QJsonObject不能正常返回值。
json
{"response":{"header":{"resultCode":"0000","resultMsg":"OK"},"body":{"items":{"item":[{"baseDate":20190413,"baseTime":"0600","category":"PTY","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"REH","nx":55,"ny":127,"obsrValue":-998},{"baseDate":20190413,"baseTime":"0600","category":"RN1","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"T1H","nx":55,"ny":127,"obsrValue":6.3},{"baseDate":20190413,"baseTime":"0600","category":"UUU","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"VEC","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"VVV","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"WSD","nx":55,"ny":127,"obsrValue":0}]},"numOfRows":10,"pageNo":1,"totalCount":8}}}
代码
QJsonDocument jsonDoc = QJsonDocument::fromJson(reply->readAll());
QJsonObject jsonObj = jsonDoc.object();
QString status = jsonObj["resultMsg"].toString(); // empty
QJsonArray items = jsonObj["item"].toArray(); // null
我希望可以将OK存储在状态变量中,但其中不包含任何内容。
items变量存储空值。
答案 0 :(得分:1)
要理解,最好使用以下格式查看json:
{
"response": {
"header": {
"resultCode": "0000",
"resultMsg": "OK"
},
"body": {
"items": {
"item": [{
"baseDate": 20190413,
"baseTime": "0600",
"category": "PTY",
"nx": 55,
"ny": 127,
"obsrValue": 0
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "REH",
"nx": 55,
"ny": 127,
"obsrValue": -998
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "RN1",
"nx": 55,
"ny": 127,
"obsrValue": 0
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "T1H",
"nx": 55,
"ny": 127,
"obsrValue": 6.3
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "UUU",
"nx": 55,
"ny": 127,
"obsrValue": 0
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "VEC",
"nx": 55,
"ny": 127,
"obsrValue": 0
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "VVV",
"nx": 55,
"ny": 127,
"obsrValue": 0
}, {
"baseDate": 20190413,
"baseTime": "0600",
"category": "WSD",
"nx": 55,
"ny": 127,
"obsrValue": 0
}]
},
"numOfRows": 10,
"pageNo": 1,
"totalCount": 8
}
}
}
Json是一种格式,其中每个元素都有一个层次结构,也就是说要访问一个元素,您必须通过父级来进行操作。
在resultMsg的情况下,您必须访问response -> header-> resultMsg
。
在这种情况下,您必须访问response -> body-> items-> item
。
考虑到上述情况,解决方案是:
QJsonArray item_array;
QString status;
QJsonDocument jsonDoc = QJsonDocument::fromJson(reply->readAll());
QJsonObject jsonObj = jsonDoc.object();
if(jsonObj.contains("response")){
QJsonObject response_obj = jsonObj["response"].toObject();
if(response_obj.contains("header")){
QJsonObject header_obj = response_obj["header"].toObject();
if(header_obj.contains("resultMsg")){
status = header_obj["resultMsg"].toString();
}
}
if(response_obj.contains("body")){
QJsonObject body_obj = response_obj["body"].toObject();
if(body_obj.contains("items")){
QJsonObject items_obj = body_obj["items"].toObject();
if(items_obj.contains("item")){
item_array = items_obj["item"].toArray();
}
}
}
}
qDebug()<< "status:" << status;
qDebug()<< "item:" << item_array;
输出:
status: "OK"
item: QJsonArray([{"baseDate":20190413,"baseTime":"0600","category":"PTY","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"REH","nx":55,"ny":127,"obsrValue":-998},{"baseDate":20190413,"baseTime":"0600","category":"RN1","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"T1H","nx":55,"ny":127,"obsrValue":6.3},{"baseDate":20190413,"baseTime":"0600","category":"UUU","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"VEC","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"VVV","nx":55,"ny":127,"obsrValue":0},{"baseDate":20190413,"baseTime":"0600","category":"WSD","nx":55,"ny":127,"obsrValue":0}])