PHP json_decode使用json数组进行查询时返回null

Question

i have this json result

 [{"counter":"542"}]
or 
    [{"counter":"542"},{"counter":"43"}]

and i have the following code

$address = "http://localhost/restauranttheme/syncAndroid/getCounterGenerator4Android.php";
$string = file_get_contents($address);
$json_a = json_decode($string );

but i am getting null result $json_a == null

So what is the problem?

Answer 1

Since you have named the variable $json_a I guess you're expecting an array. If so you may be trying to use an object as an array, which wont work too well. Add a second param (true) to json_decode to return an array instead of an object.

$string = '[{"counter":"542"},{"counter":"43"}]';
$json_a = json_decode($string, true);
// array(2) { [0]=> array(1) { ["counter"]=> string(3) "542" } [1]=> array(1) { ["counter"]=> string(2) "43" } }