php - 类 stdClass 的对象无法转换为字符串错误

Question

我有以下字符串:

{"Coords":[{"Accuracy":"65","Latitude":"53.277720488429026","Longitude":"-9.012038778269686","Timestamp":"Fri Jul 05 2013 11:59:34 GMT+0100 (IST)"},{"Accuracy":"65","Latitude":"53.277720488429026","Longitude":"-9.012038778269686","Timestamp":"Fri Jul 05 2013 11:59:34 GMT+0100 (IST)"},{"Accuracy":"65","Latitude":"53.27770755361785","Longitude":"-9.011979642121824","Timestamp":"Fri Jul 05 2013 12:02:09 GMT+0100 (IST)"},{"Accuracy":"65","Latitude":"53.27769091555766","Longitude":"-9.012051410095722","Timestamp":"Fri Jul 05 2013 12:02:17 GMT+0100 (IST)"},{"Accuracy":"65","Latitude":"53.27769091555766","Longitude":"-9.012051410095722","Timestamp":"Fri Jul 05 2013 12:02:17 GMT+0100 (IST)"}],"Scan":"Whatever"}

我想在 php 中解码。该字符串是通过 sql 查询获得的。见下面的代码:

$TrackDetails_Query= "SELECT * FROM Tracks WHERE TrackID='".$TrackNum."' ORDER BY TrackID DESC";

        $TrackDetails_Result= mysql_query($TrackDetails_Query) or die (mysql_error());

        if (mysql_num_rows($TrackDetails_Result)==0){
                echo 'There are no tracks for the number entered';
            }
        else{
                            $traces=$row['Traces'];
                            $decoded_traces=json_decode($traces);
                            echo $decoded_traces;
            }
    }

但是我得到了错误:

Catchable fatal error: Object of class stdClass could not be converted to string

Answer 1

您收到错误是因为您试图将 stdClass 对象转换为字符串，这是它不支持的。

而不是 echo $decoded_traces 尝试 var_dump($decoded_traces) - 这将给出你解码的对象的诊断 View (我想这就是你想要的).你应该会发现它看起来像这样

class stdClass#1 (2) {
  public $Coords =>
  array(5) {
    [0] =>
    class stdClass#2 (4) {
      public $Accuracy =>
      string(2) "65"
      public $Latitude =>
      string(18) "53.277720488429026"
      public $Longitude =>
      string(18) "-9.012038778269686"
      public $Timestamp =>
      string(39) "Fri Jul 05 2013 11:59:34 GMT+0100 (IST)"
    }
    [1] => (more of the same, edited for brevity)
    [2] =>
    [3] =>
    [4] =>
  }
  public $Scan =>
  string(8) "Whatever"
}

默认情况下，json_encode将像上面那样创建 stdClass 对象。如果您更喜欢关联数组，请将 true 作为第二个参数传递给 json_decode，例如$decoded_traces=json_decode($traces, true);

此外，尽管不能将 stdClass 转换为字符串，但您自己的类可以 - 一个实现了 __toString 的类魔术方法可以转换为字符串!