从json响应中读取数据 [英] Read data from json response
本文介绍了从json响应中读取数据的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试从JSON中读取一个项目的值。
例如：
{
findCompletedItemsResponse
{
ack：[
成功
]，
版本：[
1.13.0
] ，
timestamp：[
2016-06-02T16：07：36.736Z
]，
searchResult：[
{
@count：2，
item：[
{
itemId：[
172168793372
]，
标题：[
尼康D5000 12.3 MP数码单反相机（仅配备配件）
]，
globalId：[
EBAY-US
]，
primaryCategory：[
{
categoryId：[
31388
]，
categoryName：[
数码相机
]
}
] ，
galleryURL：[
http：\ / \ / thumbs1.ebaystatic.com\ / m\ / mlRCNAriHPzowbSV9Q7ZFAg\ / 140.jpg
]，
viewItemURL：[
http：\ / \ / www.ebay.com \ / itm\ / Nikon-D5000-12-3-MP-数码单反相机机身 - $
，
paymentMethod：[
PayPal
]，
autoPay：[
false
]，
邮政编码：[
02806
]，
location：[
Barrington，RI，美国
，
country：[
US
]，
shippingInfo：[
{
shippingServiceCost：[
{
@currencyId：USD，
__value __：0.0
}
]，
shippingType：[
免费
]，
shipToLocations：[
US
]，
expeditedShipping：[
true
]，
oneDayShippingAvailable：[
false
]，
处理时间：[
2
]
}
] ，
sellStatus：[
{
currentPrice：[
{
@currencyId：USD，
__value __：178.5
}
]，
convertedCurrentPrice：[
{
@currencyId：USD，
__value __：178.5
}
]，
bidCount ：[
13
]，
sellState：[
EndedWithSales
]
}
]，
listingInfo：[
{
bestOfferEnabled：[
false
]，
buyItNowAvailable：[
false
]，
startTime：[
$ 4
，
endTime：[
2016-04-25T18：45：54.000Z
]，
listingType：[
拍卖
]，
礼物：[
假
]
}
returnAccepted：[
false
]，
条件：[
{
conditionId：[
3000
]，
conditionDisplayName：[
使用
]
}
]，
isMultiVariationListing ：[
false
]，
topRatedListing：[
false
]
}，
{
itemId：[
172200026135
]，
title：[
Nikon D5000 12.3 MP数码单反相机（仅配备配件）
]，
globalId：[
EBAY-US
]，
primaryCategory [
{
categoryId：[
31388
]，
categoryName：[
数码相机
]
}
]，
galleryURL：[
http：\ / \ / thumbs4.ebaystatic.com\ / m\ / mlRCNAriHPzowbSV9Q7ZFAg\ / 140 .jpg
]，
viewItemURL：[
http：\ / \ / www.ebay.com\ / itm\ / Nikon-D5000-12-3 -MP-Di gital-SLR-Camera-Body-Only-Accessories-\ / 172200026135
]，
paymentMethod：[
PayPal
]，
自动付款：[
false
]，
邮政编码：[
02806
]，
位置：[
Barrington，RI，USA
]，
country：[
US
]，
shippingInfo：[
{
shippingServiceCost：[
{
@currencyId：USD，
__value __：0.0
}
]
shippingType：[
免费
]，
shipToLocations：[
US
]，
expeditedShipping：[
true
]，
oneDayShippingAvailable：[
false
]，
处理时间：[
2
]
}
]，
sellStatus：[
{
currentPrice [
{
@currencyId：USD，
__value __：119.49
}
]，
convertedCurrentPrice
{
@currencyId：USD，
__value __：119.49
}
]，
bidCount：[
2
]，
se l
listInfo：[
{
bestOfferEnabled：[
EndedWithSales
]
false
]，
buyItNowAvailable：[
false
]，
startTime：[
2016 -05-10T07：22：34.000Z
]，
endTime：[
\"ODIM-16T19：22：25.000Z
]，
listingType：[
拍卖
]，
礼物：[
假
]
}
] ，
returnsAccepted：[
false
]，
条件：[
{
conditionId：[
3000
]，
conditionDisplayName：[
使用
]
]，
isMultiVariationListing：[
false
]，
topRatedListing：[
false
]
}
]
}
]，
paginationOutput：[
{
pageNumber：[
1
]，
entriesPerPage：[
100
]，
totalPages：[
1
]，
totalEntries：[
2
]
}
]
}
]
}
我只想提取th的价格e在ebay上列出的项目。我猜这是 currentPrice 。
如何仅将价格的值提取到变量？
解决方案
这是可怕的JSON。谁设计这个数据根本不了解JSON。这个JSON严重过度使用了1元素数组和字符串值。大多数数组根本不属于，而JSON还有其他数据类型（布尔，整数等）。
无论如何，您可以使用Delphi的内置函数，在 JSON框架中解析此JSON，例如：
使用
System.JSON;
var
json：string;
obj：TJSONObject;
completedItems，sresults，items，status，price：TJSONArray;
I，J，K：整数;
currencyId，value：string;
begin
json：= ...; //< - 你的JSON字符串这里
obj：= TJSONObject.ParseJSONValue（json，0）as TJSONObject;
try
completedItems：= obj.Values ['findCompletedItemsResponse'] as TJSONArray;
for I：= 0 to completedItems.Count-1 do
begin
sresults：=（completedItems.Items [I] as TJSONObject）.Values ['searchResult'] as TJSONArray;
for J：= 0 to sresults.Count-1 do
begin
items：=（sresults.Items [J] as TJSONObject）.Values ['item'] as TJSONArray;
K：= 0 to items.Count-1 do
begin
status：=（items.Items [K] as TJSONObject）.Values ['sellStatus'] as TJSONArray;
price：=（（status.Items [0] as TJSONObject）.Values ['currentPrice']）作为TJSONArray;
currencyId：= price.Values ['@ currencyId']。
value：= price.Values ['__ value __']。
//根据需要使用价格值...
end;
结束
finally
obj.Free;
结束
结束
或者：
code>使用
System.JSON，System.JSON.Types;
var
json：string;
sreader：TStringReader;
jreader：TJsonTextReader;
inCurrentPrice：Boolean;
currencyId，value：string;
begin
json：= ...; //< - 你的JSON字符串这里
sreader：= TStringReader.Create（json）;
try
jreader：= TJsonTextReader.Create（sreader）;
try
inCurrentPrice：= False;
while jreader.Read do
begin
case jreader.TokenType
TJsonToken.PropertyName：begin
如果inCurrentPrice然后
begin
如果jreader .Value.AsString ='currencyId'然后开始
currencyId：= jreader.ReadAsString;
end
else if jreader.Value.AsString ='__value__'then begin
value：= jreader.ReadAsString;
结束
end
else if jreader.Value.AsString ='currentPrice'then
begin
currencyId：='';
value：='';
inCurrentPrice：= True;
结束
结束
TJsonToken.EndArray：begin
如果inCurrentPrice然后
begin
inCurrentPrice：= False;
//根据需要使用货币值...
end;
结束
结束
结束
finally
jreader.Free;
结束
finally
sreader.Free;
结束
结束
I am developing an application with Delphi 10 Seattle.
I am trying to read a value of an item from JSON.
For example :
{
"findCompletedItemsResponse":[
{
"ack":[
"Success"
],
"version":[
"1.13.0"
],
"timestamp":[
"2016-06-02T16:07:36.736Z"
],
"searchResult":[
{
"@count":"2",
"item":[
{
"itemId":[
"172168793372"
],
"title":[
"Nikon D5000 12.3 MP Digital SLR Camera (Body Only with Accessories)"
],
"globalId":[
"EBAY-US"
],
"primaryCategory":[
{
"categoryId":[
"31388"
],
"categoryName":[
"Digital Cameras"
]
}
],
"galleryURL":[
"http:\/\/thumbs1.ebaystatic.com\/m\/mlRCNAriHPzowbSV9Q7ZFAg\/140.jpg"
],
"viewItemURL":[
"http:\/\/www.ebay.com\/itm\/Nikon-D5000-12-3-MP-Digital-SLR-Camera-Body-Only-Accessories-\/172168793372"
],
"paymentMethod":[
"PayPal"
],
"autoPay":[
"false"
],
"postalCode":[
"02806"
],
"location":[
"Barrington,RI,USA"
],
"country":[
"US"
],
"shippingInfo":[
{
"shippingServiceCost":[
{
"@currencyId":"USD",
"__value__":"0.0"
}
],
"shippingType":[
"Free"
],
"shipToLocations":[
"US"
],
"expeditedShipping":[
"true"
],
"oneDayShippingAvailable":[
"false"
],
"handlingTime":[
"2"
]
}
],
"sellingStatus":[
{
"currentPrice":[
{
"@currencyId":"USD",
"__value__":"178.5"
}
],
"convertedCurrentPrice":[
{
"@currencyId":"USD",
"__value__":"178.5"
}
],
"bidCount":[
"13"
],
"sellingState":[
"EndedWithSales"
]
}
],
"listingInfo":[
{
"bestOfferEnabled":[
"false"
],
"buyItNowAvailable":[
"false"
],
"startTime":[
"2016-04-18T18:45:54.000Z"
],
"endTime":[
"2016-04-25T18:45:54.000Z"
],
"listingType":[
"Auction"
],
"gift":[
"false"
]
}
],
"returnsAccepted":[
"false"
],
"condition":[
{
"conditionId":[
"3000"
],
"conditionDisplayName":[
"Used"
]
}
],
"isMultiVariationListing":[
"false"
],
"topRatedListing":[
"false"
]
},
{
"itemId":[
"172200026135"
],
"title":[
"Nikon D5000 12.3 MP Digital SLR Camera (Body Only with Accessories)"
],
"globalId":[
"EBAY-US"
],
"primaryCategory":[
{
"categoryId":[
"31388"
],
"categoryName":[
"Digital Cameras"
]
}
],
"galleryURL":[
"http:\/\/thumbs4.ebaystatic.com\/m\/mlRCNAriHPzowbSV9Q7ZFAg\/140.jpg"
],
"viewItemURL":[
"http:\/\/www.ebay.com\/itm\/Nikon-D5000-12-3-MP-Digital-SLR-Camera-Body-Only-Accessories-\/172200026135"
],
"paymentMethod":[
"PayPal"
],
"autoPay":[
"false"
],
"postalCode":[
"02806"
],
"location":[
"Barrington,RI,USA"
],
"country":[
"US"
],
"shippingInfo":[
{
"shippingServiceCost":[
{
"@currencyId":"USD",
"__value__":"0.0"
}
],
"shippingType":[
"Free"
],
"shipToLocations":[
"US"
],
"expeditedShipping":[
"true"
],
"oneDayShippingAvailable":[
"false"
],
"handlingTime":[
"2"
]
}
],
"sellingStatus":[
{
"currentPrice":[
{
"@currencyId":"USD",
"__value__":"119.49"
}
],
"convertedCurrentPrice":[
{
"@currencyId":"USD",
"__value__":"119.49"
}
],
"bidCount":[
"2"
],
"sellingState":[
"EndedWithSales"
]
}
],
"listingInfo":[
{
"bestOfferEnabled":[
"false"
],
"buyItNowAvailable":[
"false"
],
"startTime":[
"2016-05-10T07:22:34.000Z"
],
"endTime":[
"2016-05-16T19:22:25.000Z"
],
"listingType":[
"Auction"
],
"gift":[
"false"
]
}
],
"returnsAccepted":[
"false"
],
"condition":[
{
"conditionId":[
"3000"
],
"conditionDisplayName":[
"Used"
]
}
],
"isMultiVariationListing":[
"false"
],
"topRatedListing":[
"false"
]
}
]
}
],
"paginationOutput":[
{
"pageNumber":[
"1"
],
"entriesPerPage":[
"100"
],
"totalPages":[
"1"
],
"totalEntries":[
"2"
]
}
]
}
]
}
I only want to extract the price of the listed item on ebay. Which is I guess the currentPrice.
How can I extract only the value of the price to a variable?
解决方案
This is horrible JSON. Whoever designed this data doesn't understand JSON at all. This JSON is grossly overusing 1-element arrays and string values. Most of the arrays do not belong at all, and JSON has other data types available (booleans, integers, etc).
In any case, you can use Delphi's built-in JSON framework to parse this JSON, eg:
uses
System.JSON;
var
json: string;
obj: TJSONObject;
completedItems, sresults, items, status, price: TJSONArray;
I, J, K: Integer;
currencyId, value: string;
begin
json := ...; // <-- your JSON string here
obj := TJSONObject.ParseJSONValue(json, 0) as TJSONObject;
try
completedItems := obj.Values['findCompletedItemsResponse'] as TJSONArray;
for I := 0 to completedItems.Count-1 do
begin
sresults := (completedItems.Items[I] as TJSONObject).Values['searchResult'] as TJSONArray;
for J := 0 to sresults.Count-1 do
begin
items := (sresults.Items[J] as TJSONObject).Values['item'] as TJSONArray;
for K := 0 to items.Count-1 do
begin
status := (items.Items[K] as TJSONObject).Values['sellingStatus'] as TJSONArray;
price := ((status.Items[0] as TJSONObject).Values['currentPrice']) as TJSONArray;
currencyId := price.Values['@currencyId'].Value;
value := price.Values['__value__'].Value;
// use price values as needed...
end;
end;
finally
obj.Free;
end;
end;
Alternatively:
uses
System.JSON, System.JSON.Types;
var
json: string;
sreader: TStringReader;
jreader: TJsonTextReader;
inCurrentPrice: Boolean;
currencyId, value: string;
begin
json := ...; // <-- your JSON string here
sreader := TStringReader.Create(json);
try
jreader := TJsonTextReader.Create(sreader);
try
inCurrentPrice := False;
while jreader.Read do
begin
case jreader.TokenType of
TJsonToken.PropertyName: begin
if inCurrentPrice then
begin
if jreader.Value.AsString = 'currencyId' then begin
currencyId := jreader.ReadAsString;
end
else if jreader.Value.AsString = '__value__' then begin
value := jreader.ReadAsString;
end;
end
else if jreader.Value.AsString = 'currentPrice' then
begin
currencyId := '';
value := '';
inCurrentPrice := True;
end;
end;
TJsonToken.EndArray: begin
if inCurrentPrice then
begin
inCurrentPrice := False;
// use currency values as needed...
end;
end;
end;
end;
finally
jreader.Free;
end;
finally
sreader.Free;
end;
end;
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