c++11 json解析库nlohmann/json.hpp文件整个代码由一个头文件组成 json.hpp，没有子项目，没有依赖关系，没有复杂的构建系统，使用起来非常方便。
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读写主要有两种方式，第一种根据键值对读写，第二种直接遍历json文件读写。
1、根据键值对读写
假设有个json文件，格式如下：
{
"test": [
{
"FixedParameters": {
"bit_depth": 10,
"dark_level": 5.5,
"dark_time": 100,
"dynamic_range": 0.1
},
"InitialParameters":{
"InitialTime":20,
"rate":50
},
"JudgmentMechanism":{
"max_time": 100000,
"min_time": 0,
"rangeMax": 0.9,
"rangeMin": 0.3,
"targetMax": 0.9,
"targetMin": 0.5
},
"IterationStepLength":{
"belowNormalRange":1.5,
"aboveNormalRange":2,
"totalIterations":10
},
"IsUseROIs":{
"isUseROIs":false,
"isCalculateEntireROIGray":false,
"pixelTotalNumber":1000,
"isUseWeightedAverage":false,
"ROIS":[
{
"Name":"ROI1",
"weight":1,
"x":0,
"y":0,
"width":100,
"height":100
}
]
},
"Index": 1,
"Name": "data1",
"SerialNumber": "0000000000"
},
{
"FixedParameters": {
"bit_depth": 200,
"dark_level": 10.0,
"dark_time": 3000,
"dynamic_range": 0.5
},
"InitialParameters":{
"InitialTime":0,
"rate":20
},
"JudgmentMechanism":{
"max_time": 200000,
"min_time": 11111,
"rangeMax": 0.9,
"rangeMin": 0.3,
"targetMax": 0.9,
"targetMin": 0.5
},
"IterationStepLength":{
"belowNormalRange":1.5,
"aboveNormalRange":2,
"totalIterations":10
},
"IsUseROIs":{
"isUseROIs":false,
"isCalculateEntireROIGray":false,
"pixelTotalNumber":1000,
"isUseWeightedAverage":false,
"ROIS":[
{
"Name":"ROI1",
"weight":1,
"x":0,
"y":0,
"width":100,
"height":200
}
]
},
"Index": 2,
"Name": "data2",
"SerialNumber": "1111111111"
}
]
}
读json文件：
头文件的部分内容
#pragma once
#include <iostream>
#include <fstream>
#include <string>
#include <mutex>
#include "json.hpp"
using namespace std;
using json = nlohmann::ordered_json;
struct FixedParameters_
{
int bit_depth;
double dark_level;
double dark_time;
double dynamic_range;
};
struct InitialParameters_
{
int InitialTime;
bool isAutoUpdateInitTime;
bool isAutoUpdateMaxMinTime;
int rate;
};
struct JudgmentMechanism_
{
int max_time;
int min_time;
double rangeMax;
double rangeMin;
double target_max;
double target_min;
};
struct IterationStepLength_
{
double belowNormalRange;
double aboveNormalRange;
int totalIterations;
};
struct ROIS
{
double weight;
int x;
int y;
int width;
int height;
};
struct IsUseROIs_
{
bool isUseROIs;
bool isCalculateEntireROIGray;
int pixelTotalNumber;
bool isUseWeightedAverage;
std::map<std::string, ROIS> rois;
};
struct Param
{
FixedParameters_ fixedParameters;
InitialParameters_ initialParameters;
JudgmentMechanism_ judgmentMechanism;
IterationStepLength_ iterationStepLength;
IsUseROIs_ isUseROIs;
std::string SN;
};
struct AEConfig
{
std::map<std::string, Param> AE_Config;
};
class ReadWriteConfig
{
public:
static ReadWriteConfig *getinstance();
ReadWriteConfig();
//read/write json
AEConfig ReadAEConfig(string configPath);
void WriteAEConfig(AEConfig AE_Config, string configPath);
private:
static ReadWriteConfig *m_ReadWriteConfig;
string path;
json m_JsonConfig;
};
CPP部分
AEConfig ReadWriteConfig::ReadAEConfig(string configPath)
{
m_mutex.lock();
if (configPath != "")
path = configPath;
std::ifstream ifs(path, std::fstream::in);
if (ifs.fail())
{
//return 0;
m_mutex.unlock();
throw std::runtime_error("Unable to open AEConfig File.");
}
ifs >> m_JsonConfig;
ifs.close();
AEConfig AE_Config;
auto AEConfig = m_JsonConfig["test"];
for (auto& it : AEConfig.items())
{
string cameraName = it.value()["Name"].get<string>();
AE_Config.AE_Config[cameraName].SN = it.value()["SerialNumber"].get<string>();
AE_Config.AE_Config[cameraName].fixedParameters.bit_depth = it.value()["FixedParameters"]["bit_depth"].get<int>();
AE_Config.AE_Config[cameraName].fixedParameters.dark_level = it.value()["FixedParameters"]["dark_level"].get<double>();
AE_Config.AE_Config[cameraName].fixedParameters.dark_time = it.value()["FixedParameters"]["dark_time"].get<double>();
AE_Config.AE_Config[cameraName].fixedParameters.dynamic_range = it.value()["FixedParameters"]["dynamic_range"].get<double>();
AE_Config.AE_Config[cameraName].initialParameters.InitialTime = it.value()["InitialParameters"]["InitialTime"].get<int>();
AE_Config.AE_Config[cameraName].initialParameters.isAutoUpdateInitTime = it.value()["InitialParameters"]["isAutoUpdateInitTime"].get<bool>();
AE_Config.AE_Config[cameraName].initialParameters.isAutoUpdateMaxMinTime = it.value()["InitialParameters"]["isAutoUpdateMaxMinTime"].get<bool>();
AE_Config.AE_Config[cameraName].initialParameters.rate = it.value()["InitialParameters"]["rate"].get<int>();
AE_Config.AE_Config[cameraName].judgmentMechanism.max_time = it.value()["JudgmentMechanism"]["max_time"].get<int>();
AE_Config.AE_Config[cameraName].judgmentMechanism.min_time = it.value()["JudgmentMechanism"]["min_time"].get<int>();
AE_Config.AE_Config[cameraName].judgmentMechanism.rangeMax = it.value()["JudgmentMechanism"]["rangeMax"].get<double>();
AE_Config.AE_Config[cameraName].judgmentMechanism.rangeMin = it.value()["JudgmentMechanism"]["rangeMin"].get<double>();
AE_Config.AE_Config[cameraName].judgmentMechanism.target_max = it.value()["JudgmentMechanism"]["targetMax"].get<double>();
AE_Config.AE_Config[cameraName].judgmentMechanism.target_min = it.value()["JudgmentMechanism"]["targetMin"].get<double>();
AE_Config.AE_Config[cameraName].iterationStepLength.belowNormalRange = it.value()["IterationStepLength"]["belowNormalRange"].get<double>();
AE_Config.AE_Config[cameraName].iterationStepLength.aboveNormalRange = it.value()["IterationStepLength"]["aboveNormalRange"].get<double>();
AE_Config.AE_Config[cameraName].iterationStepLength.totalIterations = it.value()["IterationStepLength"]["totalIterations"].get<int>();
AE_Config.AE_Config[cameraName].isUseROIs.isUseROIs = it.value()["IsUseROIs"]["isUseROIs"].get<bool>();
AE_Config.AE_Config[cameraName].isUseROIs.isCalculateEntireROIGray = it.value()["IsUseROIs"]["isCalculateEntireROIGray"].get<bool>();
AE_Config.AE_Config[cameraName].isUseROIs.pixelTotalNumber = it.value()["IsUseROIs"]["pixelTotalNumber"].get<int>();
AE_Config.AE_Config[cameraName].isUseROIs.isUseWeightedAverage = it.value()["IsUseROIs"]["isUseWeightedAverage"].get<bool>();
auto roiConfig = it.value()["IsUseROIs"]["ROIS"];
for (auto& it : roiConfig.items())
{
string roiName = it.value()["Name"].get<string>();
ROIS rois;
rois.weight = it.value()["weight"].get<double>();
rois.x = it.value()["x"].get<int>();
rois.y = it.value()["y"].get<int>();
rois.width = it.value()["width"].get<int>();
rois.height = it.value()["height"].get<int>();
AE_Config.AE_Config[cameraName].isUseROIs.rois[roiName] = rois;
}
}
m_mutex.unlock();
return AE_Config;
}
写json文件
void ReadWriteConfig::WriteAEConfig(AEConfig AE_Config, string configPath)
{
m_mutex.lock();
if (configPath != "")
path = configPath;
m_JsonConfig["test"].clear();
for (auto gt = AE_Config.AE_Config.begin(); gt != AE_Config.AE_Config.end(); gt++)
{
json AutoExposure;
AutoExposure["Name"] = gt->first;
AutoExposure["SerialNumber"] = gt->second.SN;
AutoExposure["FixedParameters"]["bit_depth"] = gt->second.fixedParameters.bit_depth;
AutoExposure["FixedParameters"]["dark_level"] = gt->second.fixedParameters.dark_level;
AutoExposure["FixedParameters"]["dark_time"] = gt->second.fixedParameters.dark_time;
AutoExposure["FixedParameters"]["dynamic_range"] = gt->second.fixedParameters.dynamic_range;
AutoExposure["InitialParameters"]["InitialTime"] = gt->second.initialParameters.InitialTime;
AutoExposure["InitialParameters"]["isAutoUpdateInitTime"] = gt->second.initialParameters.isAutoUpdateInitTime;
AutoExposure["InitialParameters"]["isAutoUpdateMaxMinTime"] = gt->second.initialParameters.isAutoUpdateMaxMinTime;
AutoExposure["InitialParameters"]["rate"] = gt->second.initialParameters.rate;
AutoExposure["JudgmentMechanism"]["max_time"] = gt->second.judgmentMechanism.max_time;
AutoExposure["JudgmentMechanism"]["min_time"] = gt->second.judgmentMechanism.min_time;
AutoExposure["JudgmentMechanism"]["rangeMax"] = gt->second.judgmentMechanism.rangeMax;
AutoExposure["JudgmentMechanism"]["rangeMin"] = gt->second.judgmentMechanism.rangeMin;
AutoExposure["JudgmentMechanism"]["targetMax"] = gt->second.judgmentMechanism.target_max;
AutoExposure["JudgmentMechanism"]["targetMin"] = gt->second.judgmentMechanism.target_min;
AutoExposure["IterationStepLength"]["belowNormalRange"] = gt->second.iterationStepLength.belowNormalRange;
AutoExposure["IterationStepLength"]["aboveNormalRange"] = gt->second.iterationStepLength.aboveNormalRange;
AutoExposure["IterationStepLength"]["totalIterations"] = gt->second.iterationStepLength.totalIterations;
AutoExposure["IsUseROIs"]["isUseROIs"] = gt->second.isUseROIs.isUseROIs;
AutoExposure["IsUseROIs"]["isCalculateEntireROIGray"] = gt->second.isUseROIs.isCalculateEntireROIGray;
AutoExposure["IsUseROIs"]["pixelTotalNumber"] = gt->second.isUseROIs.pixelTotalNumber;
AutoExposure["IsUseROIs"]["isUseWeightedAverage"] = gt->second.isUseROIs.isUseWeightedAverage;
for (auto it = gt->second.isUseROIs.rois.begin(); it != gt->second.isUseROIs.rois.end(); it++)
{
json roi;
roi["Name"] = it->first;
roi["weight"] = it->second.weight;
roi["x"] = it->second.x;
roi["y"] = it->second.y;
roi["width"] = it->second.width;
roi["height"] = it->second.height;
AutoExposure["IsUseROIs"]["ROIS"].push_back(roi);
}
m_JsonConfig["test"].push_back(AutoExposure);
}
std::ofstream os(path);
if (os.fail())
{
//return 0;
m_mutex.unlock();
throw std::runtime_error("Unable to open AEConfig File.");
}
os << m_JsonConfig.dump(4);
os.close();
m_mutex.unlock();
}
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