PHP无法输出JSON数据问题排查与解决咨询

我帮你排查出两个核心问题，咱们一步步来修复：

1. 修复JSON字符串的语法错误 #

你的$buffer变量末尾多了一个额外的1，这会让整个JSON格式完全失效，json_decode解析后会返回null，自然没法遍历输出内容。

先把这个多余的字符去掉，修正后的$buffer应该是：

$buffer = '[{"isSuccess":"true","message":"Consignment Number Valid","orderReferenceIdList":[":Succesfull"],"tracking_Details":[{"BookingDate":"02-05-2020","Destination":"MANDI BAHAUDDIN","Origin":"LAHORE","Shipper":"VESTURE MERCHANDISING (OTURE)","Consignee":"Syed Asad Abbas Bokhari","ServiceType":"Overnight","CNStatus":"DELIVERED","CNStatusID":"55","pieces":"1","weight":"0.5","Details":[{"DateTime":"5/5/2020 12:03:59 PM","Status":"Delivered","Location":"MANDI BAHAUDDIN","Detail":"Shipment has been Delivered. Delivery Date & Time May 5 2020 1:11AM and Received By: ASAD"},{"DateTime":"5/5/2020 10:03:58 AM","Status":"On Delivery","Location":"MANDI BAHAUDDIN","Detail":"Shipment is Out for Delivery."},{"DateTime":"5/4/2020 10:43:51 AM","Status":"On Delivery","Location":"MANDI BAHAUDDIN","Detail":"Shipment is Out for Delivery."},{"DateTime":"5/4/2020 10:06:57 AM","Status":"Unloading","Location":"MANDI BAHAUDDIN","Detail":"Shipment has arrived at hub."},{"DateTime":"5/4/2020 3:55:10 AM","Status":"Loading","Location":"GUJRANWALA","Detail":"Shipment has departed."},{"DateTime":"5/2/2020 11:20:44 PM","Status":"Unloading","Location":"Lahore Airport","Detail":"Shipment has arrived at hub."},{"DateTime":"5/2/2020 10:40:33 PM","Status":"Loading","Location":"KOT LAKH PAT","Detail":"Shipment has departed."},{"DateTime":"5/2/2020 8:30:52 PM","Status":"Arrived at OPS","Location":"LAHORE","Detail":"Shipment has arrived at origin facility."},{"DateTime":"5/2/2020 12:00:00 AM","Status":"Booking","Location":"LAHORE","Detail":"Shipment is booked."}]}]}]';

2. 修正数组访问的层级错误 #

你的原始JSON是一个包含单个对象的数组，所以json_decode后得到的$data是数组，需要先取索引0的元素，再访问tracking_Details。另外，建议加上解析失败的判断，方便后续调试。

修正后的完整代码：

$buffer = '[{"isSuccess":"true","message":"Consignment Number Valid","orderReferenceIdList":[":Succesfull"],"tracking_Details":[{"BookingDate":"02-05-2020","Destination":"MANDI BAHAUDDIN","Origin":"LAHORE","Shipper":"VESTURE MERCHANDISING (OTURE)","Consignee":"Syed Asad Abbas Bokhari","ServiceType":"Overnight","CNStatus":"DELIVERED","CNStatusID":"55","pieces":"1","weight":"0.5","Details":[{"DateTime":"5/5/2020 12:03:59 PM","Status":"Delivered","Location":"MANDI BAHAUDDIN","Detail":"Shipment has been Delivered. Delivery Date & Time May 5 2020 1:11AM and Received By: ASAD"},{"DateTime":"5/5/2020 10:03:58 AM","Status":"On Delivery","Location":"MANDI BAHAUDDIN","Detail":"Shipment is Out for Delivery."},{"DateTime":"5/4/2020 10:43:51 AM","Status":"On Delivery","Location":"MANDI BAHAUDDIN","Detail":"Shipment is Out for Delivery."},{"DateTime":"5/4/2020 10:06:57 AM","Status":"Unloading","Location":"MANDI BAHAUDDIN","Detail":"Shipment has arrived at hub."},{"DateTime":"5/4/2020 3:55:10 AM","Status":"Loading","Location":"GUJRANWALA","Detail":"Shipment has departed."},{"DateTime":"5/2/2020 11:20:44 PM","Status":"Unloading","Location":"Lahore Airport","Detail":"Shipment has arrived at hub."},{"DateTime":"5/2/2020 10:40:33 PM","Status":"Loading","Location":"KOT LAKH PAT","Detail":"Shipment has departed."},{"DateTime":"5/2/2020 8:30:52 PM","Status":"Arrived at OPS","Location":"LAHORE","Detail":"Shipment has arrived at origin facility."},{"DateTime":"5/2/2020 12:00:00 AM","Status":"Booking","Location":"LAHORE","Detail":"Shipment is booked."}]}]}]';

// 解析JSON并添加错误判断
$data = json_decode($buffer, true);
if (json_last_error() !== JSON_ERROR_NONE) {
    echo 'JSON解析失败：' . json_last_error_msg();
    exit;
}

// 先取数组第一个元素，再遍历tracking_Details
foreach ($data[0]['tracking_Details'] as $a) {
    echo $a['BookingDate']; // 会输出：02-05-2020
}

额外调试技巧 #

以后遇到JSON解析问题，可以用json_last_error()和json_last_error_msg()来快速定位错误，这比盲目调试高效得多。

内容的提问来源于stack exchange，提问作者Matt Berry