java将list转化成树

项目中需要传递组织机构数据，因为要校验上级站点是否存在（存在才能插入，除非根节点），然后就有了这个代码

 /**
     * 双重for循环方法转换成树形结构
     * @param zCompanyBeanList
     * @return
     */
    public static List<ZCompanyBean> buildTreeCompany(List<ZCompanyBean> zCompanyBeanList) {
        List<ZCompanyBean> result = new LinkedList<>();
        for (ZCompanyBean zCompanyBean : zCompanyBeanList) {
            if (StringUtils.isEmpty(zCompanyBean.getParent_id())) {
                result.add(zCompanyBean);
            }
            for (ZCompanyBean child : zCompanyBeanList) {
                if (child.getParent_id().equals(zCompanyBean.getCode())) {
                    List<ZCompanyBean> children = zCompanyBean.getChildren();
                    if (children == null) {
                        children = new LinkedList<>();
                        zCompanyBean.setChildren(children);
                    }
                    children.add(child);
                }
            }
        }
        return result;
    }
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其中实体类如下

@Data
public class ZCompanyBean {
    /**
     * 部门编码
     */
    private String code;
    /**
     * 上级部门
     */
    private String parent_id;
    /**
     * 部门name
     */
    private String name;
    private String remark;
    /**
     * 部门状态0：正常 1：删除  3：停职  4离职   5 退休
     */
    private String is_enable;
    private String oOrgCode;
    /**
     * 层级（用于批量传）
     */
    private int level;

    private List<ZCompanyBean> children;
}
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转化成一个树后还需要使用广度遍历，这样可以把一个层级的批量传过去
定义个level属性（层级）

 /**
     * 广度遍历层级（公司）
     * @param zCompanyBeanList
     */
    public static void spanForLevelCompany(List<ZCompanyBean> zCompanyBeanList){
        Queue<ZCompanyBean> queue = new LinkedList<>();
        for (ZCompanyBean zCompanyBean:zCompanyBeanList) {
            int level = 0;
            zCompanyBean.setLevel(level);
            queue.add(zCompanyBean);
            ZCompanyBean tree ;
            tree = queue.poll();
            while (null != tree) {
                if(null!=tree.getChildren()) {
                    for (ZCompanyBean tr : tree.getChildren()) {
                        tr.setLevel(tree.getLevel()+1);
                        queue.offer(tr);
                    }
                }
                tree = queue.poll();
            }
        }
    }
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最后是main方法

//构建树
            List<ZCompanyBean> zCompanyTreeList = TreeUtils.buildTreeCompany(zCompanyBeanList);
            //广度遍历层级（公司）
            TreeUtils.spanForLevelCompany(zCompanyTreeList);
            Map<Integer,List<Map<String, Object>>> map = new HashMap<>(10);
            //将传的数据分层级
            getLevelMap(zCompanyTreeList,map);
            for(int i=0;i<map.size();i++){
                List<Map<String, Object>> companyLevelList = map.get(i);
                List<List<Map<String, Object>>> parts = Lists.partition(companyLevelList, maxPostSize);
                for (List<Map<String, Object>> part:parts) {
                	***post传递参数***
                }
            }
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附录getLevelMap方法

public void getLevelMap(List<ZCompanyBean> result,Map<Integer,List<Map<String, Object>>> map){
        List<Map<String, Object>> list = null;
        for (ZCompanyBean zCompanyBean:result) {
            Map<String, Object> param = new HashMap<>(10);
            param.put("name", zCompanyBean.getName() + "");
            param.put("department_id", zCompanyBean.getDepartment_id() + "");
            param.put("code", zCompanyBean.getCode() + "");
            String parentId = zCompanyBean.getParent_id() + "";
            param.put("parent_id", parentId);
            param.put("level", zCompanyBean.getLevel());
            param.put("is_enable", zCompanyBean.getIs_enable());
            int level = zCompanyBean.getLevel();
            if(map.containsKey(level)){
                list = map.get(level);
            }else{
                list = new LinkedList<>();
            }
            list.add(param);
            map.put(level,list);
            if(null!=zCompanyBean.getChildren()){
                getLevelMap(zCompanyBean.getChildren(),map);
            }
        }
    }
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