技术教程 编程教程 Poco::JSON::Array 中object 设置preserveInsertionOrder 时,stringify出错-->深入解析 正文

Poco::JSON::Array 中object 设置preserveInsertionOrder 时,stringify出错-->深入解析

2023-06-14,,

在使用poco version 1.6.0时 Poco::JSON::Array 在object  设置preserveInsertionOrder =true 时

调用 array.stringify出错.

在使用poco::json 输出字符串

    std::string str1 = "\r";

    std::string str2 = "\n";

    Poco::JSON::Object obj1, obj2;

    obj1.set("payload", str1);

    obj2.set("payload", str2);

    std::ostringstream oss1, oss2;

    Poco::JSON::Stringifier::stringify(obj1, oss1);

    Poco::JSON::Stringifier::stringify(obj2, oss2);

    string srxxx=oss1.str()//正常输出...

poco::json::array 输出 字符串:

Object jObj2(true);

    std::string  strValue2="[{\"backspace1\":\"bs2222\",\"1backspace1\":\"1bs2222\"},{\"te1\":\"t1\",\"t2\":\"t2\"}]";

    jObj2.set("car", "这是中文abc@qwe.com1231");

    jObj2.set("baz", "fas");

    std::stringstream ss2222;

    jObj2.stringify(ss2222);

    strxxx.clear();

    strxxx=CMyCodeConvert::Gb2312ToUtf8(ss2222.str());//gbk->utf8

    Object jObj3(true);

    jObj3.set("", "");

    jObj3.set("", "");

    Object jObj4(false);

    jObj4.set("", "");

    jObj4.set("", "");

        Poco::JSON::Array  array1;

        //array1.add(resultxxx);

        array1.add(jObj2);

        array1.add(jObj3);

        array1.add(jObj4);

        //jObj.set("arrar",array1);

        std::stringstream ssArray1;

        Stringifier::stringify(array1,ssArray1);

        //array1.stringify(ssArray1);

        std::string strArray1=ssArray1.str();//->>>>>>输出字符串出错.

but run time is error

追踪代码发现:

\JSON\src\Object.cpp:

Object(bool preserveInsertionOrder = false); //在map 中排序 ,输出时按字母大小顺序.
/// Default constructor. If preserveInsertionOrder, object
/// will preserve the items insertion order. Otherwise, items
/// will be sorted by keys.

preserveInsertionOrder = false 这个我比较反感,因为之前用jsoncpp 处理 某些东东时,因为输出时入 输入的json顺序不 一致  走了不少弯路.

所以  preserveInsertionOrder = true  是我的爱 .

Stringifier::stringify(array1,ssArray1);

----->

JSON\src\Stringifier.cpp:

else if ( any.type() == typeid(Array) )
{
const Array& a = any.extract<Array>();
a.stringify(out, indent == 0 ? 0 : indent, step);
}

--->

if ( any.type() == typeid(Object) )
{
const Object& o = any.extract<Object>();
o.stringify(out, indent == 0 ? 0 : indent, step);
}

--->

\JSON\src\Object.cpp:

void Object::stringify(std::ostream& out, unsigned int indent, int step) const
{
if (step < 0) step = indent;

if(!_preserveInsOrder)
doStringify(_values, out, indent, step);  // 不用代码添加顺序 ,则使用map窗口..jsoncpp也是map
else
doStringify(_keys, out, indent, step);//保留原有代码添加顺序, 则使用 std::deque<Dynamic::Var*> KeyPtrList
}

--->

\Poco\JSON\Object.h

template <typename C>
void doStringify(const C& container, std::ostream& out, unsigned int indent, unsigned int step) const
{
 ....

Stringifier::stringify(getKey(it), out); //这儿   getKey(it), 出了问题
out << ((indent > 0) ? " : " : ":");

Stringifier::stringify(getValue(it), out, indent + step, step);

...

}

\JSON\src\Object.cpp:

const std::string& Object::getKey(KeyPtrList::const_iterator& iter) const
{
ValueMap::const_iterator it = _values.begin();
ValueMap::const_iterator end = _values.end();
for (; it != end; ++it)
{
if (it->second == **iter) return it->first;
}

throw NotFoundException((*iter)->convert<std::string>());  //----->这儿报错
}

--->

Object.cpp中:

void Object::set(const std::string& key, const Dynamic::Var& value)
{
_values[key] = value;
if (_preserveInsOrder)
{
KeyPtrList::iterator it = _keys.begin();
KeyPtrList::iterator end = _keys.end();
for (; it != end; ++it)
{
if (key == **it) return;
}
_keys.push_back(&_values[key]);  //->这儿的内存地址发生了变化.
}
}

示例代码中:

 array1.add(jObj2);　　-->Object 转到 (const Dynamic::Var& value)时

Foundation\include\Poco\Dynamic\Var.h:

Var(const T& val)
/// Creates the Var from the given value.
#ifdef POCO_NO_SOO
: _pHolder(new VarHolderImpl<T>(val))  --->>>发生了拷贝所以内存地址变化了.
{
}

后面在 https://github.com/pocoproject/poco/commit/3553a86d608321c1a06262c721aa766f1808cf2c

作者说

const std::string& Object::getKey(KeyPtrList::const_iterator& iter) const 中

if (&it->second == *iter) return it->first;

改成

if (it->second == **iter) return it->first;

注意 这个==是

poco开发版本地址:

https://github.com/pocoproject/poco/blob/develop/JSON/include/Poco/JSON/Object.h

https://github.com/pocoproject/poco/blob/develop/JSON/src/Object.cpp

以下只贴出了 重要更新的代码.



//

// Object.h

如果是vs08的环境:



inline const Dynamic::Var& Object::getValue(KeyPtrList::const_iterator& it) const
{


return _values.at(**it);  //map.at 是C++ 11的标准,这儿不支持.


}


改成:


inline const Dynamic::Var& Object::getValue(KeyPtrList::const_iterator& it) const
{
 const std::string & strKey=**it;
 ValueMap ::const_iterator iter = _values.find(strKey);
 if(iter!=_values.end())
 return iter->second;


throw NotFoundException(strKey);
}


 


//

// Object.cpp

//

// $Id$

............

void Object::stringify(std::ostream& out, unsigned int indent, int step) const

{

    if (step < ) step = indent;

    if(!_preserveInsOrder)

        doStringify(_values, out, indent, step);

    else

        doStringify(_keys, out, indent, step);

}

const std::string& Object::getKey(KeyPtrList::const_iterator& iter) const

{

    ValueMap::const_iterator it = _values.begin();

    ValueMap::const_iterator end = _values.end();

    for (; it != end; ++it)

    {

        if (it->first == **iter) return it->first;

    }

    throw NotFoundException(**iter);

}

void Object::set(const std::string& key, const Dynamic::Var& value)

{

    std::pair<ValueMap::iterator, bool> ret = _values.insert(ValueMap::value_type(key, value));

    if (_preserveInsOrder)

    {

        KeyPtrList::iterator it = _keys.begin();

        KeyPtrList::iterator end = _keys.end();

        for (; it != end; ++it)

        {

            if (key == **it) return;

        }

        _keys.push_back(&ret.first->first);

    }

}




测试结果:


Object jObj2(true);//-------->use preserveInsertionOrder=true

jObj2.set("car", "这是中文abc@qwe.com1231");

jObj2.set("baz", "fas");

jObj2.set("baz1", "fas");

jObj2.set("1baz11", "fas");

Poco::JSON::Array array1;

array1.add(jObj2);

std::ostringstream oss122;

array1.stringify(oss122);

std::string fdsafsa=oss122.str();

std::cout<<"array1="<<fdsafsa<<std::endl;

//输出:[{"car":"这是中文abc@qwe.com1231","baz":"fas","baz1":"fas","1baz11":"fas"}]


　　本以为到这儿就已经结束了....


　　然而我错了...


　　上篇附笔中:


　　poco json 中文字符，抛异常JSON Exception -->iconv 转换 备忘录。


　　http://www.cnblogs.com/bleachli/p/4646092.html


　　中的 suite()作下改变:


　　


std::string  suite()

{

    std::string json = "";

        //"{"

        //"\"id\": 1123,"

        //"\"jsonrpc\": \" 123.abc@hello.com,大圣归来.. \","

        //"\"total\": 2,"

        //"\"result\": "

        //"["

        //"{"

        //"\"id\": null,"

        //"\"picture\": \"http://placehold.it/32x32\","

        //"\"name\": \"这是中文测试.Crossman\","

        //"\"about\": \"《西游记之大圣归来》是根据中国传统神话故事进行拓展和演绎的3D动画电影.xxxx Consectetuer suscipit volutpat eros dolor .\","

        //"\"friends\": "

        //"["

        //"{"

        //"},"

        //"{"

        //"\"id\": 2,"

        //"\"name\": \"Bailey Oldridge2\""

        //"},"

        //"{"

        //"\"id\": 3,"

        //"\"name\": \"Makayla Campbell3\""

        //"}"

        //"]"

        //"},"

        //"{"

        //"\"id\": 2,"

        //"\"picture\": \"http://placehold.it/32x32\","

        //"\"name\": \"2中名 欢迎 \","

        //"\"about\": \"2北京你好 dolor .\","

        //"\"friends\": "

        //"["

        //"]"

        //"}"

        //"]"

        //"}";

    std::string strUtf8=GetJsonSource(true);

    Parser parser;

    Var result;

    try

    {

        result = parser.parse(strUtf8);//json转换...

    }

    catch(JSONException& jsone)

    {

        std::cout << jsone.message() << std::endl;

        return "result==NULL";

    }

    Object::Ptr object = result.extract<Object::Ptr>();

    int nObjectSize=object->size();

    //assert(object->size() > 0);

    DynamicStruct ds = *object;

    //遍历...

    for(DynamicStruct::Iterator  itBegin=ds.begin();itBegin!=ds.end();itBegin++)

    {

        //std::string strvalue=itBegin;

        //Var var= itBegin->second;

        //std::cout<<"type:"<<var.type()<<std::endl;

        std::cout<<"K:"  << itBegin->first << " , value: " <<CMyCodeConvert::Utf8ToGb2312( itBegin->second.toString()) << std::endl;

    }

    std::cout<<std::endl<<std::endl<<std::endl;

    std::cout<<"+++++++++++++++++++++++++++++++++++++++++++++++++++"<<std::endl;

    json="";

    std::string strlation1xxxx;

    std::string strjstostring=strUtf8;

    std::string strTemp;

    std::string strKey;

    //std::string strKey="id";

    //key 是否存在

    strKey="id";

    if(object->has(strKey))

    {

        strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

        std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

    }

    strKey="id2232";

    if(object->has(strKey))

    {

        strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

        std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

    }

    strKey="jsonrpc";

    if(object->has(strKey))

    {

        strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

        std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

        std::string strxxx;

        std::cout<<"jsonrpc 编码:"<<std::endl;

        std::string strxxxx=strTemp;

        for(int nxxx=;nxxx<strxxxx.size();++nxxx)

        {

            unsigned char chTemp=strxxxx[nxxx];

            std::string strTemp=Poco::format("%hX",(unsigned short )chTemp);

            strTemp+=" ";

            //std::cout<<strTemp;

        }

        std::cout<<std::endl;

        //strjstostring+=strTemp;

        std::cout<<"object333->get("<<strKey<<")="<<strTemp<<std::endl;

    }

    strKey="total";

    if(object->has(strKey))

    {

        strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

        std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

    }

    strKey="result";

    if(object->has(strKey))

    {

        strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

        std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

        Var  vResult=object->get("result");

        Poco::JSON::Array::Ptr arrayResult = object->getArray("result");

        Poco::JSON::Array::Ptr arr22222 = vResult.extract<Poco::JSON::Array::Ptr>();

        Poco::Dynamic::Array dsarrayResult = *arrayResult;

        std::cout<<"arr22222->size()"<<arr22222->size()<<std::endl;

        std::cout<<"arrayResult->size()"<<arrayResult->size()<<std::endl;

        std::cout<<"arrayResult->size()"<<dsarrayResult.size()<<std::endl;

        for(int nIndex=;nIndex<arrayResult->size();++nIndex)

        {

            Object::Ptr object = arrayResult->getObject(nIndex);

            strKey="id";

            if(object->has(strKey))

            {

                strTemp="";

                if(!object->get(strKey).isEmpty())

                {

                    strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

                    std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

                }

            }

            strKey="picture";

            if(object->has(strKey))

            {

                strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

                std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

            }

            strKey="name";

            if(object->has(strKey))

            {

                strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

                std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

            }

            strKey="about";

            if(object->has(strKey))

            {

                strTemp=CMyCodeConvert::Utf8ToGb2312( object->get(strKey).toString());

                std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

            }

            strKey="friends";

            if(object->has(strKey))

            {

                strTemp=object->get(strKey).toString();

                std::cout<<"object->get("<<strKey<<")="<<strTemp<<std::endl;

                Poco::JSON::Array::Ptr arrayFriends = object->getArray(strKey);

                for(int nIndex=;nIndex<arrayFriends->size();++nIndex)

                {

                    Object::Ptr objectFriends = arrayFriends->getObject(nIndex);

                    DynamicStruct dsTemp = *objectFriends;

                    for(DynamicStruct::Iterator  itBegin=dsTemp.begin();itBegin!=dsTemp.end();itBegin++)

                    {

                        std::cout<<"K:"  << itBegin->first << " , value: " << CMyCodeConvert::Utf8ToGb2312(itBegin->second.toString() )<< std::endl;

                    }

                }

            }

            std::cout<<std::endl<<std::endl<<std::endl;

            std::cout<<"+++++++++++++++++++++++++++++++++++++++++++++++++++"<<std::endl;

            std::cout<<std::endl<<std::endl<<std::endl;

        }

    }

    return strjstostring;

}


GetJsonSource()代码:


std::string GetJsonSource(bool bUtf8)

{

    bool bIspreserveInsertionOrder=true;

    Object jObjRoot(bIspreserveInsertionOrder);//-------->use preserveInsertionOrder=true

    jObjRoot.set("id", );

    jObjRoot.set("car",  ("这是中文abc@qwe.com1231,123.abc@hello.com,大圣归来..") );

    jObjRoot.set("total", );

    Poco::JSON::Array arrayResult;

    for(int nIndex=;nIndex<;nIndex++)

    {

        Object jArrayObj(bIspreserveInsertionOrder);

        jArrayObj.set("id", nIndex);

        jArrayObj.set("picture",("http://placehold.it/111.abc.") );

        jArrayObj.set("name",("这是中文测试.Crossman.") );

        jArrayObj.set("about",("《西游记之大圣归来》是根据中国传统神话故事进行拓展和演绎的3D动画电影.xxxx Consectetuer suscipit volutpat eros dolor .") );

        Poco::JSON::Array arrayFriends;

        for(int i=;i<;++i)

        {

            Object jarrayFriendsObj(bIspreserveInsertionOrder);

            jarrayFriendsObj.set("id", i);

            jarrayFriendsObj.set("name", (Poco::format("name%d,这是无可奈何花落去!",i)));

            arrayFriends.add(jarrayFriendsObj);

        }

        jArrayObj.set("friends",arrayFriends);

        arrayResult.add(jArrayObj);

    }

    jObjRoot.set("result",arrayResult);

    std::string strObjRoot;

    std::ostringstream ojObjRoot;

    //

    //bIspreserveInsertionOrder =false时程序正常运行.

    //bIspreserveInsertionOrder =true 时程序出错

    //Poco\JSON\Object.cpp

    //const std::string& Object::getKey(KeyPtrList::const_iterator& iter) const

    //iter is null.

    //产生memcpy 错误..

    //

    jObjRoot.stringify(ojObjRoot);//



    strObjRoot=ojObjRoot.str();

    if(bUtf8)

        strObjRoot=CMyCodeConvert::Gb2312ToUtf8(strObjRoot);

    //std::string strGbkTemp=CMyCodeConvert::Utf8ToGb2312(strObjRoot);

    return strObjRoot;

}


原因是


typedef std::deque<const std::string*> KeyPtrList; 这儿是指针地址,临时变量内容已经over了.


so...再改改代码:


poco\JSON\include\Poco\JSON\Object.h 改动部分


typedef std::deque< std::string> KeyPtrList;

inline const Dynamic::Var& Object::getValue(KeyPtrList::const_iterator& it) const

{

const std::string & strKey=*it;

ValueMap ::const_iterator iter = _values.find(strKey);

if(iter!=_values.end())

return iter->second;

throw NotFoundException(strKey);

}


poco\JSON\src\Object.cpp 中改动部分:


const std::string& Object::getKey(KeyPtrList::const_iterator& iter) const

{

ValueMap::const_iterator it = _values.begin();

ValueMap::const_iterator end = _values.end();

for (; it != end; ++it)

{

if (it->first == *iter) return it->first;

}

throw NotFoundException(*iter);

}

void Object::set(const std::string& key, const Dynamic::Var& value)

{

std::pair<ValueMap::iterator, bool> ret = _values.insert(ValueMap::value_type(key, value));

if (_preserveInsOrder)

{

KeyPtrList::iterator it = _keys.begin();

KeyPtrList::iterator end = _keys.end();

for (; it != end; ++it)

{

if (key == *it) return;

}

_keys.push_back(ret.first->first);

}

}


　　


　　GetJsonSource()输出的结果可在 http://www.bejson.com/  中校验.


　　-_- 终于成功了...


　　


　　把代码在debian下编译看下 通过http访问结果:


　　


然而作者又回复了我:


Don't nest objects and arrays by value, it won't work properly - use smart pointers (Object::Ptr and Array::Ptr). See this issue for explanation.


object.h,object.cpp还是用作者的code.


poco开发版本地址:


https://github.com/pocoproject/poco/blob/develop/JSON/include/Poco/JSON/Object.h


https://github.com/pocoproject/poco/blob/develop/JSON/src/Object.cpp


然后测试代码如下:


std::string GetJsonSource(bool bUtf8)

{

    bool bIspreserveInsertionOrder=true;

    //Object result(bIspreserveInsertionOrder);//-------->use preserveInsertionOrder=true

    //result.set("id", 1123);

    //Poco::JSON::Object::Ptr  inner= new Poco::JSON::Object(bIspreserveInsertionOrder) ;

    //inner->set("some_number", 5);

    //inner->set("some_string", "xyz");

    //std::string key = "new_object";

    //result.set(key, inner); // OK

    ////assert (result.isObject()); // OK

    //

    //std::string strOxxxxx;

    //std::ostringstream oxxxxx;

    //result.stringify(oxxxxx);//

    //strOxxxxx=oxxxxx.str();

    //return "";

    Object jObjRoot(bIspreserveInsertionOrder);//-------->use preserveInsertionOrder=true

    jObjRoot.set("id", );

    jObjRoot.set("car",  ("这是中文abc@qwe.com1231,123.abc@hello.com,大圣归来..") );

    jObjRoot.set("total", );

    //Poco::JSON::Array arrayResult;

    Poco::JSON::Array::Ptr  parrayResult= new Poco::JSON::Array() ;

    for(int nIndex=;nIndex<;nIndex++)

    {

        Poco::JSON::Object::Ptr  pjArrayObj= new Poco::JSON::Object(bIspreserveInsertionOrder) ;

        //Object jArrayObj(bIspreserveInsertionOrder);

        pjArrayObj->set("id", nIndex);

        pjArrayObj->set("picture",("http://placehold.it/111.abc.") );

        pjArrayObj->set("name",("这是中文测试.Crossman.") );

        pjArrayObj->set("about",("《西游记之大圣归来》是根据中国传统神话故事进行拓展和演绎的3D动画电影.xxxx Consectetuer suscipit volutpat eros dolor .") );

        Poco::JSON::Array::Ptr  parrayFriends= new Poco::JSON::Array() ;

        //Poco::JSON::Array arrayFriends;

        for(int i=;i<;++i)

        {

            Poco::JSON::Object::Ptr  pjarrayFriendsObj= new Poco::JSON::Object(bIspreserveInsertionOrder) ;

            //Object jarrayFriendsObj(bIspreserveInsertionOrder);

            pjarrayFriendsObj->set("id", i);

            pjarrayFriendsObj->set("name", (Poco::format("name%d,这是无可奈何花落去!",i)));

            parrayFriends->add(pjarrayFriendsObj);

        }

        pjArrayObj->set("friends",parrayFriends);

        parrayResult->add(pjArrayObj);

    }

    jObjRoot.set("result",parrayResult);

    std::string strObjRoot;

    std::ostringstream ojObjRoot;

    ////

    jObjRoot.stringify(ojObjRoot);//

    strObjRoot=ojObjRoot.str();

    if(bUtf8)

        strObjRoot=CMyCodeConvert::Gb2312ToUtf8(strObjRoot);

    //std::string strGbkTemp=CMyCodeConvert::Utf8ToGb2312(strObjRoot);

    return strObjRoot;

}


这个问题终于得到解决...


Poco::JSON::Array 中object 设置preserveInsertionOrder 时,stringify出错-->深入解析的相关教程结束。








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