如何解决json解码返回null错误

Question

我的API URL在浏览器中返回的代码，如下所示。
但 json_decode($api_url,true);返回null。
我检查了一下json_last_error();，它返回4（json错误语法）。
它与json_decode(file_get_contents($api_url),true);
为什么不与json_decode一起工作。请帮忙

{"dataset":{"id":27153572,"dataset_code":"20MICRONS_A_DEBT","database_code":"DEB","name":"20 Microns Limited,Total Debt","description":"\u003cp\u003e20 Microns Limited(NSE:20MICRONS)-Total Debt(Annual)\u003c/p\u003e","refreshed_at":"2018-09-21T08:04:08.278Z","newest_available_date":"2018-03-31","oldest_available_date":"2005-03-31","column_names":["PERIOD","STANDALONE","CONSOLIDATED"],"frequency":"annual","type":"Time Series","premium":true,"limit":null,"transform":null,"column_index":null,"start_date":"2005-03-31","end_date":"2018-03-31","data":[["2018-03-31",128.56,133.68],["2017-03-31",144.9,151.73],["2016-03-31",155.18,163.41],["2015-03-31",152.8,164.62],["2014-03-31",162.01,176.64],["2013-03-31",148.49,164.73],["2012-03-31",144.67,158.6],["2011-03-31",81.42,120.31],["2010-03-31",84.35,87.35],["2009-03-31",58.62,58.62],["2008-03-31",46.52,null],["2007-03-31",42.46,null],["2006-03-31",40.03,null],["2005-03-31",38.98,null]],"collapse":null,"order":null,"database_id":14992}}

Answer 1

您尝试执行的操作没有任何意义。$api_url只是一个网址，因此当您尝试对其进行解码时，它没有json结构，并且会抛出异常。您应该解码的是该URL返回给您的数据。所以首先您应该从url获取数据，然后使用json_decode($api_url,true);。要获取数据，您可以使用file_get_contents或curl。