Hướng dẫn object to json php

Question

Chuyển array thành json string

Array thành json string

$user = [
    'id' => 1,
    'username' => 'admin',
];

echo json_encode($user);

Kết quả:

Nội dung chính Show

Chuyển array thành json string
Array thành json string
Chuyển ngược lại json string thành array
Chuyển Object thành json string
Description
Return Values

{"id":1,"username":"admin"}

Nếu muốn format đẹp hơn ta cho thêm tham số:

echo json_encode($user, JSON_PRETTY_PRINT);

Kết quả:

{
    "id": 1,
    "username": "admin"
}

Chuyển ngược lại json string thành array

Cách thực hiện đơn giản như sau:

$json = '{"id":1,"username":"admin"}';
$user = json_decode($json, true);

Tham số thứ 2 true của hàm json_decode là để hàm trả về kết quả là array.

Chuyển Object thành json string

Encode

Ta giả sử có class user như sau:

class User {
    public $id;
    public $username;
}

Sử dụng class như sau:

$user = new User();
$user->id = 1;
$user->username = 'admin';

echo json_encode($user);

Ta cũng sẽ được kết quả tương tự như trên:

`{"id":1,"username":"admin"}

Decode

Vậy làm sao để decode được json to object của class User Có khá nhiều cách nhưng cách đơn giản và hiệu quả nhất như sau:

// Khai báo class
class User {
    public $id;
    public $username;
}

// json string
$json = '{"id":1,"username":"admin"}';

// thực hiện decode như ở trên
$data = json_decode($json, true);

// tạo object User
$user = new User();

// Gắn dữ liệu vào object User
foreach ($data as $key => $value) {
    $user->{$key} = $value;
}

// Thu được kết quả
var_export($user);

Kết quả:

User::__set_state(array(
   'id' => 1,
   'username' => 'admin',
))

---

Phuc Tran Hoang

(PHP 5 >= 5.2.0, PHP 7, PHP 8, PECL json >= 1.2.0)

json_encode — Returns the JSON representation of a value

Description

json_encode(mixed $value, int $flags = 0, int $depth = 512): string|false

If a value to be serialized is an object, then by default only publicly visible properties will be included. Alternatively, a class may implement JsonSerializable to control how its values are serialized to JSON.

The encoding is affected by the supplied flags and additionally the encoding of float values depends on the value of serialize_precision.

Parameters

value

The value being encoded. Can be any type except a resource.

All string data must be UTF-8 encoded.

Note:
PHP implements a superset of JSON as specified in the original » RFC 7159.

flags

Bitmask consisting of JSON_FORCE_OBJECT, JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_INVALID_UTF8_IGNORE, JSON_INVALID_UTF8_SUBSTITUTE, JSON_NUMERIC_CHECK, JSON_PARTIAL_OUTPUT_ON_ERROR, JSON_PRESERVE_ZERO_FRACTION, JSON_PRETTY_PRINT, JSON_UNESCAPED_LINE_TERMINATORS, JSON_UNESCAPED_SLASHES, JSON_UNESCAPED_UNICODE, JSON_THROW_ON_ERROR. The behaviour of these constants is described on the JSON constants page.

depth

Set the maximum depth. Must be greater than zero.

Return Values

Returns a JSON encoded string on success or false on failure.

Changelog

Version	Description
7.3.0	`JSON_THROW_ON_ERROR` `flags` was added.
7.2.0	`JSON_INVALID_UTF8_IGNORE`, and `JSON_INVALID_UTF8_SUBSTITUTE` `flags` were added.
7.1.0	`JSON_UNESCAPED_LINE_TERMINATORS` `flags` was added.
7.1.0	serialize_precision is used instead of precision when encoding double values.

Examples

Example #1 A json_encode() example

$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);

echo

json_encode($arr);
?>

The above example will output:

{"a":1,"b":2,"c":3,"d":4,"e":5}

Example #2 A json_encode() example showing some flags in use

$a = array('',"'bar'",'"baz"','&blong&', "\xc3\xa9");

echo

"Normal: ",  json_encode($a), "\n";
echo "Tags: ",    json_encode($a, JSON_HEX_TAG), "\n";
echo "Apos: ",    json_encode($a, JSON_HEX_APOS), "\n";
echo "Quot: ",    json_encode($a, JSON_HEX_QUOT), "\n";
echo "Amp: ",     json_encode($a, JSON_HEX_AMP), "\n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ",     json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";$b = array();echo"Empty array output as array: ", json_encode($b), "\n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "\n\n";$c = array(array(1,2,3));echo"Non-associative array output as array: ", json_encode($c), "\n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "\n\n";$d = array('foo' => 'bar', 'baz' => 'long');echo"Associative array always output as object: ", json_encode($d), "\n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";
?>

The above example will output:

Normal: ["","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]

Empty array output as array: []
Empty array output as object: {}

Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}

Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}

Example #3 JSON_NUMERIC_CHECK option example

echo "Strings representing numbers automatically turned into numbers".PHP_EOL; $numbers = array('+123123', '-123123', '1.2e3', '0.00001'); var_dump( $numbers, json_encode($numbers, JSON_NUMERIC_CHECK) ); echo "Strings containing improperly formatted numbers".PHP_EOL; $strings = array('+a33123456789', 'a123'); var_dump( $strings, json_encode($strings, JSON_NUMERIC_CHECK) ); ?>

The above example will output something similar to:

Strings representing numbers automatically turned into numbers
array(4) {
  [0]=>
  string(7) "+123123"
  [1]=>
  string(7) "-123123"
  [2]=>
  string(5) "1.2e3"
  [3]=>
  string(7) "0.00001"
}
string(28) "[123123,-123123,1200,1.0e-5]"
Strings containing improperly formatted numbers
array(2) {
  [0]=>
  string(13) "+a33123456789"
  [1]=>
  string(4) "a123"
}
string(24) "["+a33123456789","a123"]"

Example #4 Sequential versus non-sequential array example

echo "Sequential array".PHP_EOL; $sequential = array("foo", "bar", "baz", "blong"); var_dump( $sequential, json_encode($sequential) );

echo

PHP_EOL."Non-sequential array".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
var_dump(
 $nonsequential,
 json_encode($nonsequential)
);echoPHP_EOL."Sequential array with one key unset".PHP_EOL;
unset($sequential[1]);
var_dump(
 $sequential,
 json_encode($sequential)
);
?>

The above example will output:

Sequential array
array(4) {
  [0]=>
  string(3) "foo"
  [1]=>
  string(3) "bar"
  [2]=>
  string(3) "baz"
  [3]=>
  string(5) "blong"
}
string(27) "["foo","bar","baz","blong"]"

Non-sequential array
array(4) {
  [1]=>
  string(3) "foo"
  [2]=>
  string(3) "bar"
  [3]=>
  string(3) "baz"
  [4]=>
  string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":"blong"}"

Sequential array with one key unset
array(3) {
  [0]=>
  string(3) "foo"
  [2]=>
  string(3) "baz"
  [3]=>
  string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"

Example #5 JSON_PRESERVE_ZERO_FRACTION option example

var_dump(json_encode(12.0, JSON_PRESERVE_ZERO_FRACTION)); var_dump(json_encode(12.0)); ?>

The above example will output:

string(4) "12.0"
string(2) "12"

Notes

Note:
In the event of a failure to encode, json_last_error() can be used to determine the exact nature of the error.

Note:
When encoding an array, if the keys are not a continuous numeric sequence starting from 0, all keys are encoded as strings, and specified explicitly for each key-value pair.

Note:
Like the reference JSON encoder, json_encode() will generate JSON that is a simple value (that is, neither an object nor an array) if given a string, int, float or bool as an input value. While most decoders will accept these values as valid JSON, some may not, as the specification is ambiguous on this point.
To summarise, always test that your JSON decoder can handle the output you generate from json_encode().

I came across the "bug" where running json_encode() over a SimpleXML object was ignoring the CDATA. I ran across http://bugs.php.net/42001 and http://bugs.php.net/41976, and while I agree with the poster that the documentation should clarify gotchas like this, I was able to figure out how to workaround it.

You need to convert the SimpleXML object back into an XML string, then re-import it back into SimpleXML using the LIBXML_NOCDATA option. Once you do this, then you can use json_encode() and still get back the CDATA.

// Pretend we already have a complex SimpleXML object stored in $xml $json = json_encode(new SimpleXMLElement($xml->asXML(), LIBXML_NOCDATA)); ?>

Nick ¶

6 years ago

Please note that there was an (as of yet) undocumented change to the json_encode() function between 2 versions of PHP with respect to JSON_PRETTY_PRINT:

In version 5.4.21 and earlier, an empty array [] using JSON_PRETTY_PRINT would be rendered as 3 lines, with the 2nd one an empty (indented) line, i.e.: "data": [

],

In version 5.4.34 and above, an empty array [] using JSON_PRETTY_PRINT would be rendered as exactly [] at the spot where it occurs, i.e. "data: [],

This is not mentioned anywhere in the PHP changelist and migration documentations; neither on the json_encode documentation page.

This is very useful to know when you are parsing the JSON using regular expressions to manually insert portions of data, as is the case with my current use-case (working with JSON exports of over several gigabytes requires sub-operations and insertion of data).

guilhenfsu at gmail dot com ¶

9 years ago

Solution for UTF-8 Special Chars.

$array = array('nome'=>'Paição','cidade'=>'São Paulo');

$array = array_map('htmlentities',$array);

//encode $json = html_entity_decode(json_encode($array));

//Output: {"nome":"Paição","cidade":"São Paulo"} echo $json;

?>


 ck at
ergovia dot de ¶
9 years ago

Attention when passing a plain array to json_encode and using JSON_FORCE_OBJECT. It figured out that the index-order of the resulting JSON-string depends on the system PHP is running on.
$a = array("a" , "b", "c");
echo json_encode($a, JSON_FORCE_OBJECT);
On Xampp (Windows) you get:
{"0":"a","1":"b","2":"c"}';
On a machine running debian I get:
{"2":"a","1":"b","0":"c"}';
Note that the key:value pairs are different!
Solution here was to use array_combine to create a ssociative array and then pass it to json_encode:
json_encode(array_combine(range(0, count($a) - 1), $a), JSON_FORCE_OBJECT);

 Walter Tross ¶
6 years ago

If you need pretty-printed output, but want it indented by 2 spaces instead of 4:
$json_indented_by_4 = json_encode($output, JSON_UNESCAPED_SLASHES|JSON_PRETTY_PRINT);
$json_indented_by_2 = preg_replace('/^(  +?)\\1(?=[^ ])/m', '$1', $json_indented_by_4);

 Istratov Vadim ¶
13 years ago

Be careful with floating values in some locales (e.g. russian) with comma (",") as decimal point. Code:




setlocale(LC_ALL, 'ru_RU.utf8');
$arr = array('element' => 12.34);

echo json_encode( $arr );

?>



Output will be:

--------------

{"element":12,34}

--------------

Which is NOT a valid JSON markup. You should convert floating point variable to strings or set locale to something like "LC_NUMERIC, 'en_US.utf8'" before using json_encode.


jakepucan at gmail dot com ¶
1 year ago

It's also  worth mentioning that adding charset is fine.
header('Content-type:application/json;charset=utf-8');
json_encode(['name' => 'Jake', 'country' => 'Philippines']);

 Sam Barnum ¶
13 years
ago

Note that if you try to encode an array containing non-utf values, you'll get null values in the resulting JSON string.  You can batch-encode all the elements of an array with the array_map function:
$encodedArray = array_map(utf8_encode, $rawArray);
?>

 spam.goes.in.here AT gmail.com ¶
14 years ago

For anyone who has run into the problem of private properties not being added, you can simply implement the IteratorAggregate interface with the getIterator() method. Add the properties you want to be included in the output into an array in the getIterator() method and return it.
 Garrett ¶
13 years ago

A note about json_encode automatically quoting numbers:
It appears that the json_encode function pays attention to the data type of the value. Let me explain what we came across:
We have found that when retrieving data from our database, there are occasions when numbers appear as strings to json_encode which results in double quotes around the values.
This can lead to problems within javascript functions expecting the values to be numeric.
This was discovered when were were retrieving fields from the database which contained serialized arrays. After unserializing them and sending them through the json_encode function the numeric values in the original array were now being treated as strings and showing up with double quotes around them.
The fix: Prior to encoding the array, send it to a function which checks for numeric types and casts accordingly. Encoding from then on worked as expected.

 pvl dot kolensikov at gmail dot
com ¶
11 years ago

As json_encode() is recursive, you can use it to serialize whole structure of objects.

class A {

    public $a = 1;

    public $b = 2;

    public $collection = array();

    function
__construct(){

        for ( $i=3; $i-->0;){

            array_push($this->collection, new B);

        }

    }

}

class B {

    public $a = 1;

    public $b = 2;

}

echo json_encode(new A);

?>



Will give:

{

    "a":1,

    "b":2,

    "collection":[{

        "a":1,

        "b":2

    },{

        "a":1,

        "b":2

    },{

        "a":1,

        "b":2

    }]

}
 mikko dot rantalainen at peda dot net ¶
1 year
ago

Notice that = json_encode($x, JSON_FORCE_OBJECT); ?> doesn't guarantee that $json is actually an object encoded with JSON syntax. It *only* guarantees that the output doesn't start with "[".
For example:
json_encode("foo", JSON_FORCE_OBJECT); # "foo"
json_encode(42, JSON_FORCE_OBJECT); # 42
json_encode(false, JSON_FORCE_OBJECT); # false
json_encode("false", JSON_FORCE_OBJECT); # "false"
json_encode(10/3, JSON_FORCE_OBJECT); # 3.3333333333333335
?>

programming php JSON trong PHP JSON encode PHP Json_decode

Hướng dẫn object to json php

Chuyển array thành json string

Array thành json string

Chuyển ngược lại json string thành array

Chuyển Object thành json string

Encode

Decode

Description

Parameters

Return Values

Changelog

Examples

Notes

See Also

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