如何通过PHP的json_encode实现数据格式转换

json_encode() 是 PHP 中用于将数组或对象转换为 JSON 格式的字符串的函数。以下是如何使用 json_encode() 实现数据格式转换的示例：

1. 将关联数组转换为 JSON 字符串：

<?php $assoc_array = array(     "name" => "John",     "age" => 30,     "city" => "New York" );  $json_string = json_encode($assoc_array);  echo $json_string; ?> 

输出：

{"name":"John","age":30,"city":"New York"} 

2. 将多维数组转换为 JSON 字符串：

<?php $multi_dim_array = array(     array(         "name" => "John",         "age" => 30,         "city" => "New York"     ),     array(         "name" => "Jane",         "age" => 28,         "city" => "San Francisco"     ) );  $json_string = json_encode($multi_dim_array);  echo $json_string; ?> 

输出：

[   {"name":"John","age":30,"city":"New York"},   {"name":"Jane","age":28,"city":"San Francisco"} ] 

3. 将对象转换为 JSON 字符串：

<?php class Person {     public $name;     public $age;     public $city;      public function __construct($name, $age, $city) {         $this->name = $name;         $this->age = $age;         $this->city = $city;     } }  $person = new Person("John", 30, "New York");  $json_string = json_encode($person);  echo $json_string; ?> 

输出：

{"name":"John","age":30,"city":"New York"} 

注意：json_encode() 函数在处理特殊字符（如非 ASCII 字符）时可能会返回 null 或抛出警告。为了避免这些问题，可以使用 JSON_UNESCAPED_UNICODE 选项来保留 Unicode 字符：

<?php $json_string = json_encode($assoc_array, JSON_UNESCAPED_UNICODE);  echo $json_string; ?> 

输出：

{"name":"John","age":30,"city":"纽约"}