java通过key-list和对应value更新当前对象

当前有一个复杂对象,类似json,现在要对当前对象进行更新(已有的key更新,未有的key插入)

//递归更新一个json对象,原对象若没有则插入key,精妙!
    @SuppressWarnings("unchecked")
    Object setObjectRecursive(Object current, final List<String> paths,
                              int index, final Object value) {

        // 如果是已经超出path,我们就返回value即可,作为最底层叶子节点
        boolean isLastIndex = index == paths.size();
        if (isLastIndex) {
            return value;
        }

        String path = paths.get(index).trim();
        boolean isNeedMap = isPathMap(path);
        if (isNeedMap) {
            Map<String, Object> mapping;

            // 当前不是map,因此全部替换为map,并返回新建的map对象
            boolean isCurrentMap = current instanceof Map;
            if (!isCurrentMap) {
                mapping = new HashMap<String, Object>();
                mapping.put(
                        path,
                        buildObject(paths.subList(index + 1, paths.size()),
                                value));
                return mapping;
            }

            // 当前是map,但是没有对应的key,也就是我们需要新建对象插入该map,并返回该map
            mapping = ((Map<String, Object>) current);
            boolean hasSameKey = mapping.containsKey(path);
            if (!hasSameKey) {
                mapping.put(path,buildObject(paths.subList(index + 1, paths.size()),
                                value));
                return mapping;
            }

            // 当前是map,而且还竟然存在这个值,好吧,继续递归遍历
            current = mapping.get(path);
            mapping.put(path, setObjectRecursive(current, paths, index + 1, value));
            return mapping;
        }

        boolean isNeedList = isPathList(path);
        if (isNeedList) {
            List<Object> lists;
            int listIndexer = getIndex(path);

            // 当前是list,直接新建并返回即可
            boolean isCurrentList = current instanceof List;
            if (!isCurrentList) {
                lists = expand(new ArrayList<Object>(), listIndexer + 1);
                lists.set(
                        listIndexer,
                        buildObject(paths.subList(index + 1, paths.size()),
                                value));
                return lists;
            }

            // 当前是list,但是对应的indexer是没有具体的值,也就是我们新建对象然后插入到该list,并返回该List
            lists = (List<Object>) current;
            lists = expand(lists, listIndexer + 1);

            boolean hasSameIndex = lists.get(listIndexer) != null;
            if (!hasSameIndex) {
                lists.set(
                        listIndexer,
                        buildObject(paths.subList(index + 1, paths.size()),
                                value));
                return lists;
            }

            // 当前是list,并且存在对应的index,没有办法继续递归寻找
            current = lists.get(listIndexer);
            lists.set(listIndexer,
                    setObjectRecursive(current, paths, index + 1, value));
            return lists;
        }

        throw DataMException.asDataMException("该异常代表系统编程错误, 请联系DataX开发团队");
    }


 //根据key的类型来选择获取value的方式
    private boolean isPathMap(final String path) {
        return StringUtils.isNotBlank(path) && !isPathList(path);
    }

    private boolean isPathList(final String path) {
        return path.contains("[") && path.contains("]");
    }
原文地址:https://www.cnblogs.com/wangbin2188/p/14188511.html