对一个json的字符串进行反编码操作

json字符串要求是"单引号"定义

$jn_city = "{'shandong':'jinan','zhejiang':'hangzhou','liaoning':'shenyang'}";
$fan_city = json_decode($jn_city,true);
var_dump($fan_city);

上面得到的结果为null

$jn_city = '{"shandong":"jinan","zhejiang":"hangzhou","liaoning":"shenyang"}';
$fan_city = json_decode($jn_city,true);
var_dump($fan_city);

上面得到的结果为