使用jackson将JSON字符串转成List集合

public class MenuUtil {
	public static ListsMenuRequest changeMenuStringToListsMenuRequest(String menuString) {
		ListsMenuRequest listsMenuRequest = new ListsMenuRequest();
		try {
			ObjectMapper om = new ObjectMapper();
			JsonNode rootNode = om.readTree(menuString);
			listsMenuRequest.setMenuRequests(parserArray(rootNode));
			return listsMenuRequest;
		} catch (JsonParseException e) {
			throw new RuntimeException("解析json错误," + menuString, e);
		} catch (IOException e) {
			//it never happen
			return null;
		}
	}

	private static List<MenuRequest> parserArray(JsonNode jsonNode) {
		if (!jsonNode.isArray()) {
			throw new RuntimeException("json对象不是数组类型");
		}
		List<MenuRequest> result = new ArrayList<MenuRequest>();
		for (JsonNode node : jsonNode) {
			result.add(parserSingle(node));
		}
		return result;
	}

	private static MenuRequest parserSingle(JsonNode node) {
		String name = node.get("name").asText();
		if (!node.has("type")) {
			GroupMenuRequest result = new GroupMenuRequest();
			result.setName(name);
			List leafMenuRequest = parserArray(node.get("children"));
			result.setChildrens(((List<LeafMenuRequest>) leafMenuRequest));
			return result;
		}
		String type = node.get("type").asText();
		String value = node.get("value").asText();
		if (type.equals("VIEW")) {
			ViewMenuRequest result = new ViewMenuRequest();
			result.setName(name);
			result.setUrl(value);
			return result;
		}
		if (type.equals("CLICK")) {
			ClickMenuRequest result = new ClickMenuRequest();
			result.setName(name);
			result.setKey(value);
			return result;
		}
		throw new RuntimeException("不能识别的类型: " + type);
	}
}