rapidJson

目前还不知道如何访问，下面类型的数据

[
    {},{}
]

解析字符串

{
    "key":[{},{}]
}

Document doc;
doc.Parse(strConfig.c_str());
ParseErrorCode error(kParseErrorNone);
error = doc.GetParseError();  
if (error != kParseErrorNone)  
{ 
    return;
}
if (!doc.HasMember("dev_th") || !doc["dev_th"].IsArray())
{
    return;
}
Value & arrAlarmHost = doc["dev_th"];
for (int index = 0; index < arrAlarmHost.Size(); ++index)
{
    Value &objDev = arrAlarmHost[index];
    if (!objDev.HasMember("port") || !objDev["port"].IsInt())
    {
        continue;
    }
}

解析对象数组

"defendConfig" :
[
    {
        "addr" : "01234567",
        "defendCode" : "008",
        "name" : "东南角防区"
    },
    {
        "addr" : "7654321",
        "defendCode" : "009",
        "name" : "西南角防区"
    }
]

Document doc;
doc.Parse(m_sCmd.c_str());
ParseErrorCode error(kParseErrorNone);
if (false == doc.HasParseError() &&
    doc.IsArray())
{
    for (size_t i = 0; i < doc.Size(); ++i)
    {
        Value& v = doc[i];
        tagDHFlowCountRegion region;
        region.addr = v["addr"].GetInt();
        region.defendCode = v["defendCode"].GetInt();
        region.strName = v["name"].GetString();
        m_vecConfig.emplace_back(region);
    }
}

构建 json

/*
{
"layout":"2*2",
"Settings":
[
{
"group":"1",
"windows":"1#2",
"cycletime":"10",
"channels":
[
{
"loginID":"1234",
"channel":"2"
}
]
}
]
}
*/
void TestGenerateJsonArray()
{
	string result = "";
	rapidjson::StringBuffer strBuf;
	//rapidjson::Writer<rapidjson::StringBuffer> writer(strBuf);
	rapidjson::PrettyWriter<rapidjson::StringBuffer> writer(strBuf);

	writer.StartObject();
	writer.Key("layout");
	writer.String("2*2");

	
	writer.Key("Settings");
	writer.StartArray();
	writer.StartObject();
	writer.Key("group");
	writer.String("1");
	writer.Key("windows");
	writer.String("1#2");
	writer.Key("cycletime");
	writer.String("10");
	writer.Key("channels");
	writer.StartArray();
	writer.StartObject();
	writer.Key("loginID");
	writer.String("1234");
	writer.Key("channel");
	writer.String("2");
	writer.EndObject();
	writer.EndArray();
	writer.EndObject();
	writer.EndArray();
	writer.EndObject();
	result = strBuf.GetString();
	cout << result << endl;
}

Document docHuminity; // Null
docHuminity.SetArray();
rapidjson::Document::AllocatorType& allocatorHuminity = docHuminity.GetAllocator();
for (auto it = m_mapDevInfo[id_cmd_chan].listChartDataTemperature.begin();it != m_mapDevInfo[id_cmd_chan].listChartDataTemperature.end();++it)
{
    rapidjson::Value obj;
    obj.SetObject();
    obj.AddMember("name",rapidjson::StringRef(it->strName.c_str()),allocatorHuminity);

    rapidjson::Value arr(rapidjson::kArrayType);
    arr.PushBack(rapidjson::StringRef(it->strDatetime.c_str()), allocatorHuminity);
    arr.PushBack(rapidjson::StringRef(it->strValue.c_str()), allocatorHuminity);

    obj.AddMember("value",arr,allocatorHuminity);
    docHuminity.PushBack(obj,allocatorHuminity);
}
rapidjson::StringBuffer bufferH;
rapidjson::Writer<rapidjson::StringBuffer> writerH(bufferH);
docHuminity.Accept(writerH);
strChartHumidity = bufferH.GetString();

对象数组

"value" : 
[
    {
        "addr" : "01234567",
        "defendCode" : "008",
        "name" : "东南角防区"
    },
    {
        "addr" : "7654321",
        "defendCode" : "009",
        "name" : "西南角防区"
    }
]

rapidjson::Document jsonDoc;
rapidjson::Document::AllocatorType &allocator = jsonDoc.GetAllocator(); //获取分配器
//将当前的Document设置为一个object，也就是说，整个Document是一个Object类型的dom元素
jsonDoc.SetObject();
//生成array
rapidjson::Value jsonArr(rapidjson::kArrayType);//创建一个Array类型的元素

for (auto iter = m_vecConfig.begin(); iter != m_vecConfig.end(); ++iter)
{
    string sdev;
    // 构建json字符串

    // 添加属性
    jsonDoc.AddMember("name", iter->strName, allocator);
    jsonDoc.AddMember("addr", iter->strAddr, allocator);
    jsonDoc.AddMember("defendCode", iter->strDefendCode, allocator);
    
    jsonArr.PushBack(jsonDoc, allocator);
}

转字符串

std::string JsonToString(rapidjson::Value& valRoot)
{
    rapidjson::StringBuffer strBuf;
    strBuf.Clear();
    rapidjson::Writer<rapidjson::StringBuffer> writer(strBuf);
    valRoot.Accept(writer);
    std::string strJson = strBuf.GetString();
    return strJson;
}

综合样例

//生成一串如下的json格式字符串，并解析
// {
// "name":"qfl",
// "age":20,
// "letter":["a","b","c"],
// "location": {"province":"fujian","city":"xiamen","number":16}
// "book":[{"name":"book1", "isbn":"123"},{"name":"book2","isbn":"456"}],
// "healthy":true,
// }

//生成Json串
rapidjson::Document jsonDoc;    //生成一个dom元素Document
rapidjson::Document::AllocatorType &allocator = jsonDoc.GetAllocator(); //获取分配器
jsonDoc.SetObject();    //将当前的Document设置为一个object，也就是说，整个Document是一个Object类型的dom元素

//添加属性
jsonDoc.AddMember("name", "qfl", allocator);    //添加字符串值
jsonDoc.AddMember("age", 20, allocator);        //添加int类型值

//生成array
rapidjson::Value letterArray(rapidjson::kArrayType);//创建一个Array类型的元素
letterArray.PushBack("a", allocator);
letterArray.PushBack("b", allocator);
letterArray.PushBack("c", allocator);
jsonDoc.AddMember("letter", letterArray, allocator);    //添加数组

//生成一个object
rapidjson::Value locationObj(rapidjson::kObjectType);//创建一个Object类型的元素
locationObj.AddMember("province", "fujian", allocator);
locationObj.AddMember("city", "xiamen", allocator);
locationObj.AddMember("number", 16, allocator);
jsonDoc.AddMember("location", locationObj, allocator);  //添加object到Document中

//生成一个object数组
rapidjson::Value bookArray(rapidjson::kArrayType);//生成一个Array类型的元素，用来存放Object
rapidjson::Value book1(rapidjson::kObjectType); //生成book1
book1.AddMember("name", "book1", allocator);
book1.AddMember("isbn", "123", allocator);
bookArray.PushBack(book1, allocator);           //添加到数组

rapidjson::Value book2(rapidjson::kObjectType); //生成book2
book2.AddMember("name", "book2", allocator);
book2.AddMember("isbn", "456", allocator);
bookArray.PushBack(book2, allocator);           //添加到数组
jsonDoc.AddMember("book", bookArray, allocator);

//添加属性
jsonDoc.AddMember("healthy", true, allocator);  //添加bool类型值
// jsonDoc.AddMember("sports", NULL, allocator);//添加空值,这里会导致报错

//生成字符串
rapidjson::StringBuffer buffer;
rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
jsonDoc.Accept(writer);

std::string strJson = buffer.GetString();
log("-----生成的Json:\n%s", strJson.c_str());

//写到文件
std::string strPath = FileUtils::getInstance()->getWritablePath() + "JsonFile.txt";
FILE* myFile = fopen(strPath.c_str(), "w");  //windows平台要使用wb
if (myFile) {
    fputs(buffer.GetString(), myFile);
    fclose(myFile);
}

//JsonFile.txt文件内容
//{"name":"qfl","age":20,"letter":["a","b","c"],"location":{"province":"fujian","city":"xiamen","number":16},"book":[{"name":"book1","isbn":"123"},{"name":"book2","isbn":"456"}],"healthy":true}

log("-----读取Json内容:");
//从文件中读取（注意和上面分开，不能确定文件是否生成完毕，这里读取可能有问题）
rapidjson::Document newDoc;
myFile = fopen(strPath.c_str(), "r");   //windows平台使用rb
if (myFile) {
    rapidjson::FileStream inputStream(myFile);  //创建一个输入流
    newDoc.ParseStream<0>(inputStream); //将读取的内容转换为dom元素
    fclose(myFile); //关闭文件，很重要
}
//判断解析从流中读取的字符串是否有错误
if (newDoc.HasParseError()) {
    log("Json Parse error:%d", newDoc.GetParseError()); //打印错误编号
}
else {
    //获取json串中的数据
    //先判断是否有这个字段，如果使用不存在的key去取值会导致直接崩溃
    if (newDoc.HasMember("name")) {
        log("name:%s", newDoc["name"].GetString()); //必须要获取对应的数据类型，rapidjson不会帮你转换类型
    }
    else {}

    if (newDoc.HasMember("age")) {
        log("age:%d", newDoc["age"].GetInt());  //获取正确的类型
    }
    else {}

    if (newDoc.HasMember("letter")) {
        rapidjson::Value letter;    //使用一个新的rapidjson::Value来存放array的内容
        letter = newDoc["letter"];

        //确保它是一个Array，而且有内容
        if (letter.IsArray() && !letter.Empty()) {
            //遍历Array中的内容
            for (rapidjson::SizeType i = 0; i < letter.Size(); i++) {
                log("letter:%s", letter[i].GetString());
            }
        }
        else {}
    }
    else {}

    if (newDoc.HasMember("location")) {
        rapidjson::Value location;      //使用一个新的rapidjson::Value来存放object
        location = newDoc["location"];

        //确保它是一个Object
        if (location.IsObject()) {

            if (location.HasMember("province")) {
                log("location:province:%s", location["province"].GetString());
            }
            else {}
            if (location.HasMember("city")) {
                log("location:city:%s", location["city"].GetString());
            }
            else {}
            if (location.HasMember("number")) {
                log("location:number:%d", location["number"].GetInt());
            }
            else {}
        }
        else {}
    }
    else {}

    //book是一个包含了2个object的array。按照上面的步骤来取值就行
    if (newDoc.HasMember("book")) {
        rapidjson::Value book;
        book = newDoc["book"];

        //先取Array
        if (book.IsArray() && !book.Empty()) {

            rapidjson::Value tempBook;
            for (rapidjson::SizeType i = 0; i < book.Size(); i++) {
                tempBook = book[i]; //Array中每个元素又是一个Object

                if (tempBook.IsObject()) {

                    if (tempBook.HasMember("name") && tempBook.HasMember("isbn")) {
                        log("book:%d:name:%s, isbn:%s", i, tempBook["name"].GetString(), tempBook["isbn"].GetString());
                    }
                    else {}
                }
                else {}
            }
        }
        else {}
    }
    else {}

    if (newDoc.HasMember("healthy")) {
        if (newDoc["healthy"].GetBool()) {
            log("healthy:true");
        }
        else {
            log("healthy:false");
        }
    }
    else {}
}