JsonCpp如何判断是否有某个KEY



JsonCpp如何判断是否有某个KEY，使用json[“key”]和isXXX的函数即可。
如果json中没有key键，则会创建一个空成员或者返回一个空成员。

// Access an object value by name, create a null member if it does not exist.Value &operator[]( const char *key );// Access an object value by name, returns null if there is no member with that name.const Value &operator[]( const char *key ) const;// Access an object value by name, create a null member if it does not exist.Value &operator[]( const std::string &key );// Access an object value by name, returns null if there is no member with that name.const Value &operator[]( const std::string &key ) const;bool isNull() const;bool isBool() const;bool isInt() const;bool isUInt() const;bool isIntegral() const;bool isDouble() const;bool isNumeric() const;bool isString() const;bool isArray() const;bool isObject() const;
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

例如要判断Json数据中是否有{“status”:”1”}数据，则可以

if(json["staus"].isString()){    string temp = json["staus"].asCString();}
1
2
3

如果Json中没有status键就不会提取该数据。