我正在使用Delphi 10 Seattle开发应用程序。
我正在尝试从JSON中读取项目的值。
例如：
{
"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"
]
}
]
}
]
}
我只想在易趣上提取所列物品的价格。我猜是currentPrice。
如何仅将价格的值提取到变量？
答案 0 :(得分：4)
这是可怕的JSON。设计这些数据的人根本不了解JSON。这个JSON严重过度使用1元素数组和字符串值。大多数数组根本不属于，JSON还有其他可用的数据类型（布尔值，整数等）。
无论如何，你可以使用Delphi的内置JSON framework来解析这个JSON，例如：
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;
可替换地：
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;
答案 1 :(得分：2)
您可以使用此类工具为此JSON生成信封。
http://www.pgeorgiev.com/?p=1832
代码如下所示：
unit Test1;
// *************************************************
// Generated By: JsonToDelphiClass - 0.65
// Project link: https://github.com/PKGeorgiev/Delphi-JsonToDelphiClass
// Generated On: 2016-06-02 17:46:09
// *************************************************
// Created By : Petar Georgiev - 2014
// WebSite : http://pgeorgiev.com
// *************************************************
interface
uses Generics.Collections, Rest.Json;
type
TConditionClass = class
private
FConditionDisplayName: TArray<String>;
FConditionId: TArray<String>;
public
property conditionDisplayName: TArray<String> read FConditionDisplayName write FConditionDisplayName;
property conditionId: TArray<String> read FConditionId write FConditionId;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TConditionClass;
end;
TListingInfoClass = class
private
FBestOfferEnabled: TArray<String>;
FBuyItNowAvailable: TArray<String>;
FEndTime: TArray<String>;
FGift: TArray<String>;
FListingType: TArray<String>;
FStartTime: TArray<String>;
public
property bestOfferEnabled: TArray<String> read FBestOfferEnabled write FBestOfferEnabled;
property buyItNowAvailable: TArray<String> read FBuyItNowAvailable write FBuyItNowAvailable;
property endTime: TArray<String> read FEndTime write FEndTime;
property gift: TArray<String> read FGift write FGift;
property listingType: TArray<String> read FListingType write FListingType;
property startTime: TArray<String> read FStartTime write FStartTime;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TListingInfoClass;
end;
TConvertedCurrentPriceClass = class
private
FAcurrencyId: String;
F__value__: String;
public
property AcurrencyId: String read FAcurrencyId write FAcurrencyId;
property __value__: String read F__value__ write F__value__;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TConvertedCurrentPriceClass;
end;
TCurrentPriceClass = class
private
FAcurrencyId: String;
F__value__: String;
public
property AcurrencyId: String read FAcurrencyId write FAcurrencyId;
property __value__: String read F__value__ write F__value__;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TCurrentPriceClass;
end;
TSellingStatusClass = class
private
FBidCount: TArray<String>;
FConvertedCurrentPrice: TArray<TConvertedCurrentPriceClass>;
FCurrentPrice: TArray<TCurrentPriceClass>;
FSellingState: TArray<String>;
public
property bidCount: TArray<String> read FBidCount write FBidCount;
property convertedCurrentPrice: TArray<TConvertedCurrentPriceClass> read FConvertedCurrentPrice write FConvertedCurrentPrice;
property currentPrice: TArray<TCurrentPriceClass> read FCurrentPrice write FCurrentPrice;
property sellingState: TArray<String> read FSellingState write FSellingState;
destructor Destroy; override;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TSellingStatusClass;
end;
TShippingInfoClass = class
private
FExpeditedShipping: TArray<String>;
FHandlingTime: TArray<String>;
FOneDayShippingAvailable: TArray<String>;
FShipToLocations: TArray<String>;
FShippingType: TArray<String>;
public
property expeditedShipping: TArray<String> read FExpeditedShipping write FExpeditedShipping;
property handlingTime: TArray<String> read FHandlingTime write FHandlingTime;
property oneDayShippingAvailable: TArray<String> read FOneDayShippingAvailable write FOneDayShippingAvailable;
property shipToLocations: TArray<String> read FShipToLocations write FShipToLocations;
property shippingType: TArray<String> read FShippingType write FShippingType;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TShippingInfoClass;
end;
TProductIdClass = class
private
FAtype: String;
F__value__: String;
public
property Atype: String read FAtype write FAtype;
property __value__: String read F__value__ write F__value__;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TProductIdClass;
end;
TPrimaryCategoryClass = class
private
FCategoryId: TArray<String>;
FCategoryName: TArray<String>;
public
property categoryId: TArray<String> read FCategoryId write FCategoryId;
property categoryName: TArray<String> read FCategoryName write FCategoryName;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TPrimaryCategoryClass;
end;
TItemClass = class
private
FAutoPay: TArray<String>;
FCondition: TArray<TConditionClass>;
FCountry: TArray<String>;
FGalleryURL: TArray<String>;
FGlobalId: TArray<String>;
FIsMultiVariationListing: TArray<String>;
FItemId: TArray<String>;
FListingInfo: TArray<TListingInfoClass>;
FLocation: TArray<String>;
FPaymentMethod: TArray<String>;
FPostalCode: TArray<String>;
FPrimaryCategory: TArray<TPrimaryCategoryClass>;
FProductId: TArray<TProductIdClass>;
FReturnsAccepted: TArray<String>;
FSellingStatus: TArray<TSellingStatusClass>;
FShippingInfo: TArray<TShippingInfoClass>;
FTitle: TArray<String>;
FTopRatedListing: TArray<String>;
FViewItemURL: TArray<String>;
public
property autoPay: TArray<String> read FAutoPay write FAutoPay;
property condition: TArray<TConditionClass> read FCondition write FCondition;
property country: TArray<String> read FCountry write FCountry;
property galleryURL: TArray<String> read FGalleryURL write FGalleryURL;
property globalId: TArray<String> read FGlobalId write FGlobalId;
property isMultiVariationListing: TArray<String> read FIsMultiVariationListing write FIsMultiVariationListing;
property itemId: TArray<String> read FItemId write FItemId;
property listingInfo: TArray<TListingInfoClass> read FListingInfo write FListingInfo;
property location: TArray<String> read FLocation write FLocation;
property paymentMethod: TArray<String> read FPaymentMethod write FPaymentMethod;
property postalCode: TArray<String> read FPostalCode write FPostalCode;
property primaryCategory: TArray<TPrimaryCategoryClass> read FPrimaryCategory write FPrimaryCategory;
property productId: TArray<TProductIdClass> read FProductId write FProductId;
property returnsAccepted: TArray<String> read FReturnsAccepted write FReturnsAccepted;
property sellingStatus: TArray<TSellingStatusClass> read FSellingStatus write FSellingStatus;
property shippingInfo: TArray<TShippingInfoClass> read FShippingInfo write FShippingInfo;
property title: TArray<String> read FTitle write FTitle;
property topRatedListing: TArray<String> read FTopRatedListing write FTopRatedListing;
property viewItemURL: TArray<String> read FViewItemURL write FViewItemURL;
destructor Destroy; override;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TItemClass;
end;
TSearchResultClass = class
private
FAcount: String;
FItem: TArray<TItemClass>;
public
property Acount: String read FAcount write FAcount;
property item: TArray<TItemClass> read FItem write FItem;
destructor Destroy; override;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TSearchResultClass;
end;
TFindCompletedItemsResponseClass = class
private
FAck: TArray<String>;
FSearchResult: TArray<TSearchResultClass>;
FTimestamp: TArray<String>;
FVersion: TArray<String>;
public
property ack: TArray<String> read FAck write FAck;
property searchResult: TArray<TSearchResultClass> read FSearchResult write FSearchResult;
property timestamp: TArray<String> read FTimestamp write FTimestamp;
property version: TArray<String> read FVersion write FVersion;
destructor Destroy; override;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TFindCompletedItemsResponseClass;
end;
TRootClass = class
private
FFindCompletedItemsResponse: TArray<TFindCompletedItemsResponseClass>;
public
property findCompletedItemsResponse: TArray<TFindCompletedItemsResponseClass> read FFindCompletedItemsResponse write FFindCompletedItemsResponse;
destructor Destroy; override;
function ToJsonString: string;
class function FromJsonString(AJsonString: string): TRootClass;
end;
implementation
{TConditionClass}
function TConditionClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TConditionClass.FromJsonString(AJsonString: string): TConditionClass;
begin
result := TJson.JsonToObject<TConditionClass>(AJsonString)
end;
{TListingInfoClass}
function TListingInfoClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TListingInfoClass.FromJsonString(AJsonString: string): TListingInfoClass;
begin
result := TJson.JsonToObject<TListingInfoClass>(AJsonString)
end;
{TConvertedCurrentPriceClass}
function TConvertedCurrentPriceClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TConvertedCurrentPriceClass.FromJsonString(AJsonString: string): TConvertedCurrentPriceClass;
begin
result := TJson.JsonToObject<TConvertedCurrentPriceClass>(AJsonString)
end;
{TCurrentPriceClass}
function TCurrentPriceClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TCurrentPriceClass.FromJsonString(AJsonString: string): TCurrentPriceClass;
begin
result := TJson.JsonToObject<TCurrentPriceClass>(AJsonString)
end;
{TSellingStatusClass}
destructor TSellingStatusClass.Destroy;
var
LcurrentPriceItem: TCurrentPriceClass;
LconvertedCurrentPriceItem: TConvertedCurrentPriceClass;
begin
for LcurrentPriceItem in FCurrentPrice do
LcurrentPriceItem.free;
for LconvertedCurrentPriceItem in FConvertedCurrentPrice do
LconvertedCurrentPriceItem.free;
inherited;
end;
function TSellingStatusClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TSellingStatusClass.FromJsonString(AJsonString: string): TSellingStatusClass;
begin
result := TJson.JsonToObject<TSellingStatusClass>(AJsonString)
end;
{TShippingInfoClass}
function TShippingInfoClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TShippingInfoClass.FromJsonString(AJsonString: string): TShippingInfoClass;
begin
result := TJson.JsonToObject<TShippingInfoClass>(AJsonString)
end;
{TProductIdClass}
function TProductIdClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TProductIdClass.FromJsonString(AJsonString: string): TProductIdClass;
begin
result := TJson.JsonToObject<TProductIdClass>(AJsonString)
end;
{TPrimaryCategoryClass}
function TPrimaryCategoryClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TPrimaryCategoryClass.FromJsonString(AJsonString: string): TPrimaryCategoryClass;
begin
result := TJson.JsonToObject<TPrimaryCategoryClass>(AJsonString)
end;
{TItemClass}
destructor TItemClass.Destroy;
var
LprimaryCategoryItem: TPrimaryCategoryClass;
LproductIdItem: TProductIdClass;
LshippingInfoItem: TShippingInfoClass;
LsellingStatusItem: TSellingStatusClass;
LlistingInfoItem: TListingInfoClass;
LconditionItem: TConditionClass;
begin
for LprimaryCategoryItem in FPrimaryCategory do
LprimaryCategoryItem.free;
for LproductIdItem in FProductId do
LproductIdItem.free;
for LshippingInfoItem in FShippingInfo do
LshippingInfoItem.free;
for LsellingStatusItem in FSellingStatus do
LsellingStatusItem.free;
for LlistingInfoItem in FListingInfo do
LlistingInfoItem.free;
for LconditionItem in FCondition do
LconditionItem.free;
inherited;
end;
function TItemClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TItemClass.FromJsonString(AJsonString: string): TItemClass;
begin
result := TJson.JsonToObject<TItemClass>(AJsonString)
end;
{TSearchResultClass}
destructor TSearchResultClass.Destroy;
var
LitemItem: TItemClass;
begin
for LitemItem in FItem do
LitemItem.free;
inherited;
end;
function TSearchResultClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TSearchResultClass.FromJsonString(AJsonString: string): TSearchResultClass;
begin
result := TJson.JsonToObject<TSearchResultClass>(AJsonString)
end;
{TFindCompletedItemsResponseClass}
destructor TFindCompletedItemsResponseClass.Destroy;
var
LsearchResultItem: TSearchResultClass;
begin
for LsearchResultItem in FSearchResult do
LsearchResultItem.free;
inherited;
end;
function TFindCompletedItemsResponseClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TFindCompletedItemsResponseClass.FromJsonString(AJsonString: string): TFindCompletedItemsResponseClass;
begin
result := TJson.JsonToObject<TFindCompletedItemsResponseClass>(AJsonString)
end;
{TRootClass}
destructor TRootClass.Destroy;
var
LfindCompletedItemsResponseItem: TFindCompletedItemsResponseClass;
begin
for LfindCompletedItemsResponseItem in FFindCompletedItemsResponse do
LfindCompletedItemsResponseItem.free;
inherited;
end;
function TRootClass.ToJsonString: string;
begin
result := TJson.ObjectToJsonString(self);
end;
class function TRootClass.FromJsonString(AJsonString: string): TRootClass;
begin
result := TJson.JsonToObject<TRootClass>(AJsonString)
end;
end.
获得它后，您可以获得与此类似的代码。
procedure TForm1.Button1Click(Sender: TObject);
var
cr:TRootClass;
rc:TFindCompletedItemsResponseClass;
sr:TSearchResultClass;
it:TItemClass;
ss:TSellingStatusClass;
cp:TCurrentPriceClass;
str:string;
begin
cr := TRootClass.FromJsonString(Memo1.Lines.Text);
rc := cr.findCompletedItemsResponse[0];
sr := rc.searchResult[0];
it := sr.item[0];
ss := it.sellingStatus[0];
cp := ss.currentPrice[0];
// current price
Str := cp.__value__; <<=======
end;
问候。
PD：请花更长的时间来提出更好的问题以获得更好的答案。