rule_id`")
    //@JSONField(name="rule_id") 
    private Integer ruleId;
    
    @Column(name = "`rule_name`")
    private String ruleName;

    @Column(name = "`module`")
    private String module;

    /**
     * 三级菜单吗
     */
    @Column(name = "`menu`")
    private String menu;
    
    /**
     * 子菜单 
     */
    @Transient
    private List child;
    /**
     * 是否选中
     */
    @Transient
    private Boolean selected = false;
    /**
     * 级别
     */
    @Transient
    private Integer level;
    
    /**
     * 全名
     */
    @Transient
    private String fullName;
    
    /**
     * 关键权限
     */
    @Transient
    private SysAdminRule rule;
    
    /**
     * 获取上级菜单ID
     *
     * @return pid - 上级菜单ID
     */
    public Integer getPid() {
        return pid;
    }

    /**
     * 设置上级菜单ID
     *
     * @param pid 上级菜单ID
     */
    public void setPid(Integer pid) {
        this.pid = pid;
    }

    /**
     * 获取菜单名称
     *
     * @return title - 菜单名称
     */
    public String getTitle() {
        return title;
    }

    /**
     * 设置菜单名称
     *
     * @param title 菜单名称
     */
    public void setTitle(String title) {
        this.title = title;
    }

    /**
     * 获取链接地址
     *
     * @return url - 链接地址
     */
    public String getUrl() {
        return url;
    }

    /**
     * 设置链接地址
     *
     * @param url 链接地址
     */
    public void setUrl(String url) {
        this.url = url;
    }

    /**
     * 获取图标
     *
     * @return icon - 图标
     */
    public String getIcon() {
        return icon;
    }

    /**
     * 设置图标
     *
     * @param icon 图标
     */
    public void setIcon(String icon) {
        this.icon = icon;
    }

    /**
     * 获取菜单类型
     *
     * @return menu_type - 菜单类型
     */
    public Byte getMenuType() {
        return menuType;
    }

    /**
     * 设置菜单类型
     *
     * @param menuType 菜单类型
     */
    public void setMenuType(Byte menuType) {
        this.menuType = menuType;
    }

    /**
     * 获取排序（同级有效）
     *
     * @return sort - 排序（同级有效）
     */
    public Byte getSort() {
        return sort;
    }

    /**
     * 设置排序（同级有效）
     *
     * @param sort 排序（同级有效）
     */
    public void setSort(Byte sort) {
        this.sort = sort;
    }

    /**
     * 获取状态
     *
     * @return status - 状态
     */
    public Byte getStatus() {
        return status;
    }

    /**
     * 设置状态
     *
     * @param status 状态
     */
    public void setStatus(Byte status) {
        this.status = status;
    }

    /**
     * 获取权限id
     *
     * @return rule_id - 权限id
     */
    public Integer getRuleId() {
        return ruleId;
    }

    /**
     * 设置权限id
     *
     * @param ruleId 权限id
     */
    public void setRuleId(Integer ruleId) {
        this.ruleId = ruleId;
    }

    /**
     * @return module
     */
    public String getModule() {
        return module;
    }

    /**
     * @param module
     */
    public void setModule(String module) {
        this.module = module;
    }

    /**
     * 获取三级菜单吗
     *
     * @return menu - 三级菜单吗
     */
    public String getMenu() {
        return menu;
    }

    /**
     * 设置三级菜单吗
     *
     * @param menu 三级菜单吗
     */
    public void setMenu(String menu) {
        this.menu = menu;
    }

   public List getChild() {
      return child;
   }

   public void setChild(List child) {
      this.child = child;
   }

   public Boolean getSelected() {
      return selected;
   }

   public void setSelected(Boolean selected) {
      this.selected = selected;
   }

   public Integer getLevel() {
      return level;
   }

   public void setLevel(Integer level) {
      this.level = level;
   }

   public String getFullName() {
      return fullName;
   }

   public void setFullName(String fullName) {
      this.fullName = fullName;
   }

   public SysAdminRule getRule() {
      return rule;
   }

   public void setRule(SysAdminRule rule) {
      this.rule = rule;
   }

   public String getRuleName() {
      return ruleName;
   }

   public void setRuleName(String ruleName) {
      this.ruleName = ruleName;
   }
   
   
}