Power BI中实时流数据集的空白报告

Question

我写了一个Java rest api，并包含了推URL来推送流数据。问题是，当创建报表时，它们为空白或为空！有什么我想念的吗？我是Power BI的业余爱好者。

public static void main(String args[]) throws IOException, InterruptedException 
{
    MongoClient mongo = new MongoClient("ip", 27017);
    String push_url = "https://api.powerbi.com/beta/950bde67-19db-467b- 
        9a41-f80b7cf24ecb/datasets/dde28014-bf2a-46b3-830a-881144a2aec/rows?
key="vQbtAll96T4lJ9OgYBK1MEB6z4IPMOzOyLzkPUM05%2Fzk%2B
1l1S2fezWEKdJA%3D%3D";

    DB db = mongo.getDB("test");
    DBCollection table = db.getCollection("collection");
    DBCursor cursor = table.find();
    while(cursor.hasNext()) {
        BasicDBObject document = new BasicDBObject();
        BasicDBObject header = (BasicDBObject) cursor.next().get("header");
        Object number = header.get("number");
        BasicDBObject data = (BasicDBObject) cursor.next().get("data");
        BasicDBList list = (BasicDBList) ((DBObject) data.get("transaction"));
        for (int i = 0; i < list.size(); i++) {
            BasicDBObject transaction = (BasicDBObject) list.get(i);
            Object transactionID = transaction.get("transactionID");
            document.put("number", number);
            document.put("transaction", transactionID);
            URL url = new URL(push_urls);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            OutputStreamWriter out = new OutputStreamWriter(conn.getOutputStream());
            out.write(String.valueOf(document));
            out.flush();
        }
    }
}