(PHP 5 >= 5.4.0)
JsonSerializable::jsonSerialize — 指定需要被序列化成 JSON 的数据
序列化物体（Object）成能被 json_encode() 原生地序列化的值。
此函数没有参数。
返回能被 json_encode() 序列化的数据， 这个值可以是除了 resource 外的任意类型。
Example #1 JsonSerializable::jsonSerialize() 例子 returning an array
<?php
class ArrayValue implements JsonSerializable {
public function __construct(array $array) {
$this->array = $array;
}
public function jsonSerialize() {
return $this->array;
}
}
$array = [1, 2, 3];
echo json_encode(new ArrayValue($array), JSON_PRETTY_PRINT);
?>
以上例程会输出：
[
1,
2,
3
]
Example #2 JsonSerializable::jsonSerialize() 例子 返回了一个关联数组 array
<?php
class ArrayValue implements JsonSerializable {
public function __construct(array $array) {
$this->array = $array;
}
public function jsonSerialize() {
return $this->array;
}
}
$array = ['foo' => 'bar', 'quux' => 'baz'];
echo json_encode(new ArrayValue($array), JSON_PRETTY_PRINT);
?>
以上例程会输出：
{
"foo": "bar",
"quux": "baz"
}
Example #3 JsonSerializable::jsonSerialize() 例子 返回一个 integer
<?php
class IntegerValue implements JsonSerializable {
public function __construct($number) {
$this->number = (integer) $number;
}
public function jsonSerialize() {
return $this->number;
}
}
echo json_encode(new IntegerValue(1), JSON_PRETTY_PRINT);
?>
以上例程会输出：
1
Example #4 JsonSerializable::jsonSerialize() 例子 返回一个 string
<?php
class StringValue implements JsonSerializable {
public function __construct($string) {
$this->string = (string) $string;
}
public function jsonSerialize() {
return $this->string;
}
}
echo json_encode(new StringValue('Hello!'), JSON_PRETTY_PRINT);
?>
以上例程会输出：
"Hello!"
benkuhl at gmail dot com (2013-01-31 16:17:40)
A good example on when you would use functionality like this is when working with objects.
json_encode() will take a DateTime and convert it to:
{
"date":"2013-01-31 11:14:05",
"timezone_type":3,
"timezone":"America\/Los_Angeles"
}
This is great when working with PHP, but if the Date is being read by Java. The Java date parser doesn't know what to do with that. But it does know what to do with the ISO8601 format...
<?php
date_default_timezone_set('America/Los_Angeles');
class Fruit implements JsonSerializable {
public
$type = 'Apple',
$lastEaten = null;
public function __construct() {
$this->lastEaten = new DateTime();
}
public function jsonSerialize() {
return [
'type' => $this->type,
'lastEaten' => $this->lastEaten->format(DateTime::ISO8601)
];
}
}
echo json_encode(new Fruit()); //which outputs: {"type":"Apple","lastEaten":"2013-01-31T11:17:07-0500"}
?>