c++类封装cjson_非常简单好用的C++JSON库CJsonObject

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我是靠谱客的博主机灵皮皮虾，最近开发中收集的这篇文章主要介绍c++类封装cjson_非常简单好用的C++JSON库CJsonObject，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

1. JSON概述

JSON： JavaScript 对象表示法( JavaScript Object Notation) 。是一种轻量级的数据交换格式。它基于ECMAScript的一个子集。许多编程语言都很容易找到JSON 解析器和 JSON 库。 JSON 文本格式在语法上与创建 JavaScript 对象的代码相同。不同语言的不同json库对json标准的支持不尽相同，为了能让尽可能多的json库都能正常解析和生成json，定义JSON的规范很重要，推荐一个JSON规范《JSON风格指南》。

2. 常用C&C++ JSON库

常用且知名度较高的C&C++的JSON库有cJSON、json-c、JsonCpp等，腾讯员工开源的一个RapidJSON以高性能著称。C&C++的JSON库比较见RapidJSON作者的比较nativejson-benchmark。

3. 非常简单易用的CJsonObject

我一直使用的json库是一个较老版本的cJSON，cJSON的好处是简单易用，而且只有两个文件，直接复制到自己的代码中就可以用。cJSON也有一个非常容易让初用者头痛的地方，一不小心就造成内存泄漏了。为此，我基于cJSON封装了一个C++版的CJsonObject，该库比cJSON更简单易用，且只要不是有意不释放内存就不会发生内存泄漏。用CJsonObject的好处在于完全不用文档，看完Demo马上就会用，不明白的看一下头文件就知道，所有函数都十分通俗易懂，最为关键的一点是解析JSON和生成JSON的编码效率非常高。当然，毕竟是经过cJSON封装而来，效率会略低于cJSON，cJSON不支持的CJsonObject也不支持。个人认为，既然已经选了json，那一点点的解析性能差异就不重要了，如果追求性能可以选protobuf。CJsonObject在我最近4年做过的8个项目中广泛应用，目前有超过20人在使用，至于是否有离职同事带到其他团队去了就不太清楚。CJsonObject非常简单易用，且表现稳定，2018年5月我把它开源https://github.com/Bwar/CJsonObject，并将持续维护。

好了，来看看CJsonObject是如何简单易用：

demo.cpp：

#include #include #include "../CJsonObject.hpp"int main()

{ int iValue;

std::string strValue;

neb::CJsonObject oJson("{"refresh_interval":60,"

""dynamic_loading":["

"{"

""so_path":"plugins/User.so", "load":false, "version":1,"

""cmd":["

"{"cmd":2001, "class":"neb::CmdUserLogin"},"

"{"cmd":2003, "class":"neb::CmdUserLogout"}"

"],"

""module":["

"{"path":"im/user/login", "class":"neb::ModuleLogin"},"

"{"path":"im/user/logout", "class":"neb::ModuleLogout"}"

"]"

"},"

"{"

""so_path":"plugins/ChatMsg.so", "load":false, "version":1,"

""cmd":["

"{"cmd":2001, "class":"neb::CmdChat"}"

"],"

""module":[]"

"}"

"]"

"}");

std::cout <

oJson["dynamic_loading"][0]["cmd"][0].Get("cmd", iValue);

std::cout <

oJson["dynamic_loading"][0]["module"][0].Get("path", strValue);

std::cout <

oJson.AddEmptySubObject("depend");

oJson["depend"].Add("nebula", "https://github.com/Bwar/Nebula");

oJson["depend"].AddEmptySubArray("bootstrap");

oJson["depend"]["bootstrap"].Add("BEACON");

oJson["depend"]["bootstrap"].Add("LOGIC");

oJson["depend"]["bootstrap"].Add("LOGGER");

oJson["depend"]["bootstrap"].Add("INTERFACE");

oJson["depend"]["bootstrap"].Add("ACCESS");

std::cout <

}

Demo执行结果：[bwar@nebula demo]$ ./CJsonObjectTest{"refresh_interval":60,"dynamic_loading":[{"so_path":"plugins/User.so","load":false,"version":1,"cmd":[{"cmd":2001,"class":"neb::CmdUserLogin"},{"cmd":2003,"class":"neb::CmdUserLogout"}],"module":[{"path":"im/user/login","class":"neb::ModuleLogin"},{"path":"im/user/logout","class":"neb::ModuleLogout"}]},{"so_path":"plugins/ChatMsg.so","load":false,"version":1,"cmd":[{"cmd":2001,"class":"neb::CmdChat"}],"module":[]}]}-------------------------------------------------------------------neb::CmdUserLogoutiValue = 2001strValue = im/user/login-------------------------------------------------------------------{"refresh_interval":60,"dynamic_loading":[{"so_path":"plugins/User.so","load":false,"version":1,"cmd":[{"cmd":2001,"class":"neb::CmdUserLogin"},{"cmd":2003,"class":"neb::CmdUserLogout"}],"module":[{"path":"im/user/login","class":"neb::ModuleLogin"},{"path":"im/user/logout","class":"neb::ModuleLogout"}]},{"so_path":"plugins/ChatMsg.so","load":false,"version":1,"cmd":[{"cmd":2001,"class":"neb::CmdChat"}],"module":[]}],"depend":{"nebula":"https://github.com/Bwar/Nebula","bootstrap":["BEACON","LOGIC","LOGGER","INTERFACE","ACCESS"]}}-------------------------------------------------------------------{"refresh_interval": 60,"dynamic_loading": [{"so_path":"plugins/User.so","load":false,"version": 1,"cmd": [{"cmd": 2001,"class":"neb::CmdUserLogin"}, {"cmd": 2003,"class":"neb::CmdUserLogout"}],"module": [{"path":"im/user/login","class":"neb::ModuleLogin"}, {"path":"im/user/logout","class":"neb::ModuleLogout"}]}, {"so_path":"plugins/ChatMsg.so","load":false,"version": 1,"cmd": [{"cmd": 2001,"class":"neb::CmdChat"}],"module": []}],"depend": {"nebula":"https://github.com/Bwar/Nebula","bootstrap": ["BEACON","LOGIC","LOGGER","INTERFACE","ACCESS"]}}

再来看看头文件，一看就知道如何使用：

/*******************************************************************************

* Project: neb

* @file CJsonObject.hpp

* @brief Json

* @author bwarliao

* @date: 2014-7-16

* @note

* Modify history:

******************************************************************************/#ifndef CJSONOBJECT_HPP_#define CJSONOBJECT_HPP_#include #include #include #include #include #include #include #include #include #include #include "cJSON.h"namespace neb

{class CJsonObject

{public: // method of ordinary json object or json array CJsonObject();

CJsonObject(const std::string& strJson);

CJsonObject(const CJsonObject* pJsonObject);

CJsonObject(const CJsonObject& oJsonObject); virtual ~CJsonObject();

CJsonObject& operator=(const CJsonObject& oJsonObject); bool operator==(const CJsonObject& oJsonObject) const; bool Parse(const std::string& strJson); void Clear(); bool IsEmpty() const; bool IsArray() const;

std::string ToString() const;

std::string ToFormattedString() const; const std::string& GetErrMsg() const

{ return(m_strErrMsg);

}public: // method of ordinary json object

bool AddEmptySubObject(const std::string& strKey); bool AddEmptySubArray(const std::string& strKey);

CJsonObject& operator[](const std::string& strKey);

std::string operator()(const std::string& strKey) const; bool Get(const std::string& strKey, CJsonObject& oJsonObject) const; bool Get(const std::string& strKey, std::string& strValue) const; bool Get(const std::string& strKey, int32& iValue) const; bool Get(const std::string& strKey, uint32& uiValue) const; bool Get(const std::string& strKey, int64& llValue) const; bool Get(const std::string& strKey, uint64& ullValue) const; bool Get(const std::string& strKey, bool& bValue) const; bool Get(const std::string& strKey, float& fValue) const; bool Get(const std::string& strKey, double& dValue) const; bool Add(const std::string& strKey, const CJsonObject& oJsonObject); bool Add(const std::string& strKey, const std::string& strValue); bool Add(const std::string& strKey, int32 iValue); bool Add(const std::string& strKey, uint32 uiValue); bool Add(const std::string& strKey, int64 llValue); bool Add(const std::string& strKey, uint64 ullValue); bool Add(const std::string& strKey, bool bValue, bool bValueAgain); bool Add(const std::string& strKey, float fValue); bool Add(const std::string& strKey, double dValue); bool Delete(const std::string& strKey); bool Replace(const std::string& strKey, const CJsonObject& oJsonObject); bool Replace(const std::string& strKey, const std::string& strValue); bool Replace(const std::string& strKey, int32 iValue); bool Replace(const std::string& strKey, uint32 uiValue); bool Replace(const std::string& strKey, int64 llValue); bool Replace(const std::string& strKey, uint64 ullValue); bool Replace(const std::string& strKey, bool bValue, bool bValueAgain); bool Replace(const std::string& strKey, float fValue); bool Replace(const std::string& strKey, double dValue);public: // method of json array

int GetArraySize();

CJsonObject& operator[](unsigned int uiWhich);

std::string operator()(unsigned int uiWhich) const; bool Get(int iWhich, CJsonObject& oJsonObject) const; bool Get(int iWhich, std::string& strValue) const; bool Get(int iWhich, int32& iValue) const; bool Get(int iWhich, uint32& uiValue) const; bool Get(int iWhich, int64& llValue) const; bool Get(int iWhich, uint64& ullValue) const; bool Get(int iWhich, bool& bValue) const; bool Get(int iWhich, float& fValue) const; bool Get(int iWhich, double& dValue) const; bool Add(const CJsonObject& oJsonObject); bool Add(const std::string& strValue); bool Add(int32 iValue); bool Add(uint32 uiValue); bool Add(int64 llValue); bool Add(uint64 ullValue); bool Add(int iAnywhere, bool bValue); bool Add(float fValue); bool Add(double dValue); bool AddAsFirst(const CJsonObject& oJsonObject); bool AddAsFirst(const std::string& strValue); bool AddAsFirst(int32 iValue); bool AddAsFirst(uint32 uiValue); bool AddAsFirst(int64 llValue); bool AddAsFirst(uint64 ullValue); bool AddAsFirst(int iAnywhere, bool bValue); bool AddAsFirst(float fValue); bool AddAsFirst(double dValue); bool Delete(int iWhich); bool Replace(int iWhich, const CJsonObject& oJsonObject); bool Replace(int iWhich, const std::string& strValue); bool Replace(int iWhich, int32 iValue); bool Replace(int iWhich, uint32 uiValue); bool Replace(int iWhich, int64 llValue); bool Replace(int iWhich, uint64 ullValue); bool Replace(int iWhich, bool bValue, bool bValueAgain); bool Replace(int iWhich, float fValue); bool Replace(int iWhich, double dValue);private:

CJsonObject(cJSON* pJsonData);private:

cJSON* m_pJsonData;

cJSON* m_pExternJsonDataRef;

std::string m_strErrMsg;

std::map m_mapJsonArrayRef;

std::map<:string> m_mapJsonObjectRef;

};

}#endif /* CJSONHELPER_HPP_ */