下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
以下常量表示了 json_last_error() 所返回的错误类型。
JSON_ERROR_NONE
(integer)
JSON_ERROR_DEPTH
(integer)
JSON_ERROR_STATE_MISMATCH
(integer)
JSON_ERROR_CTRL_CHAR
(integer)
JSON_ERROR_SYNTAX
(integer)
JSON_ERROR_UTF8
(integer)
JSON_ERROR_RECURSION
(integer)
JSON_PARTIAL_OUTPUT_ON_ERROR option was
given, NULL will be encoded in the place of the recursive reference.
Available since PHP 5.5.0.
JSON_ERROR_INF_OR_NAN
(integer)
NAN
or INF.
If the JSON_PARTIAL_OUTPUT_ON_ERROR option was
given, 0 will be encoded in the place of these
special numbers.
Available since PHP 5.5.0.
JSON_ERROR_UNSUPPORTED_TYPE
(integer)
JSON_PARTIAL_OUTPUT_ON_ERROR option was
given, NULL will be encoded in the place of the unsupported value.
Available since PHP 5.5.0.
JSON_ERROR_INVALID_PROPERTY_NAME
(integer)
JSON_ERROR_UTF16
(integer)
下面的常量可以和 json_decode() 的 form 选项结合使用。
JSON_BIGINT_AS_STRING
(integer)
JSON_OBJECT_AS_ARRAY
(integer)
TRUE.
Available since PHP 5.4.0.
下面的常量可以和 json_encode() 的 form 选项结合使用。
JSON_HEX_TAG
(integer)
JSON_HEX_AMP
(integer)
JSON_HEX_APOS
(integer)
JSON_HEX_QUOT
(integer)
JSON_FORCE_OBJECT
(integer)
JSON_NUMERIC_CHECK
(integer)
JSON_PRETTY_PRINT
(integer)
JSON_UNESCAPED_SLASHES
(integer)
JSON_UNESCAPED_UNICODE
(integer)
JSON_PARTIAL_OUTPUT_ON_ERROR
(integer)
JSON_PRESERVE_ZERO_FRACTION
(integer)
JSON_UNESCAPED_LINE_TERMINATORS
(integer)
JSON_UNESCAPED_UNICODE is supplied. It uses the same
behaviour as it was before PHP 7.1 without this constant.
Available since PHP 7.1.0.
flags JSON_NUMERIC_CHECK and JSON_PRESERVE_ZERO_FRACTION are broken in php 7+ — json_encode((float)8.8) returns "8.8000000000000007", and json_encode((float)8.8, JSON_NUMERIC_CHECK) and json_encode((float)8.8, JSON_PRESERVE_ZERO_FRACTION) return "8.8000000000000007" too.
the only way to fix this is setting "serialize_precision = -1" in php.ini
In a multi-level array, JSON_FORCE_OBJECT will encode ALL nested numeric arrays as objects.
If your concern was ONLY the first-level array (e.g., to make it suitable as a MySQL JSON column), you could just cast your first-level array to object, e.g.:
<?php
$json = json_encode( (object) $array, JSON_PRESERVE_ZERO_FRACTION+JSON_UNESCAPED_UNICODE );
?>
Or, if you have large arrays and are concerned about the overhead of object casting, you could append a "null" value beyond the size of the array, which will force the array to become associative:
<?php
$beyond = count( $array ) + 1;
if ( !array_key_exists( $beyond, $array) )
$array[ $beyond ] = NULL;
$json = json_encode( $array, JSON_PRESERVE_ZERO_FRACTION+JSON_UNESCAPED_UNICODE );
?>
Of course, your later code has to treat an element with a "NULL" value the same as "!isset()", if it iterates the array.
To get a really clean json string use these three constants like so:
<?php
$array = ['?, 'http://example.com/some/cool/page', '337'];
$bad = json_encode($array);
$good = json_encode($array, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES | JSON_NUMERIC_CHECK);
// $bad would be ["\u20ac","http:\/\/example.com\/some\/cool\/page","337"]
// $good would be ["?,"http://example.com/some/cool/page",337]
?>
Updated format values list:
JSON_HEX_TAG => 1
JSON_HEX_AMP => 2
JSON_HEX_APOS => 4
JSON_HEX_QUOT => 8
JSON_FORCE_OBJECT => 16
JSON_NUMERIC_CHECK => 32
JSON_UNESCAPED_SLASHES => 64
JSON_PRETTY_PRINT => 128
JSON_UNESCAPED_UNICODE => 256
JSON_PARTIAL_OUTPUT_ON_ERROR => 512
JSON_PRESERVE_ZERO_FRACTION => 1024
I am working with "Marathi Language Data" and I found that when I encoded Marathi data to json using json_encode it returned me unicode values of each character like below:
Program :
<?php
$ar = array("word" => "????");
echo json_encode($ar);
?>
Output of program is :
{"word":"\u0927\u093e\u0921\u0938"}
This is not expected output because what I need is output as
{"word":"????"}
So I used following code:
<?php
$ar = array("word" => "????");
echo json_encode($ar, JSON_UNESCAPED_UNICODE);
?>
And I got the required output as :
{"word":"????"}
since json_encode expects a UTF-8 string there is no need to encode the ?symbol.
I suggest you try to echo : json_encode('?);
It gives: "\u20ac"
I'm running PHP 5.6.5 on the CLI, on MacOS X 10.10
If you curious of the numeric values of the constants, as of JSON 1.2.1, the constants have the following values (not that you should use the numbers directly):
JSON_HEX_TAG => 1
JSON_HEX_AMP => 2
JSON_HEX_APOS => 4
JSON_HEX_QUOT => 8
JSON_FORCE_OBJECT => 16
JSON_NUMERIC_CHECK => 32
JSON_UNESCAPED_SLASHES => 64
JSON_PRETTY_PRINT => 128
JSON_UNESCAPED_UNICODE => 256
JSON_ERROR_DEPTH => 1
JSON_ERROR_STATE_MISMATCH => 2
JSON_ERROR_CTRL_CHAR => 3
JSON_ERROR_SYNTAX => 4
JSON_ERROR_UTF8 => 5
JSON_OBJECT_AS_ARRAY => 1
JSON_BIGINT_AS_STRING => 2