UE Json读写

1：添加JSON Modules

在Project.Build.cs文件中的PrivateDependencyModuleNames添加Json和JsonUtilities模块。

读取Json文件到字符串

private：
	bool LoadStringFromFile(const FString& FileName, const FString& RelaPath, FString& ResultString);

bool SlAiJsonHandle::LoadStringFromFile(const FString& FileName, const FString& RelaPath, FString& ResultString)
{
	if (!FileName.IsEmpty()) {
		//获取绝对路径 (GameContent+相对路径+文件名)
		FString AbsoPath = FPaths::GameContentDir() + RelaPath + FileName;
		//判断文件是否存在文件
		if (FPaths::FileExists(AbsoPath)) 
		{
			if (FFileHelper::LoadFileToString(ResultString, *AbsoPath))
			{
				return true;
			}
			else {
				//加载不成功
				SlAiHelper::Debug(FString("Load Error") + AbsoPath);
			}
		}
		else {
			//输出文件不存在
			SlAiHelper::Debug(FString("File Not Exist") + AbsoPath);
		}
	}
	return false;
}

解析存档方法 (读取到的json文件按内容，传入方法)

void RecordDataJsonRead(FString& Culture, float& MusicVolume, float& SoundVolume, TArray<FString>& RecordDataList);


void SlAiJsonHandle::RecordDataJsonRead(FString& Culture, float& MusicVolume, float& SoundVolume, TArray<FString>& RecordDataList)
{
	//用于保存file读取的内容
	FString JsonValue;
	//载入
	LoadStringFromFile(RecordDataFileName, RelativePath, JsonValue);
	
	//保存解析出来的数据
	TArray<TSharedPtr<FJsonValue>> JsonParsed;  
	//将JsonValue字符串中读取到JsonReader
	TSharedRef<TJsonReader<TCHAR>> JsonReader = TJsonReaderFactory<TCHAR>::Create(JsonValue);
	
	//解析。。
	//将解析的内容保存到数组
	if (FJsonSerializer::Deserialize(JsonReader, JsonParsed))   
	{
		//获取数据
		Culture = JsonParsed[0]->AsObject()->GetStringField(FString("Culture"));
		MusicVolume = JsonParsed[1]->AsObject()->GetNumberField(FString("MusicVolume"));
		SoundVolume = JsonParsed[2]->AsObject()->GetNumberField(FString("SoundVolume"));
		//获取存档数据
		TArray<TSharedPtr<FJsonValue>> RecordDataArray = JsonParsed[3]->AsObject()->GetArrayField(FString("RecordData"));
		for (int i = 0; i < RecordDataArray.Num(); ++i) 
		{
			FString RecordDataName = RecordDataArray[i]->AsObject()->GetStringField(FString::FromInt(i));
			RecordDataList.Add(RecordDataName);
		}
	}
	else 
	{
		SlAiHelper::Debug(FString("Deserialize Failed"));
	}

}

初始化存档数据

private:
	//初始化存档数据
	void InitRecordData();

void SlAiDataHandle::InitRecordData()
{
	//RecordName = FString("");
	//获取语言
	FString Culture;
	//读取存档数据
	SlAiSingleton<SlAiJsonHandle>::Get()->RecordDataJsonRead(Culture, MusicVolume, SoundVolume, RecordDataList);	
	//初始化语言
	ChangeLocalizationCulture(GetEnumValueFromString<ECultureTeam>(FString("ECultureTeam"), Culture));
}

把数据写入Json文件

保存字符串到文件

private：

	bool WriteFileWithJsonData(const FString& JsonStr, const FString& RelaPath, const FString& FileName);

bool SlAiJsonHandle::WriteFileWithJsonData(const FString& JsonStr, const FString& RelaPath, const FString& FileName)
{
	if (!JsonStr.IsEmpty())   //字符串是否为空？
	{
		if (!FileName.IsEmpty())   //文件名是否为空？
		{
			FString AbsoPath = FPaths::GameContentDir() + RelaPath + FileName;
			//保存
			if (FFileHelper::SaveStringToFile(JsonStr, *AbsoPath)) 
			{
				return true;
			}
			else 
			{
				SlAiHelper::Debug(FString("Save") + AbsoPath + FString("-->Failed"), 10.f);
			}
		}
	}
	return false;
}

FJsonObject转换为Json格式的字符串

private:
	bool GetFStringInJsonData(const TSharedPtr<FJsonObject>& JsonObj, FString& JsonStr);

bool SlAiJsonHandle::GetFStringInJsonData(const TSharedPtr<FJsonObject>& JsonObj, FString& JsonStr)
{
	if (JsonObj.IsValid() && JsonObj->Values.Num() > 0)
	{
		//写入
		TSharedRef<TJsonWriter<TCHAR>> JsonWriter = TJsonWriterFactory<TCHAR>::Create(&JsonStr);
		FJsonSerializer::Serialize(JsonObj.ToSharedRef(), JsonWriter);
		return true;
	}
	return false;
}

修改存档数据

public:
	//修改存档
	void UpdateRecordData(FString Culture, float MusicVolume, float SoundVolume, TArray<FString>* RecordDataList);


void SlAiJsonHandle::UpdateRecordData(FString Culture, float MusicVolume, float SoundVolume, TArray<FString>* RecordDataList)
{
	//将数据转换为JsonObject
	
	TSharedPtr<FJsonObject> JsonObject = MakeShareable(new FJsonObject);

	TArray<TSharedPtr<FJsonValue>> BaseDataArray;

	//填充数组1.2.3
	TSharedPtr<FJsonObject> CultureObject = MakeShareable(new FJsonObject);
	CultureObject->SetStringField("Culture", Culture);
	TSharedPtr<FJsonValueObject> CultureValue = MakeShareable(new FJsonValueObject(CultureObject));  //转换为JsonValue存入

	TSharedPtr<FJsonObject> MusicVolumeObject = MakeShareable(new FJsonObject);
	MusicVolumeObject->SetNumberField("MusicVolume", MusicVolume);
	TSharedPtr<FJsonValueObject> MusicVolumeValue = MakeShareable(new FJsonValueObject(MusicVolumeObject));

	TSharedPtr<FJsonObject> SoundVolumeObject = MakeShareable(new FJsonObject);
	SoundVolumeObject->SetNumberField("SoundVolume", SoundVolume);
	TSharedPtr<FJsonValueObject> SoundVolumeValue = MakeShareable(new FJsonValueObject(SoundVolumeObject));

	//写入存档名
	TArray<TSharedPtr<FJsonValue>> RecordDataArray;

	for (int i = 0; i < RecordDataList->Num(); ++i) 
	{
		TSharedPtr<FJsonObject> RecordItem = MakeShareable(new FJsonObject);  //转换为JsonValue存入
		RecordItem->SetStringField(FString::FromInt(i), (*RecordDataList)[i]);
		TSharedPtr<FJsonValueObject> RecordDataValue = MakeShareable(new FJsonValueObject(RecordItem));
		RecordDataArray.Add(RecordDataValue);  //添加进数组
	}

	//添加一个key
	TSharedPtr<FJsonObject> RecordDataObject = MakeShareable(new FJsonObject);
	RecordDataObject->SetArrayField("RecordData", RecordDataArray);
	TSharedPtr<FJsonValueObject> RecordDataValue = MakeShareable(new FJsonValueObject(RecordDataObject));

	//添加进数组BaseDataArray
	BaseDataArray.Add(CultureValue);
	BaseDataArray.Add(MusicVolumeValue);
	BaseDataArray.Add(SoundVolumeValue);
	BaseDataArray.Add(RecordDataValue);

	JsonObject->SetArrayField("T", BaseDataArray);

	//将json转为字符串
	FString JsonStr;
	GetFStringInJsonData(JsonObject, JsonStr);

	//SlAiHelper::Debug(FString("Origin Str : " + JsonStr), 60.f);

	//去掉多余字符
	JsonStr.RemoveAt(0, 8);
	JsonStr.RemoveFromEnd(FString("}"));

	//SlAiHelper::Debug(FString("Final Str : " + JsonStr), 60.f);

	//写入文件
	WriteFileWithJsonData(JsonStr, RelativePath, RecordDataFileName);
}

最后当更新数据狗调用

	//更新存档数据                       需要将枚举类型转换为字符串类型(1,UE反射方法，2，普通c++方法)
SlAiSingleton<SlAiJsonHandle>::Get()->UpdateRecordData(GetEnumValueAsString<ECultureTeam>(FString("ECultureTeam"), CurrentCulture),MusicVolume, SoundVolume, &RecordDataList);

来源：CSDN

作者：一个有态度的槛内人

链接：https://blog.csdn.net/weixin_43958768/article/details/104348725