C++ ----device-stream-boundary-- Content-Type: application/json Content-Length: 75 X-If-Encrypt: 0 {"type":"response", "seq":0, "params":{"error_code":0, "session_id":"157"}} 字符串解析出session_id

可以使用 JSON 解析库来解析该字符串并获取 session_id。以下是一个使用 RapidJSON 库的示例代码：

#include <iostream>
#include "rapidjson/document.h"

int main() {
    const char* json_str = R"({"type":"response", "seq":0, "params":{"error_code":0, "session_id":"157"}})";

    rapidjson::Document doc;
    doc.Parse(json_str);

    if (!doc.IsObject() || !doc.HasMember("params")) {
        std::cout << "Invalid JSON format!" << std::endl;
        return -1;
    }

    const rapidjson::Value& params = doc["params"];
    if (!params.IsObject() || !params.HasMember("session_id") || !params["session_id"].IsString()) {
        std::cout << "Missing or invalid session_id field!" << std::endl;
        return -1;
    }

    std::string session_id = params["session_id"].GetString();
    std::cout << "Session ID: " << session_id << std::endl;

    return 0;
}

输出结果为：

Session ID: 157