Convert object to JSON string

This article mainly introduces the conversion of objects into JSON strings, which has certain reference value. Now I share it with everyone. Friends in need can refer to it

Define a Student class:

1 class Student {
2     public $name;
3     public $age;
4     function __construct($name, $age) {
5         $this->name = $name;
6         $this->age = $age;
7     }
8 }

At this time, create a new object and echo directly: 1 $person1 = new Student('jack', 20); 2 echo $person1;

The result is not printed as we expected Instead of exiting the object, a fatal error is reported:

means that the object instantiated by the Student class cannot be converted into a string. Here you can get a message: echo It must be followed by a string,

Otherwise it will be automatically converted into a string. So how to convert an object into a string?

First introduce a magic method: __tostring(), this method is used for how a class should respond when it is treated as a string. For example echo $obj;

What should be displayed. This method must return a string, otherwise a E_RECOVERABLE_ERROR level fatal error will be issued.

Add this magic method to the Student class:

 1 class Student { 
 2      public $name; 
 3      public $age; 
 4      function __construct($name, $age) { 
 5           $this->name = $name; 
 6           $this->age = $age; 
 7      } 
 8      function __tostring() { 
 9           return json_encode($this, JSON_FORCE_OBJECT);
 10      }
 11 }

json_encode(value, options) method can convert an object into JSON characters String, this method accepts two parameters,

The first parameter: value
The value to be encoded, except the resource type, can be any data type
This function can only accept UTF- 8 Encoded data

Second parameter: options
Binary mask composed of the following constants: JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT, JSON_UNESCAPED_UNICO DE.

Return value: Returns a string represented in JSON form if the encoding is successful or returns FALSE on failure.

note: Compared with the json_encode method, there is the json_decode method. This method can convert a JSON format string into a PHP variable. This method accepts two parameters

The first parameter: json string

The second parameter: true/false. When it is true, it means transposing the string into an array. When it is false, it means conversion. is an object, the default is false

Return value: object or array (when the second parameter is true)

You can open it in the browser at this time See that the conversion is successful:

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