预定义常量

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)
没有错误发生。自 PHP 5.3.0 起生效。
JSON_ERROR_DEPTH (integer)
到达了最大堆栈深度。自 PHP 5.3.0 起生效。
JSON_ERROR_STATE_MISMATCH (integer)
出现了下溢(underflow)或者模式不匹配。自 PHP 5.3.0 起生效。
JSON_ERROR_CTRL_CHAR (integer)
控制字符错误,可能是编码不对。自 PHP 5.3.0 起生效。
JSON_ERROR_SYNTAX (integer)
语法错误。 自 PHP 5.3.0 起生效。
JSON_ERROR_UTF8 (integer)
异常的 UTF-8 字符,也许是因为不正确的编码。 自 PHP 5.3.3 起生效。
JSON_ERROR_RECURSION (integer)
The object or array passed to json_encode() include recursive references and cannot be encoded. If the 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)
The value passed to json_encode() includes either 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)
A value of an unsupported type was given to json_encode(), such as a resource. If the 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)
A key starting with \u0000 character was in the string passed to json_decode() when decoding a JSON object into a PHP object. Available since PHP 7.0.0.
JSON_ERROR_INVALID_PROPERTY_NAME (integer)
Single unpaired UTF-16 surrogate in unicode escape contained in the JSON string passed to json_encode(). Available since PHP 7.0.0.

下面的常量可以和 json_encode() 的 form 选项结合使用。

JSON_BIGINT_AS_STRING (integer)
将大数字编码成原始字符原来的值。 自 PHP 5.4.0 起生效。
JSON_OBJECT_AS_ARRAY (integer)
Decodes JSON objects as PHP array. This option can be added automatically by calling json_decode() with the second parameter equal to 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)
所有的 < 和 > 转换成 \u003C 和 \u003E。 自 PHP 5.3.0 起生效。
JSON_HEX_AMP (integer)
所有的 & 转换成 \u0026。 自 PHP 5.3.0 起生效。
JSON_HEX_APOS (integer)
所有的 ' 转换成 \u0027。 自 PHP 5.3.0 起生效。
JSON_HEX_QUOT (integer)
所有的 " 转换成 \u0022。 自 PHP 5.3.0 起生效。
JSON_FORCE_OBJECT (integer)
使一个非关联数组输出一个类(Object)而非数组。 在数组为空而接受者需要一个类(Object)的时候尤其有用。 自 PHP 5.3.0 起生效。
JSON_NUMERIC_CHECK (integer)
将所有数字字符串编码成数字(numbers)。 自 PHP 5.3.3 起生效。
JSON_PRETTY_PRINT (integer)
用空白字符格式化返回的数据。 自 PHP 5.4.0 起生效。
JSON_UNESCAPED_SLASHES (integer)
不要编码 /。 自 PHP 5.4.0 起生效。
JSON_UNESCAPED_UNICODE (integer)
以字面编码多字节 Unicode 字符(默认是编码成 \uXXXX)。 自 PHP 5.4.0 起生效。
JSON_PARTIAL_OUTPUT_ON_ERROR (integer)
Substitute some unencodable values instead of failing. Available since PHP 5.5.0.
JSON_PRESERVE_ZERO_FRACTION (integer)
Ensures that float values are always encoded as a float value. Available since PHP 5.6.6.
JSON_UNESCAPED_LINE_TERMINATORS (integer)
The line terminators are kept unescaped when 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.
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User Contributed Notes 5 notes

up
40
Yzmir Ramirez
2 years ago
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
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9
majid4466 at gmail dot com
8 months ago
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);
$good  = json_encode($arrayJSON_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]
?>
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0
JuanP
1 year ago
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
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-8
on5wis at mac dot com
1 year ago
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
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-19
Anonymous
1 year ago
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
$ar
= array("word" => "धाडस");
echo
json_encode($ar);
?>

Output of program is :

{"word":"\u0927\u093e\u0921\u0938"}

This is not expected output because what I need is output as

{"word":"धाडस"}

So I used following code:

<?php
$ar
= array("word" => "धाडस");
echo
json_encode($ar, JSON_UNESCAPED_UNICODE);
?>

And I got the required output as :

{"word":"धाडस"}
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