QByteArray bytes = reply->readAll();     //取出数据
QString str = QString::fromUtf8(bytes);  //解码
qDebug()<<str;                                      //输出
输出结果:
"{\"errNum\":0,\"errMsg\":\"success\",\"retData\":{\"ip\":\"112.238.112.173\",\"country\":\"\\u4e2d\\u56fd\",\"province\":\"\\u5c71\\u4e1c\",\"city\":\"\\u70df\\u53f0\",\"district\":\"\\u798f\\u5c71\",\"carrier\":\"\\u4e2d\\u56fd\\u8054\\u901a\"}}"
我希望得到的数据:
{
    "errNum": 0,
    "errMsg": "success",
    "retData": {
        "ip": "112.238.112.173",
        "country": "中国",
        "province": "山东",
        "city": "烟台",
        "district": "福山",
        "carrier": "中国联通"
    }
}