Use C ++ to test the JSON third-party library JsonCpp

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. If the C ++ program uses Unicode encoding, it is best to add an Adapt class for adaptation.

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 and 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 the jsoncpp-src-0.5.0includejson and the cpp file of jsoncpp is located in the jsoncpp-src-0.5.0srclib_json.

Here I will list our working directories:

Jsoncpp // working directory

| -- Include // the root directory of the header file

| -- Json // json header file, which corresponds to the jsoncpp-src-0.5.0includejson

| -- Src // cpp source code file root directory

| -- Json // jsoncpp source code file, corresponding to the jsoncpp-src-0.5.0srclib_json

| -- Main. cpp // Our main function calls the sample code of jsoncpp.

| -- Makefile // makefile

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:

 
 

  
  
voidreadJson() {  
  
  
usingnamespacestd;  
  
  
std::stringstrValue = "{\"name\":\"json\",\"array\":[{\"cpp\":\"jsoncpp\"},{\"java\":\"jsoninjava\"},{\"php\":\"support\"}]}";  
  
  
Json::Reader reader;  
  
  
Json::Value value;  
  
  
if(reader.parse(strValue, value))  
  
  
{  
  
  
std::stringout= value["name"].asString();  
  
  
std::cout <<out<<std::endl;  
  
  
constJson::Value arrayObj = value["array"];  
  
  
　for(unsigned inti = 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

 
 

  
  
voidwriteJson() {  
  
  
usingnamespacestd;  
  
  
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::stringout= 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

Original article: http://www.cnblogs.com/ggjucheng/archive/2012/01/03/2311107.html