尝试json_encode对数据进行编码，并设置带有header的content-type (' content-type: application/json');

是的，你需要使用echo来显示输出。Mimetype: application / json

这个问题有很多答案，但没有一个涵盖了返回干净JSON的整个过程，以及防止JSON响应变形所需的一切。

/*
 * returnJsonHttpResponse
 * @param $success: Boolean
 * @param $data: Object or Array
 */
function returnJsonHttpResponse($success, $data)
{
    // remove any string that could create an invalid JSON 
    // such as PHP Notice, Warning, logs...
    ob_clean();

    // this will clean up any previously added headers, to start clean
    header_remove(); 

    // Set the content type to JSON and charset 
    // (charset can be set to something else)
    header("Content-type: application/json; charset=utf-8");

    // Set your HTTP response code, 2xx = SUCCESS, 
    // anything else will be error, refer to HTTP documentation
    if ($success) {
        http_response_code(200);
    } else {
        http_response_code(500);
    }
    
    // encode your PHP Object or Array into a JSON string.
    // stdClass or array
    echo json_encode($data);

    // making sure nothing is added
    exit();
}

引用:

response_remove

ob_clean

JSON内容类型

HTTP规范

http_response_code

json_encode

将域对象格式化为JSON的一种简单方法是使用Marshal Serializer。 然后将数据传递给json_encode，并根据需要发送正确的Content-Type报头。 如果您正在使用Symfony这样的框架，则不需要手动设置标头。在那里您可以使用JsonResponse。

例如，处理Javascript的正确内容类型应该是application/ Javascript。

或者如果你需要支持一些相当老的浏览器，最安全的是文本/javascript。

对于所有其他用途，如移动应用程序，使用application/json作为内容类型。

这里有一个小例子:

<?php
...
$userCollection = [$user1, $user2, $user3];

$data = Marshal::serializeCollectionCallable(function (User $user) {
    return [
        'username' => $user->getUsername(),
        'email'    => $user->getEmail(),
        'birthday' => $user->getBirthday()->format('Y-m-d'),
        'followers => count($user->getFollowers()),
    ];
}, $userCollection);

header('Content-Type: application/json');
echo json_encode($data);

无论何时你试图为API返回JSON响应，或者确保你有适当的标题，也确保你返回一个有效的JSON数据。

下面是示例脚本，它可以帮助您从PHP数组或返回JSON响应 来自JSON文件。

PHP脚本(代码):

<?php

// Set required headers
header('Content-Type: application/json; charset=utf-8');
header('Access-Control-Allow-Origin: *');

/**
 * Example: First
 *
 * Get JSON data from JSON file and retun as JSON response
 */

// Get JSON data from JSON file
$json = file_get_contents('response.json');

// Output, response
echo $json;

/** =. =.=. =.=. =.=. =.=. =.=. =.=. =.=. =.=. =.=. =.  */

/**
 * Example: Second
 *
 * Build JSON data from PHP array and retun as JSON response
 */

// Or build JSON data from array (PHP)
$json_var = [
  'hashtag' => 'HealthMatters',
  'id' => '072b3d65-9168-49fd-a1c1-a4700fc017e0',
  'sentiment' => [
    'negative' => 44,
    'positive' => 56,
  ],
  'total' => '3400',
  'users' => [
    [
      'profile_image_url' => 'http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg',
      'screen_name' => 'rayalrumbel',
      'text' => 'Tweet (A), #HealthMatters because life is cool :) We love this life and want to spend more.',
      'timestamp' => '{{$timestamp}}',
    ],
    [
      'profile_image_url' => 'http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg',
      'screen_name' => 'mikedingdong',
      'text' => 'Tweet (B), #HealthMatters because life is cool :) We love this life and want to spend more.',
      'timestamp' => '{{$timestamp}}',
    ],
    [
      'profile_image_url' => 'http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg',
      'screen_name' => 'ScottMili',
      'text' => 'Tweet (C), #HealthMatters because life is cool :) We love this life and want to spend more.',
      'timestamp' => '{{$timestamp}}',
    ],
    [
      'profile_image_url' => 'http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg',
      'screen_name' => 'yogibawa',
      'text' => 'Tweet (D), #HealthMatters because life is cool :) We love this life and want to spend more.',
      'timestamp' => '{{$timestamp}}',
    ],
  ],
];

// Output, response
echo json_encode($json_var);

JSON文件(JSON数据):

{
    "hashtag": "HealthMatters", 
    "id": "072b3d65-9168-49fd-a1c1-a4700fc017e0", 
    "sentiment": {
        "negative": 44, 
        "positive": 56
    }, 
    "total": "3400", 
    "users": [
        {
            "profile_image_url": "http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg", 
            "screen_name": "rayalrumbel", 
            "text": "Tweet (A), #HealthMatters because life is cool :) We love this life and want to spend more.", 
            "timestamp": "{{$timestamp}}"
        }, 
        {
            "profile_image_url": "http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg", 
            "screen_name": "mikedingdong", 
            "text": "Tweet (B), #HealthMatters because life is cool :) We love this life and want to spend more.", 
            "timestamp": "{{$timestamp}}"
        }, 
        {
            "profile_image_url": "http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg", 
            "screen_name": "ScottMili", 
            "text": "Tweet (C), #HealthMatters because life is cool :) We love this life and want to spend more.", 
            "timestamp": "{{$timestamp}}"
        }, 
        {
            "profile_image_url": "http://a2.twimg.com/profile_images/1285770264/PGP_normal.jpg", 
            "screen_name": "yogibawa", 
            "text": "Tweet (D), #HealthMatters because life is cool :) We love this life and want to spend more.", 
            "timestamp": "{{$timestamp}}"
        }
    ]
}

JSON Screeshot:

返回JSON的完整的PHP代码如下:

$option = $_GET['option'];

if ( $option == 1 ) {
    $data = [ 'a', 'b', 'c' ];
    // will encode to JSON array: ["a","b","c"]
    // accessed as example in JavaScript like: result[1] (returns "b")
} else {
    $data = [ 'name' => 'God', 'age' => -1 ];
    // will encode to JSON object: {"name":"God","age":-1}  
    // accessed as example in JavaScript like: result.name or result['name'] (returns "God")
}

header('Content-type: application/json');
echo json_encode( $data );