如何在PHP中从给定JSON数据提取longurl字段

别担心，我帮你搞定这个问题！你提供的JSON数据是合法的，大概率是在json_decode的使用细节上出了小问题，下面给你两种可行的方案：

方案1：将JSON解码为PHP对象 #

你可以直接把JSON字符串解码成对象，然后通过对象属性访问的方式获取longurl：

// 你的JSON数据字符串
$jsonData = '{ "success": true, "payment_request": { "id": "3e64d6cbe5ab4829a34845ba69e6f1bb", "phone": "+918562074512", "email": "abcd1@gmail.com", "buyer_name": "just a name", "amount": "10.00", "purpose": "Demo PAID Package", "expires_at": null, "status": "Pending", "send_sms": false, "send_email": true, "sms_status": null, "email_status": "Pending", "shorturl": null, "longurl": "https://test.instamojo.com/@justaname/3e64d6cbe5ab4829a34845ba69e6f1bb", "redirect_url": "http://www.mywebsite.in/exam/Checkouts/Instamojopostpayment/", "webhook": "http://www.example.com/webhook/", "allow_repeated_payments": false, "customer_id": null, "created_at": "2018-05-09T15:05:03.712593Z", "modified_at": "2018-05-09T15:05:03.712614Z" } }';

// 解码为对象
$decodedData = json_decode($jsonData);

// 提取longurl
$longUrl = $decodedData->payment_request->longurl;

// 输出测试
echo $longUrl;

方案2：将JSON解码为关联数组 #

如果你更习惯使用数组操作，可以给json_decode传递第二个参数true，把JSON转成关联数组：

// 同样的JSON数据字符串
$jsonData = '{ "success": true, "payment_request": { "id": "3e64d6cbe5ab4829a34845ba69e6f1bb", "phone": "+918562074512", "email": "abcd1@gmail.com", "buyer_name": "just a name", "amount": "10.00", "purpose": "Demo PAID Package", "expires_at": null, "status": "Pending", "send_sms": false, "send_email": true, "sms_status": null, "email_status": "Pending", "shorturl": null, "longurl": "https://test.instamojo.com/@justaname/3e64d6cbe5ab4829a34845ba69e6f1bb", "redirect_url": "http://www.mywebsite.in/exam/Checkouts/Instamojopostpayment/", "webhook": "http://www.example.com/webhook/", "allow_repeated_payments": false, "customer_id": null, "created_at": "2018-05-09T15:05:03.712593Z", "modified_at": "2018-05-09T15:05:03.712614Z" } }';

// 解码为关联数组
$decodedData = json_decode($jsonData, true);

// 提取longurl
$longUrl = $decodedData['payment_request']['longurl'];

// 输出测试
echo $longUrl;

可能踩坑的地方 #

• 确保你的JSON字符串没有语法错误（你提供的这段是没问题的），如果解码失败可以用json_last_error()查看错误原因。
• 如果JSON是从外部接口获取的，要确保已经正确获取到完整的JSON字符串，没有被截断或者包含多余字符。

内容的提问来源于stack exchange，提问作者Kautuk Bhatnagar