Object into a JSON string

Define a Student class:

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

At this point, the new object is directly echo: 1 $person 1 = new Student (' Jack '); 2 echo $person 1;

The result did not print out the object as we expected, but instead reported a fatal error:

An object that is instantiated by the student class cannot be converted to a string, and here is a message: echo must be followed by a string.

Otherwise it will automatically be converted to a string, then how to say an object to a string?

Introduce a Magic method: __tostring (), which is used to respond to a class when it is treated as a string. e.g. echo $obj;

What should be shown. This method must return a string, or a E_RECOVERABLE_ERROR level of fatal error will be emitted.

Add this magic method to the student class:

1 classStudent {2       Public $name;3       Public $age;4      function__construct ($name,$age) {5           $this->name =$name;6           $this->age =$age;7      }8      function__tostring () {9           returnJson_encode ($this, Json_force_object);Ten      } One}

The Json_encode (value, Options) method converts an object to a JSON string, which accepts two parameters.

First parameter: value
The value to encode, in addition to the resource type, can be any data type
This function can only accept UTF-8 encoded data.

Second parameter: Options
A binary mask consisting 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_unicode.

Return value: The success of the encoding returns a string in JSON form or FALSE on failure.

Note: There is a Json_decode method relative to the Json_encode method, which converts a JSON-formatted string into a PHP variable that accepts two parameters

First parameter: JSON string

The second parameter: True/false, True indicates that the string is converted to an object when false, or false when it is a quasi-transposition array.

Return value: Object or Array (when the second argument is true)

At this point in the browser open you can see the conversion success:

Object into a JSON string