QJsonDocument Class

  {
      "Array": [
          true,
          999,
          "string"
      ],
      "Key": "Value",
      "null": null
  }

  {"Array":[true,999,"string"],"Key":"Value","null":null}

成员函数

QJsonDocument::QJsonDocument()

Constructs an empty and invalid document.

QJsonDocument::QJsonDocument(const QJsonObject &object)

Creates a QJsonDocument from object.

QJsonDocument::QJsonDocument(const QJsonArray &array)

Constructs a QJsonDocument from array.

QJsonDocument::QJsonDocument(const QJsonDocument &other)

Creates a copy of the other document.

QJsonDocument::~QJsonDocument()

Deletes the document.

Binary data set with fromRawData is not freed.

QJsonArray QJsonDocument::array() const

Returns the QJsonArray contained in the document.

Returns an empty array if the document contains an object.

参见 isArray(), object(), and setArray().

[static] QJsonDocument QJsonDocument::fromBinaryData(const QByteArray &data, DataValidation validation = Validate)

Creates a QJsonDocument from data.

validation decides whether the data is checked for validity before being used. By default the data is validated. If the data is not valid, the method returns a null document.

参见 toBinaryData(), fromRawData(), isNull(), and DataValidation.

[static] QJsonDocument QJsonDocument::fromJson(const QByteArray &json, QJsonParseError *error = Q_NULLPTR)

Parses json as a UTF-8 encoded JSON document, and creates a QJsonDocument from it.

Returns a valid (non-null) QJsonDocument if the parsing succeeds. If it fails, the returned document will be null, and the optional error variable will contain further details about the error.

参见 toJson(), QJsonParseError, and isNull().

[static] QJsonDocument QJsonDocument::fromRawData(const char *data, int size, DataValidation validation = Validate)

Creates a QJsonDocument that uses the first size bytes from data. It assumes data contains a binary encoded JSON document. The created document does not take ownership of data and the caller has to guarantee that data will not be deleted or modified as long as any QJsonDocument, QJsonObject or QJsonArray still references the data.

data has to be aligned to a 4 byte boundary.

validation decides whether the data is checked for validity before being used. By default the data is validated. If the data is not valid, the method returns a null document.

Returns a QJsonDocument representing the data.

参见 rawData(), fromBinaryData(), isNull(), and DataValidation.

[static] QJsonDocument QJsonDocument::fromVariant(const QVariant &variant)

Creates a QJsonDocument from the QVariant variant.

If the variant contains any other type than a QVariantMap, QVariantHash, QVariantList or QStringList, the returned document is invalid.

参见 toVariant().

bool QJsonDocument::isArray() const

Returns true if the document contains an array.

参见 array() and isObject().

bool QJsonDocument::isEmpty() const

Returns true if the document doesn't contain any data.

bool QJsonDocument::isNull() const

returns true if this document is null.

Null documents are documents created through the default constructor.

Documents created from UTF-8 encoded text or the binary format are validated during parsing. If validation fails, the returned document will also be null.

bool QJsonDocument::isObject() const

Returns true if the document contains an object.

参见 object() and isArray().

QJsonObject QJsonDocument::object() const

Returns the QJsonObject contained in the document.

Returns an empty object if the document contains an array.

参见 isObject(), array(), and setObject().

const char *QJsonDocument::rawData(int *size) const

Returns the raw binary representation of the data size will contain the size of the returned data.

This method is useful to e.g. stream the JSON document in it's binary form to a file.

void QJsonDocument::setArray(const QJsonArray &array)

Sets array as the main object of this document.

参见 setObject() and array().

void QJsonDocument::setObject(const QJsonObject &object)

Sets object as the main object of this document.

参见 setArray() and object().

QByteArray QJsonDocument::toBinaryData() const

Returns a binary representation of the document.

The binary representation is also the native format used internally in Qt, and is very efficient and fast to convert to and from.

The binary format can be stored on disk and interchanged with other applications or computers. fromBinaryData() can be used to convert it back into a JSON document.

参见 fromBinaryData().

QByteArray QJsonDocument::toJson(JsonFormat format = Indented) const

Converts the QJsonDocument to a UTF-8 encoded JSON document in the provided format.

参见 fromJson() and JsonFormat.

QVariant QJsonDocument::toVariant() const

Returns a QVariant representing the Json document.

The returned variant will be a QVariantList if the document is a QJsonArray and a QVariantMap if the document is a QJsonObject.

参见 fromVariant() and QJsonValue::toVariant().

bool QJsonDocument::operator!=(const QJsonDocument &other) const

returns true if other is not equal to this document

QJsonDocument &QJsonDocument::operator=(const QJsonDocument &other)

Assigns the other document to this QJsonDocument. Returns a reference to this object.

bool QJsonDocument::operator==(const QJsonDocument &other) const

Returns true if the other document is equal to this document.