In this chapter we will introduce how to use PHP language to encode and decode JSON objects.

Environment configuration

JSON extension has been built-in in php5.2.0 and above.

JSON Function

FunctionDescription
json_encode JSON encoding for variables
json_decodeDecode the string in JSON format and convert it into a PHP variable
json_last_errorReturn the last error that occurred

json_encode

PHP json_encode() is used to JSON encode variables , this function returns JSON data if executed successfully, otherwise it returns FALSE.

Syntax

string json_encode ( $value [, $options = 0 ] )

Parameters

  • value: to be encoded value. This function is only valid for UTF-8 encoded data.

  • ##options: 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

Example

The following example demonstrates how to convert a PHP array into JSON format data: 

<?php
   $arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
   echo json_encode($arr);
?>
The result of executing the above code is: 
{"a":1,"b":2,"c":3,"d":4,"e":5}
The following example demonstrates how to convert PHP objects into JSON format data: 
<?php
   class Emp {
       public $name = "";
       public $hobbies  = "";
       public $birthdate = "";
   }
   $e = new Emp();
   $e->name = "sachin";
   $e->hobbies  = "sports";
   $e->birthdate = date('m/d/Y h:i:s a', "8/5/1974 12:20:03 p");
   $e->birthdate = date('m/d/Y h:i:s a', strtotime("8/5/1974 12:20:03"));
   echo json_encode($e);
?>
The execution result of the above code is: 
{"name":"sachin","hobbies":"sports","birthdate":"08\/05\/1974 12:20:03 pm"}
json_decode

PHP json_decode() function is used to decode JSON format strings and convert them into PHP variables.

Syntax

mixed json_decode ($json [,$assoc = false [, $depth = 512 [, $options = 0 ]]])
Parameters

  • json_string: To be decoded JSON string, must be UTF-8 encoded data

  • assoc: When this parameter is TRUE, an array will be returned, and when FALSE, an object will be returned.

  • depth: Parameter of type integer, which specifies the recursion depth

  • options: Binary Mask, currently only JSON_BIGINT_AS_STRING is supported.

Example

The following example demonstrates how to decode JSON data:

<?php
   $json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
   var_dump(json_decode($json));
   var_dump(json_decode($json, true));
?>
The execution result of the above code is:
object(stdClass)#1 (5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}
array(5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}