PHP json_decode JSON_ERROR_SYNTAX

Question

我尝试从 link 加载和解析 JSON 文件

但我有JSON_ERROR_SYNTAX 的问题和为foreach() 提供的无效参数。为什么会这样？

[{ "Manufacturer": "Toyota", "Sold": 1200, "Month": "2012-11" }, { "Manufacturer": "Ford", "Sold": 1100, "Month": "2012-11" }, { "Manufacturer": "BMW", "Sold": 900, "Month": "2012-11" }, { "Manufacturer": "Benz", "Sold": 600, "Month": "2012-11" }, { "Manufacturer": "GMC", "Sold": 500, "Month": "2012-11" }, { "Manufacturer": "HUMMER", "Sold": 120, "Month": "2012-11" }]

<?php
$url = "http://www.pureexample.com/backend/data/car-sale.json";
$url = file_get_contents($url);
print_r($url);
$url = stripslashes($url);
print_r($url);
$url = str_replace("\n", "", $url);
print_r($url);
$url = iconv('UTF-8', 'UTF-8//IGNORE', utf8_encode($url));
print_r($url);
$url = json_decode($url, true);
// Add this switch to your code
switch (json_last_error())
{
    case JSON_ERROR_NONE:
        echo ' - No errors';
        break;
    case JSON_ERROR_DEPTH:
        echo ' - Maximum stack depth exceeded';
        break;
    case JSON_ERROR_STATE_MISMATCH:
        echo ' - Underflow or the modes mismatch';
        break;
    case JSON_ERROR_CTRL_CHAR:
        echo ' - Unexpected control character found';
        break;
    case JSON_ERROR_SYNTAX:
        echo ' - Syntax error, malformed JSON';
        break;
    case JSON_ERROR_UTF8:
        echo ' - Malformed UTF-8 characters, possibly incorrectly encoded';
        break;
    default:
        echo ' - Unknown error';
        break;
}


foreach($koyim as $data){
echo $data['Manufacturer'];
echo $data['Sold'];
echo $data['Month'];
echo "<br/>";
}
?>

Answer 1

您提供的 link 提供带有字节顺序标记的 UTF-8 格式的 JSON。显然json_decode() 不能很好地处理这三个无关的字符。解决方案是剥离 BOM：

<?php

//see https://stackoverflow.com/a/32185872/500890
function removeBomUtf8($s){
   if(substr($s,0,3)==chr(hexdec('EF')).chr(hexdec('BB')).chr(hexdec('BF'))){
        return substr($s,3);
    }else{
        return $s;
    }
}

$url = "http://www.pureexample.com/backend/data/car-sale.json";
$content = file_get_contents($url);
$clean_content = removeBomUtf8($content);
$decoded = json_decode($clean_content);

//Recovered data
echo "<pre>" . print_r($decoded, TRUE);

我采用此解决方案来剥离 BOM：https://stackoverflow.com/a/32185872/500890，尽管 Internet 上流传着大量此类问题。主要思想是，如果前三个特定字符确实是 BOM，则去掉它们。