java - 从多个 QuerySpec AWS Dynamodb 创建大型 JSON 响应

Question

我使用 QuerySpec 有多个查询，因此有多个 ItemCollection:

            Table table4 = dynamoDB.getTable("MyTable"); 
            QuerySpec spec4 = new QuerySpec()
                    .withKeyConditionExpression("id = :v_id")
                    .withValueMap(new ValueMap()
                    .withString(":v_id", SAFETY_CHAPTERS_UUIDS.get(i)));
            ItemCollection<QueryOutcome> items4 = table4.query(spec4);
            Iterator<Item> iterator4 = items4.iterator();
            Item itemsQuizzChapters = null;

我正在尝试找到一种方法来从这 4 个查询构建一个大的 JSON 响应。我如何将 itemCollection 添加到 JSON 对象或对象中，以便我可以使用所有这些对象创建一个大对象？

Answer 1

//import aws-java-sdk-bundle-1.11.85.jar, json-simple-1.1.jar and jackson-all-1.9.9.jar
public JSONObject getItemDynamoDB(String tableName, String primaryKey,String primaryKeyValue) {
       Table index = dynamoDB.getTable(tableName);
        QuerySpec querySpec = new QuerySpec().withKeyConditionExpression("#primaryKey = :value1")
        .withNameMap(new NameMap().with("#primaryKey", primaryKey))
        .withValueMap(new ValueMap().withString(":value1", primaryKeyValue));
        ItemCollection<QueryOutcome> items = index.query(querySpec);
       Iterator<Item> itemIterator = items.iterator();
        JSONObject jsonObject = null;
        try {
        Object obj = jsonParser.parse(itemIterator.next().toJSONPretty());
        jsonObject = (JSONObject) obj;

    } catch (ParseException e) {
        e.printStackTrace();
    }
        return jsonObject;
}
//call the function multiple time to get big JSON

public JSONArray concatenateMultipleItem(){
    JSONArray jsonArray = new JSONArray() ;
    jsonArray.add(getItemDynamoDB("TableName", "primaryKey", "1"));
    jsonArray.add(getItemDynamoDB("TableName2", "primaryKey2", "2"));   
    System.out.println(jsonArray);
    return jsonArray;
}

reference