如何在java中完全删除集合(包括文档子集合)

Question

我只是像下面这样修改了一些正式的示例片段

    static void deleteCollection(CollectionReference collection, int batchSize) {
    try {
        // retrieve a small batch of documents to avoid out-of-memory errors
        ApiFuture<QuerySnapshot> future = collection.limit(batchSize).get();
        int deleted = 0;
        // future.get() blocks on document retrieval
        List<QueryDocumentSnapshot> documents = future.get().getDocuments();
        for (QueryDocumentSnapshot document : documents) {

            //delete subcollections
            Iterable<CollectionReference> collections =
                    document.getReference().listCollections();
            for (CollectionReference collRef : collections) {
                deleteCollection(collRef, batchSize);
            }
            //delete document
            document.getReference().delete();
            ++deleted;
        }
        if (deleted >= batchSize) {
            // retrieve and delete another batch
            deleteCollection(collection, batchSize);
        }
    } catch (Exception e) {
        System.err.println("Error deleting collection : " + e.getMessage());
    }
}

但是这个代码对我不起作用。文档子集合保持原样。这里怎么了？谢谢你的回答

Answer 1

只是为某人分享正确的代码

private static void deleteCollection(CollectionReference collection, int batchSize) {
    try {
        // retrieve a small batch of documents to avoid out-of-memory errors
        ApiFuture<QuerySnapshot> future = collection.limit(batchSize).get();
        int deleted = 0;
        // future.get() blocks on document retrieval
        List<QueryDocumentSnapshot> documents = future.get().getDocuments();
        for (QueryDocumentSnapshot document : documents) {

            //delete document
            document.getReference().delete();
            ++deleted;
            //delete subcollections
            Iterable<CollectionReference> collections =
                    document.getReference().listCollections();
            for (CollectionReference collRef : collections) {
                deleteCollection(collRef, batchSize);
            }

        }
        if (deleted >= batchSize) {
            // retrieve and delete another batch
            deleteCollection(collection, batchSize);
        }
    } catch (Exception e) {
        System.err.println("Error deleting collection : " + e.getMessage());
    }
}