list集合数据转换tree树型结构（通用方法）含使用示例

/**
	 * 获取子级
	 * 
	 * @param fieldParentId 父级ID字段
	 * @param fieldCurId    当前ID字段
	 * @param data          集合数据
	 * @param curId         当前ID值
	 * @return children 集合
	 */
	private static List<Map<String, Object>> getChildren(String fieldParentId, String fieldCurId,
			List<Map<String, Object>> data, String curId) {
		/**
		 * 1.对数据校验处理
		 */
		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
		if (data == null || data.size() == 0) {
			return list;
		}

		/**
		 * 2.遍历匹配父子级关系数据
		 */
		for (Map<String, Object> dataMap : data) {
			if (curId.equals(dataMap.get(fieldParentId).toString())) {
				dataMap.put("children",
						getChildren(fieldParentId, fieldCurId, data, dataMap.get(fieldCurId).toString()));
				list.add(dataMap);
			}
		}
		/**
		 * 3.返回处理后的结果对象
		 */
		return list;
	}

测试方法（调用示例）： 

public static void main(String[] args) {
		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
		list.add(new HashMap<String, Object>() {
			{
				put("parent_id", "-1");
				put("id", "1");
				put("name", "省1");
			}
		});
		list.add(new HashMap<String, Object>() {
			{
				put("parent_id", "-1");
				put("id", "2");
				put("name", "省2");
			}
		});
		list.add(new HashMap<String, Object>() {
			{
				put("parent_id", "2");
				put("id", "22");
				put("name", "省2市2");
			}
		});
		for (Map<String, Object> map : list) {
			map.put("children", getChildren("parent_id", "id", list, map.get("id").toString()));
		}

		for (Map<String, Object> map : list) {
			System.out.println(map);
		}
	}

输出结果：