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  • 位置: php7教程 -> php7绑定的扩展库

    json函数(JavaScript对象符号)

    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,0will 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_UTF16(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_decode() 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.
    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]
    ?>
    
    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 => 1JSON_HEX_AMP => 2JSON_HEX_APOS => 4JSON_HEX_QUOT => 8JSON_FORCE_OBJECT => 16JSON_NUMERIC_CHECK => 32JSON_UNESCAPED_SLASHES => 64JSON_PRETTY_PRINT => 128JSON_UNESCAPED_UNICODE => 256JSON_ERROR_DEPTH => 1JSON_ERROR_STATE_MISMATCH => 2JSON_ERROR_CTRL_CHAR => 3JSON_ERROR_SYNTAX => 4JSON_ERROR_UTF8 => 5JSON_OBJECT_AS_ARRAY => 1JSON_BIGINT_AS_STRING => 2
    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.
    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
    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
    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
    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"}