如何在Delphi中解析JSON？

Question

我有一个像这样的 JSON：

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{\n"Content": [{\n    "Identifier": "AABBCC",\n    "Description": "test terfdfg",\n    "GenericProductIdentifier": "AABBCC",\n    "ProductFamilyDescription": "sampling",\n    "LifeCycleStatus": "ACTIVE",\n    "Price": {\n        "Value": 1.00,\n        "Quantity": 1000\n    },\n    "LeadTimeWeeks": "16",\n    "FullBoxQty": 200,\n}],\n"TotalElements": 1,\n"TotalPages": 1,\n"NumberOfElements": 1,\n"First": true,\n"Size": 1,\n"Number": 0\n}\n

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在 Delphi 10.4 中，我尝试解析它，但无法访问 \'Price\' 中包含的值 \xe2\x80\x8b\xe2\x80\x8b。

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我写了这样的代码：

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var\n  vContent: TJSONArray;\n  vJson: TJSONObject;\n  vContentRow: TJSONObject;\n  i,j : Integer;\nbegin\n  Memo2.Lines.Clear;\n\n  if Memo1.Text = \'\' then\n    exit;\n\n  vJson := TJSONObject(TJSONObject.ParseJSONValue(TEncoding.ASCII.GetBytes(Memo1.Text),0));\n  try\n    vContent := TJSONArray(vJson.Get(\'Content\').JsonValue);\n\n    for i := 0 to Pred(vContent.Count) do\n    begin\n      vContentRow := TJSONObject(vContent.Items[i]);\n      for j := 0 to Pred(vContentRow.Count) do\n      begin\n        Memo2.Lines.Add(\'  \'+ vContentRow.Get(j).JsonString.Value+\' : \'+ vContentRow.Get(j).JsonValue.Value);\n      end;\n    end;\n\n    Memo2.Lines.Add(vContent.Value);\n  finally\n\n  end;\nend;\n

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读取“Price”中包含的值 \xe2\x80\x8b\xe2\x80\x8b 的正确方法是什么？

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Answer 1

以下是解析 JSON 的示例代码：

uses
  System.IOUtils, System.JSON, System.Generics.Collections;

procedure TForm1.Button1Click(Sender: TObject);

  procedure GetPrices(const S: string);
  var
    V: TJsonValue;
    O, E, P: TJsonObject;
    A: TJsonArray;
  begin
    V := TJSONObject.ParseJSONValue(S);
    if not Assigned(V) then
      raise Exception.Create('Invalid JSON');
    try
      O := V as TJSONObject;
      A := O.GetValue<TJsonArray>('Content');
      for var I := 0 to A.Count - 1 do
      begin
        E := A.Items[I] as TJsonObject; // Element
        P := E.GetValue<TJsonObject>('Price');
        ShowMessage('Value: ' + P.GetValue<string>('Value') + '  ' + 'Quantity: ' +  P.GetValue<string>('Quantity'));
      end;
    finally
      V.Free;
    end;
  end;

var
  S: string;
begin
  S := TFile.ReadAllText('d:\json.txt'); // Retrieve it using some webservice
  GetPrices(S);
end;

请注意，您的 JSON 无效，正确的定义是：

{
    "Content": [{
        "Identifier": "AABBCC",
        "Description": "test terfdfg",
        "GenericProductIdentifier": "AABBCC",
        "ProductFamilyDescription": "sampling",
        "LifeCycleStatus": "ACTIVE",
        "Price": {
            "Value": 1.00,
            "Quantity": 1000
        },
        "LeadTimeWeeks": "16",
        "FullBoxQty": 200
    }],
    "TotalElements": 1,
    "TotalPages": 1,
    "NumberOfElements": 1,
    "First": true,
    "Size": 1,
    "Number": 0
}