Use C ++ jsoncpp (including source code download)

Preface

JSON is a lightweight data definition format. It is easier to learn and use than XML, and its extended functions are no worse than XML. Using JSON for data exchange is a good choice.
JSON is called JavaScript Object Notation. As the name suggests, JSON is used to mark JavaScript objects. For details, see http://www.json.org /.
This article chooses a third-party library jsoncpp to parse JSON. jsoncpp is a well-known C ++ Parsing Library, which is also the first on the JSON official website.

Introduction to jsoncpp

Jsoncpp mainly contains three types of Class: Value reader writer.
All objects and class names in jsoncpp are in namespace JSON, including JSON. h.
Note: JSON: value can only process ANSI strings.ProgramIt is recommended to add an adapt class to adapt to unicode encoding.

Download and compile

The running environment is: RedHat 5.5 + G ++ version 4.6.1 + GNU make 3.81 + jsoncpp-0.5.0

Yes: http://sourceforge.net/projects/jsoncpp/

Decompress the package to get the jsoncpp-src-0.5.0 folder, we only need the header file and CPP file of jsoncpp, where the header file of jsonscpp is located in jsoncpp-src-0.5.0 \ include \ JSON, And the CPP file of jsoncpp is located in jsoncpp-src-0.5.0 \ SRC \ lib_json.

Here I will list our working directories:

Jsoncpp/ //  Working directory  
 | -- Include //  Header file root directory  
 | -- JSON //  JSON header file, corresponding to jsoncpp-src-0.5.0 \ include \ JSON  
 | -- SRC //  CPP source code file root directory  
 | -- JSON // Jsoncpp source code file, corresponding to jsoncpp-src-0.5.0 \ SRC \ lib_json  
 | -- Main. cpp //  Example of calling jsoncpp for our main functionCode  
 
| -- Makefile //  Makefile. You don't need to talk about it. If you don't understand it, please refer to my blog's makefile best practices. 

 

Deserialization of JSON objects

Suppose there is a JSON object as follows:

{
 "  Name  " : " JSON ″,  
      "  Array  " :[
{
 "  CPP  " : "  Jsoncpp  " 
},
{
 "  Java  " :"  Jsoninjava  " 
},
{
 "  PHP  " : "  Support  " 
}
]
}

The anti-serial number code for JSON is as follows:

 Void Readjson (){
 Using   Namespace STD;
STD :: String Strvalue = "  {\ "Name \": \ "JSON \", \ "array \": [{\ "CPP \": \ "jsoncpp \"}, {\ "Java \": \ "jsoninjava \" },{ \ "php \": \ "support \"}]}  " ;

JSON: reader;
JSON: Value value;

 If (Reader. parse (strvalue, value ))
{
STD :: String   Out = Value [ " Name  " ]. Asstring ();
STD: cout < Out <STD: Endl;
 Const JSON: Value arrayobj = value [ "  Array  " ];
 For (Unsigned Int I = 0 ; I <arrayobj. Size (); I ++)
{
 If (! Arrayobj [I]. ismember ( "  CPP  " ))
 Continue ;
 Out = Arrayobj [I] [ "  CPP  " ]. Asstring ();
STD: cout < Out ;
 If (I! = (Arrayobj. Size ()- 1 ))
STD: cout <STD: Endl;
}
}
}

 

Serialize a json object

 Void Writejson (){
 Using   Namespace STD;

JSON: Value root;
JSON: Value arrayobj;
JSON: value item;

Item [ "  CPP  " ] = "  Jsoncpp " ;
Item [ "  Java  " ] = "  Jsoninjava  " ;
Item [ "  PHP  " ] = "  Support  " ;
Arrayobj. append (item );

Root ["  Name  " ] = "  JSON  " ;
Root [ "  Array  " ] = Arrayobj;

Root. tostyledstring ();
STD :: String   Out = Root. tostyledstring ();
STD: cout < Out <STD: Endl;
}

 

Download complete code

Click here to download

After the download, run the following command:

 
Unzip jsoncpp.zip
CD jsoncpp
Make
./Main