rapidjson - change key to another value

问题:

Here is the hello world of rapidjson. How can I change key "hello" to "goodbye" and get string from the json? I mean I want to parse json, change some keys and get json string back like {"goodbye" : "world"}.

const char json[] = "{ \"hello\" : \"world\" }";  rapidjson::Document d; d.Parse<0>(json); 

回答1:

  const char *json = R"({"hello": "world"})";   rapidjson::Document d;   d.Parse<0> (json);    rapidjson::Value::Member* hello = d.FindMember ("hello"); if (hello) {     d.AddMember ("goodbye", hello->value, d.GetAllocator());     d.RemoveMember ("hello");   }    typedef rapidjson::GenericStringBuffer<rapidjson::UTF8<>, rapidjson::MemoryPoolAllocator<>> StringBuffer;   StringBuffer buf (&d.GetAllocator());   rapidjson::Writer<StringBuffer> writer (buf, &d.GetAllocator());   d.Accept (writer);   json = buf.GetString(); 

P.S. You should probably copy the json afterwards because its memory will be freed together with d.

P.P.S. You can also replace the field name in-place, without removing it:

rapidjson::Value::Member* hello = d.FindMember ("hello"); if (hello) hello->name.SetString ("goodbye", d.GetAllocator()); 

Or during iteration:

for (auto it = d.MemberBegin(); it != d.MemberEnd(); ++it)   if (strcmp (it->name.GetString(), "hello") == 0) it->name.SetString ("goodbye", d.GetAllocator()); 

回答2:

In my case there is a key dictionary named keyDict which stores the values that object keys should be replaced with.

std::string line; std::map<std::string, int>  keyDict;  ..................... .........................  rapidjson::Document         doc; doc.Parse<0>(line.c_str()); rapidjson::Value::MemberIterator itr;   for (itr = doc.MemberonBegin(); itr != doc.MemberonEnd(); ++itr) {     std::string keyCode = std::to_string(keyDict[itr->name.GetString()]);     itr->name.SetString(keyCode.c_str(), keyCode.size(), doc.GetAllocator()); } 

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