c++ - 通过使用boost属性树解析JSON文件来访问 bool 值

Question

下面是我从JSON文件获取值的步骤:

{
  "Bases":[
    {
      "mnemonic":"ADIS.LA.01",
      "relay":true
    },
    {
      "mnemonic":"ALEX.LA.01",
      "relay":true
    }
  ]
}

我无法获取 bool(boolean) 值。

在下面的代码中，我是:

打开JSON文件

设置根元素并开始遍历此根元素下的子树(基本)

获取每个标签的值并将其保存为适当的变量类型。

码:

ReadJsonFile()
{
    using boost::property_tree::ptree;
    const boost::property_tree::ptree& propTree
    boost::property_tree::read_json(ss, pt);
    const std::string rootElement = "Bases"; 
    boost::property_tree::ptree childTree;
    bool m_relay;
    try
    {
        /** get_child - Get the child at the given path, or throw @c ptree_bad_path. */
        childTree = propTree.get_child(rootElement);
    }
    catch (boost::property_tree::ptree_bad_path& ex)
    {
        return false;
    }

    BOOST_FOREACH(const boost::property_tree::ptree::value_type &v, propTree.get_child(rootElement)){
       string vID;
       for (ptree::const_iterator subTreeIt = v.second.begin(); subTreeIt != v.second.end(); ++subTreeIt) {
          if (subTreeIt->first == "mnemonic")
          {
             // Get the value string and trim the extra spaces, if any
             vID = boost::algorithm::trim_copy( subTreeIt->second.data() );
          }
          if (subTreeIt->first == "relay")
          {
            m_relay = boost::algorithm::trim_copy(subTreeIt->second.data());
          }
       }
    }
 }

错误:

error: cannot convert ‘std::basic_string<char, std::char_traits<char>, std::allocator<char> >’ to ‘bool’ in assignment

显然， bool(boolean) 值"relay":true被视为字符串而不是bool。

如果我改变

bool m_relay;

至

std::string m_relay;

该代码可以正常工作，但是bool类型无法编译。

我想念什么吗？

Answer 1

尝试使用此:

m_relay = subTreeIt->second.get_value<bool>();

代替这个:

m_relay = boost::algorithm::trim_copy(subTreeIt->second.data());