mirror of
https://github.com/php/doc-zh.git
synced 2026-03-24 15:12:20 +01:00
416 lines
12 KiB
XML
416 lines
12 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
|
||
<!-- $Revision$ -->
|
||
<!-- EN-Revision: 9f2e30a00afda6d6b6a3e19b13956150c2eaf2c1 Maintainer: daijie Status: ready -->
|
||
<!-- CREDITS: mowangjuanzi, Luffy -->
|
||
<refentry xml:id="function.json-encode" xmlns="http://docbook.org/ns/docbook">
|
||
<refnamediv>
|
||
<refname>json_encode</refname>
|
||
<refpurpose>对变量进行 JSON 编码</refpurpose>
|
||
</refnamediv>
|
||
|
||
<refsect1 role="description">
|
||
&reftitle.description;
|
||
<methodsynopsis>
|
||
<type class="union"><type>string</type><type>false</type></type><methodname>json_encode</methodname>
|
||
<methodparam><type>mixed</type><parameter>value</parameter></methodparam>
|
||
<methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>0</initializer></methodparam>
|
||
<methodparam choice="opt"><type>int</type><parameter>depth</parameter><initializer>512</initializer></methodparam>
|
||
</methodsynopsis>
|
||
<para>
|
||
返回字符串，包含了 <parameter>value</parameter> 值 JSON 形式的表示。如果参数是 &array; 或 &object;，则会递归序列化。
|
||
</para>
|
||
<para>
|
||
如果要序列化的值是对象，则默认仅包含公开可见的属性，或者类可以实现 <interfacename>JsonSerializable</interfacename>
|
||
控制其值如何序列化为 <acronym>JSON</acronym>。
|
||
</para>
|
||
<para>
|
||
编码受传入的 <parameter>flags</parameter> 参数影响，此外浮点值的编码依赖于 <link linkend="ini.serialize-precision">serialize_precision</link>。
|
||
</para>
|
||
</refsect1>
|
||
|
||
<refsect1 role="parameters">
|
||
&reftitle.parameters;
|
||
<para>
|
||
<variablelist>
|
||
<varlistentry>
|
||
<term><parameter>value</parameter></term>
|
||
<listitem>
|
||
<para>
|
||
待编码的 <parameter>value</parameter> ，除了 &resource;
|
||
类型之外，可以为任何数据类型。
|
||
</para>
|
||
<para>
|
||
所有字符串数据的编码必须是 UTF-8。
|
||
</para>
|
||
&json.implementation.superset;
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term><parameter>flags</parameter></term>
|
||
<listitem>
|
||
<para>
|
||
由以下常量组成的二进制掩码：
|
||
<constant>JSON_FORCE_OBJECT</constant>、
|
||
<constant>JSON_HEX_QUOT</constant>、
|
||
<constant>JSON_HEX_TAG</constant>、
|
||
<constant>JSON_HEX_AMP</constant>、
|
||
<constant>JSON_HEX_APOS</constant>、
|
||
<constant>JSON_INVALID_UTF8_IGNORE</constant>、
|
||
<constant>JSON_INVALID_UTF8_SUBSTITUTE</constant>、
|
||
<constant>JSON_NUMERIC_CHECK</constant>、
|
||
<constant>JSON_PARTIAL_OUTPUT_ON_ERROR</constant>、
|
||
<constant>JSON_PRESERVE_ZERO_FRACTION</constant>、
|
||
<constant>JSON_PRETTY_PRINT</constant>、
|
||
<constant>JSON_UNESCAPED_LINE_TERMINATORS</constant>、
|
||
<constant>JSON_UNESCAPED_SLASHES</constant>、
|
||
<constant>JSON_UNESCAPED_UNICODE</constant>、
|
||
<constant>JSON_THROW_ON_ERROR</constant>。
|
||
关于 JSON 常量详情参考
|
||
<link linkend="json.constants">JSON 常量</link>页面。
|
||
</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
<varlistentry>
|
||
<term><parameter>depth</parameter></term>
|
||
<listitem>
|
||
<para>
|
||
设置最大深度。 必须大于0。
|
||
</para>
|
||
</listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</para>
|
||
</refsect1>
|
||
|
||
<refsect1 role="returnvalues">
|
||
&reftitle.returnvalues;
|
||
<para>
|
||
成功则返回 JSON 编码的 &string; &return.falseforfailure; 。
|
||
</para>
|
||
</refsect1>
|
||
|
||
|
||
<refsect1 role="changelog">
|
||
&reftitle.changelog;
|
||
<para>
|
||
<informaltable>
|
||
<tgroup cols="2">
|
||
<thead>
|
||
<row>
|
||
<entry>&Version;</entry>
|
||
<entry>&Description;</entry>
|
||
</row>
|
||
</thead>
|
||
<tbody>
|
||
<row>
|
||
<entry>7.3.0</entry>
|
||
<entry>
|
||
<parameter>flags</parameter> 参数新增
|
||
<constant>JSON_THROW_ON_ERROR</constant>
|
||
常量。
|
||
</entry>
|
||
</row>
|
||
<row>
|
||
<entry>7.2.0</entry>
|
||
<entry>
|
||
<parameter>flags</parameter> 参数新增
|
||
<constant>JSON_INVALID_UTF8_IGNORE</constant> 和
|
||
<constant>JSON_INVALID_UTF8_SUBSTITUTE</constant>
|
||
常量。
|
||
</entry>
|
||
</row>
|
||
<row>
|
||
<entry>7.1.0</entry>
|
||
<entry>
|
||
<parameter>flags</parameter> 参数新增
|
||
<constant>JSON_UNESCAPED_LINE_TERMINATORS</constant>
|
||
常量。
|
||
</entry>
|
||
</row>
|
||
<row>
|
||
<entry>7.1.0</entry>
|
||
<entry>
|
||
对 <type>float</type> 值进行编码时，使用
|
||
<link linkend="ini.serialize-precision">serialize_precision</link> 代替
|
||
<link linkend="ini.precision">precision</link>。
|
||
</entry>
|
||
</row>
|
||
</tbody>
|
||
</tgroup>
|
||
</informaltable>
|
||
</para>
|
||
</refsect1>
|
||
<refsect1 role="examples">
|
||
&reftitle.examples;
|
||
<para>
|
||
<example>
|
||
<title><function>json_encode</function> 例子</title>
|
||
<programlisting role="php">
|
||
<![CDATA[
|
||
<?php
|
||
$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
|
||
|
||
echo json_encode($arr);
|
||
?>
|
||
]]>
|
||
</programlisting>
|
||
&example.outputs;
|
||
<screen>
|
||
<![CDATA[
|
||
{"a":1,"b":2,"c":3,"d":4,"e":5}
|
||
]]>
|
||
</screen>
|
||
</example>
|
||
|
||
<example>
|
||
<title> <function>json_encode</function> 函数中 flags 参数的用法</title>
|
||
<programlisting role="php">
|
||
<![CDATA[
|
||
<?php
|
||
$a = array('<foo>',"'bar'",'"baz"','&blong&', "\xc3\xa9");
|
||
|
||
echo "Normal: ", json_encode($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";
|
||
?>
|
||
]]>
|
||
</programlisting>
|
||
&example.outputs;
|
||
<screen>
|
||
<![CDATA[
|
||
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
|
||
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
|
||
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
|
||
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
|
||
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
|
||
Unicode: ["<foo>","'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"}
|
||
]]>
|
||
</screen>
|
||
</example>
|
||
<example>
|
||
<title>选项 JSON_NUMERIC_CHECK 例子</title>
|
||
<programlisting role="php">
|
||
<![CDATA[
|
||
<?php
|
||
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)
|
||
);
|
||
?>
|
||
]]>
|
||
</programlisting>
|
||
&example.outputs.similar;
|
||
<screen>
|
||
<![CDATA[
|
||
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"]"
|
||
]]>
|
||
</screen>
|
||
</example>
|
||
<example>
|
||
<title>连续与非连续数组示例</title>
|
||
<programlisting role="php">
|
||
<![CDATA[
|
||
<?php
|
||
echo "连续数组".PHP_EOL;
|
||
$sequential = array("foo", "bar", "baz", "blong");
|
||
var_dump(
|
||
$sequential,
|
||
json_encode($sequential)
|
||
);
|
||
|
||
echo PHP_EOL."非连续数组".PHP_EOL;
|
||
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
|
||
var_dump(
|
||
$nonsequential,
|
||
json_encode($nonsequential)
|
||
);
|
||
|
||
echo PHP_EOL."删除一个连续数组值的方式产生的非连续数组".PHP_EOL;
|
||
unset($sequential[1]);
|
||
var_dump(
|
||
$sequential,
|
||
json_encode($sequential)
|
||
);
|
||
?>
|
||
]]>
|
||
</programlisting>
|
||
&example.outputs;
|
||
<screen>
|
||
<![CDATA[
|
||
连续数组
|
||
array(4) {
|
||
[0]=>
|
||
string(3) "foo"
|
||
[1]=>
|
||
string(3) "bar"
|
||
[2]=>
|
||
string(3) "baz"
|
||
[3]=>
|
||
string(5) "blong"
|
||
}
|
||
string(27) "["foo","bar","baz","blong"]"
|
||
|
||
非连续数组
|
||
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"}"
|
||
|
||
删除一个连续数组值的方式产生的非连续数组
|
||
array(3) {
|
||
[0]=>
|
||
string(3) "foo"
|
||
[2]=>
|
||
string(3) "baz"
|
||
[3]=>
|
||
string(5) "blong"
|
||
}
|
||
string(33) "{"0":"foo","2":"baz","3":"blong"}"
|
||
]]>
|
||
</screen>
|
||
</example>
|
||
<example>
|
||
<title><constant>选项 JSON_PRESERVE_ZERO_FRACTION</constant> 的例子</title>
|
||
<programlisting role="php">
|
||
<![CDATA[
|
||
<?php
|
||
var_dump(json_encode(12.0, JSON_PRESERVE_ZERO_FRACTION));
|
||
var_dump(json_encode(12.0));
|
||
?>
|
||
]]>
|
||
</programlisting>
|
||
&example.outputs;
|
||
<screen>
|
||
<![CDATA[
|
||
string(4) "12.0"
|
||
string(2) "12"
|
||
]]>
|
||
</screen>
|
||
</example>
|
||
</para>
|
||
</refsect1>
|
||
|
||
|
||
<refsect1 role="notes">
|
||
&reftitle.notes;
|
||
<note>
|
||
<para>
|
||
如果执行失败，可以通过 <function>json_last_error</function> 函数来获取详细错误信息。
|
||
</para>
|
||
</note>
|
||
<note>
|
||
<para>
|
||
如果要编码的数组的键不是从0开始的数字，所有的键将会被当作字符串，并明确声明为 key-value 对。
|
||
</para>
|
||
</note>
|
||
|
||
<note>
|
||
<para>
|
||
参考 JSON 解析器，如果指定简单的 <type>string</type>、<type>integer</type>、<type>float</type> 或
|
||
<type>boolean</type> 作为输入 <parameter>value</parameter>，<function>json_encode</function>
|
||
将生成简单的值的 JSON（既不是对象又不是数组）。虽然大多数解码器会接受这些值作为有效的
|
||
JSON，但有些可能不会，因为在这一点上规范是模棱两可的。
|
||
</para>
|
||
<para>
|
||
总而言之，应该测试下 JSON decoder 能否处理 <function>json_encode</function> 生成的数据。
|
||
</para>
|
||
</note>
|
||
</refsect1>
|
||
|
||
<refsect1 role="seealso">
|
||
&reftitle.seealso;
|
||
<para>
|
||
<simplelist>
|
||
<member><interfacename>JsonSerializable</interfacename></member>
|
||
<member><function>json_decode</function></member>
|
||
<member><function>json_last_error</function></member>
|
||
<member><function>json_last_error_msg</function></member>
|
||
<member><function>serialize</function></member>
|
||
</simplelist>
|
||
</para>
|
||
</refsect1>
|
||
</refentry>
|
||
<!-- Keep this comment at the end of the file
|
||
Local variables:
|
||
mode: sgml
|
||
sgml-omittag:t
|
||
sgml-shorttag:t
|
||
sgml-minimize-attributes:nil
|
||
sgml-always-quote-attributes:t
|
||
sgml-indent-step:1
|
||
sgml-indent-data:t
|
||
indent-tabs-mode:nil
|
||
sgml-parent-document:nil
|
||
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
|
||
sgml-exposed-tags:nil
|
||
sgml-local-catalogs:nil
|
||
sgml-local-ecat-files:nil
|
||
End:
|
||
vim600: syn=xml fen fdm=syntax fdl=2 si
|
||
vim: et tw=78 syn=sgml
|
||
vi: ts=1 sw=1
|
||
-->
|