Json串：
花括弧表示一个“容器”
方括号装载数组
名称和值用冒号隔开
数组元素通过逗号隔开

JSON示例

{
    "name":"jack",	//常规类型
    "age":18,
    "sub":["a","b"],	//value是数组
    "elp":[ {"a":"A","b":"B"},	//value是一个数组且里面每个元素又是一个json格式
            {"c":"C","d":"D"},
          ]
}

string createJson()
{
	//常规操作
	Document doc;			//生成DOM元素
	doc.SetObject();
	Document::AllocatorType& allocator = doc.GetAllocator();	//生成一个分配器

	//构建键值对
	doc.AddMember("name","jack",allocator);				//键 值 分配器
	doc.AddMember("age", 18, allocator);

	//"sub"
	//构建数组 类型为：["1","2"]
	Value array_sub(kArrayType);						//创建一个数组类型对象
	array_sub.PushBack("a", allocator);
	array_sub.PushBack("b", allocator);

	doc.AddMember("sub", array_sub, allocator);		//将数组分配给sub字段
	//构建数组 类型为：[{"a":"A","b","B"},{"c":"C"}]	一个数组且里面每个元素又是一个json

	//"elp"
	Value array_json(kArrayType);		//一维数组

	Value array_obj1(kObjectType);		//每个数组里又是一个json格式 二级json
	array_obj1.AddMember("a","A",allocator);
	array_obj1.AddMember("b", "B", allocator);
	array_json.PushBack(array_obj1, allocator);

	Value array_obj2(kObjectType);		// 二级json
	array_obj2.AddMember("c", "C", allocator);
	array_obj2.AddMember("d", "D", allocator);
	array_json.PushBack(array_obj2, allocator);
	doc.AddMember("elp", array_json, allocator);

	StringBuffer s;
	Writer<StringBuffer> writer(s);
	doc.Accept(writer);

	return std::string(s.GetString());	
}

//读取json文件
void  ReadJson()
{
	FILE* fp = fopen("..//test.json","rb");
	char readBuffer[65536];
	FileReadStream is(fp, readBuffer, sizeof(readBuffer));
	Document d;
	d.ParseStream(is);
	fclose(fp);

	printf("%s", readBuffer);
}

void writeFiles(string str)			//写入json文件
{
	Document docu;
	string writeJson = str;
	docu.Parse(writeJson.c_str());
	FILE* fp = fopen("..//test.json", "wb");
	char writeBuffer[65535];
	rapidjson::FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer));

	PrettyWriter<FileWriteStream> writer(os);
	docu.Accept(writer);
	fclose(fp);
}

int main()
{
	string result = createJson();
	writeFiles(result);	//写入json文件

	cout << "读取json文件：" << endl;
	ReadJson();

	return 0;
}