c++ - 用jsoncpp解析JSON字符串

我正在尝试解析一个用PHP编码并通过TCP发送到C++客户端的JSON字符串。

我的JSON字符串如下所示:

{"1":{"name":"MIKE","surname":"TAYLOR"},"2":{"name":"TOM","surname":"JERRY"}}

在C++客户端上，我正在使用jsoncpp库:

void decode()
{
    string text =     {"1":{"name":"MIKE","surname":"TAYLOR"},"2":{"name":"TOM","surname":"JERRY"}};
    Json::Value root;
    Json::Reader reader;
    bool parsingSuccessful = reader.parse( text, root );
    if ( !parsingSuccessful )
    {
        cout << "Error parsing the string" << endl;
    }
    const Json::Value mynames = root["name"];
    for ( int index = 0; index < mynames.size(); ++index )
    {
        cout << mynames[index] << endl;
    }
}

问题是我没有得到任何输出，甚至没有关于解析的错误(如果有的话)。
你能帮我了解我做错了什么吗？

最佳答案

您的问题是:没有 root [“name”] 。您的文档应如下所示:

{ "people": [{"id": 1, "name":"MIKE","surname":"TAYLOR"}, {"id": 2, "name":"TOM","surname":"JERRY"} ]}

和你的代码是这样的:

void decode()
{
    string text ="{ \"people\": [{\"id\": 1, \"name\":\"MIKE\",\"surname\":\"TAYLOR\"}, {\"id\": 2, \"name\":\"TOM\",\"surname\":\"JERRY\"} ]}";
    Json::Value root;
    Json::Reader reader;
    bool parsingSuccessful = reader.parse( text, root );
    if ( !parsingSuccessful )
    {
        cout << "Error parsing the string" << endl;
    }

    const Json::Value mynames = root["people"];

    for ( int index = 0; index < mynames.size(); ++index )
    {
        cout << mynames[index] << endl;
    }
}

如果您想按原样保留数据:

void decode()
{
  //string text ="{ \"people\": [{\"id\": 1, \"name\":\"MIKE\",\"surname\":\"TAYLOR\"}, {\"id\": 2, \"name\":\"TOM\",\"surname\":\"JERRY\"} ]}";
  string text ="{ \"1\": {\"name\":\"MIKE\",\"surname\":\"TAYLOR\"}, \"2\": {\"name\":\"TOM\",\"surname\":\"JERRY\"} }";
  Json::Value root;
  Json::Reader reader;
  bool parsingSuccessful = reader.parse( text, root );
  if ( !parsingSuccessful )
  {
    cout << "Error parsing the string" << endl;
  }

  for( Json::Value::const_iterator outer = root.begin() ; outer != root.end() ; outer++ )
  {
    for( Json::Value::const_iterator inner = (*outer).begin() ; inner!= (*outer).end() ; inner++ )
    {
      cout << inner.key() << ": " << *inner << endl;
    }
  }
}

使用迭代器直接遍历根对象(不要将其视为数组。

如果Json::Reader不起作用，请尝试使用Json::CharReader:

void decode()
{
  string text ="{\"1\":{\"name\":\"MIKE\",\"surname\":\"TAYLOR\"},\"2\":{\"name\":\"TOM\",\"surname\":\"JERRY\"}}";

  Json::CharReaderBuilder builder;
  Json::CharReader * reader = builder.newCharReader();

  Json::Value root;
  string errors;

  bool parsingSuccessful = reader->parse(text.c_str(), text.c_str() + text.size(), &root, &errors);
  delete reader;

  if ( !parsingSuccessful )
  {
    cout << text << endl;
    cout << errors << endl;
  }

  for( Json::Value::const_iterator outer = root.begin() ; outer != root.end() ; outer++ )
  {
    for( Json::Value::const_iterator inner = (*outer).begin() ; inner!= (*outer).end() ; inner++ )
    {
      cout << inner.key() << ": " << *inner << endl;
    }
  }
}

关于c++ - 用jsoncpp解析JSON字符串，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/47283908/