我需要在平面文件中存储多维数据关联数组，以便进行缓存。我可能偶尔会遇到需要将其转换为JSON以在我的web应用程序中使用，但绝大多数情况下，我将直接在PHP中使用数组。
在这个文本文件中将数组存储为JSON还是PHP序列化数组更有效?我查看了一下，似乎在最新版本的PHP(5.3)中，json_decode实际上比反序列化更快。
我目前倾向于将数组存储为JSON，因为我觉得如果有必要的话，它更容易被人阅读，它可以在PHP和JavaScript中使用，而且从我所读到的，它甚至可能更快地解码(虽然不确定编码)。
有人知道有什么陷阱吗?有人有好的基准来显示这两种方法的性能优势吗?
当前回答
我已经在一个相当复杂、嵌套简单、包含各种数据(字符串、NULL、整数)的多散列上对此进行了非常彻底的测试，序列化/反序列化最终比json_encode/json_decode快得多。
在我的测试中，json的唯一优势是它的“打包”大小更小。
这些都是在PHP 5.3.3下完成的，如果你想了解更多细节，请告诉我。
下面是测试结果，然后是生成它们的代码。我不能提供测试数据，因为它会泄露一些我不能公开的信息。
JSON encoded in 2.23700618744 seconds
PHP serialized in 1.3434419632 seconds
JSON decoded in 4.0405561924 seconds
PHP unserialized in 1.39393305779 seconds
serialized size : 14549
json_encode size : 11520
serialize() was roughly 66.51% faster than json_encode()
unserialize() was roughly 189.87% faster than json_decode()
json_encode() string was roughly 26.29% smaller than serialize()
// Time json encoding
$start = microtime( true );
for($i = 0; $i < 10000; $i++) {
json_encode( $test );
}
$jsonTime = microtime( true ) - $start;
echo "JSON encoded in $jsonTime seconds<br>";
// Time serialization
$start = microtime( true );
for($i = 0; $i < 10000; $i++) {
serialize( $test );
}
$serializeTime = microtime( true ) - $start;
echo "PHP serialized in $serializeTime seconds<br>";
// Time json decoding
$test2 = json_encode( $test );
$start = microtime( true );
for($i = 0; $i < 10000; $i++) {
json_decode( $test2 );
}
$jsonDecodeTime = microtime( true ) - $start;
echo "JSON decoded in $jsonDecodeTime seconds<br>";
// Time deserialization
$test2 = serialize( $test );
$start = microtime( true );
for($i = 0; $i < 10000; $i++) {
unserialize( $test2 );
}
$unserializeTime = microtime( true ) - $start;
echo "PHP unserialized in $unserializeTime seconds<br>";
$jsonSize = strlen(json_encode( $test ));
$phpSize = strlen(serialize( $test ));
echo "<p>serialized size : " . strlen(serialize( $test )) . "<br>";
echo "json_encode size : " . strlen(json_encode( $test )) . "<br></p>";
// Compare them
if ( $jsonTime < $serializeTime )
{
echo "json_encode() was roughly " . number_format( ($serializeTime / $jsonTime - 1 ) * 100, 2 ) . "% faster than serialize()";
}
else if ( $serializeTime < $jsonTime )
{
echo "serialize() was roughly " . number_format( ($jsonTime / $serializeTime - 1 ) * 100, 2 ) . "% faster than json_encode()";
} else {
echo 'Unpossible!';
}
echo '<BR>';
// Compare them
if ( $jsonDecodeTime < $unserializeTime )
{
echo "json_decode() was roughly " . number_format( ($unserializeTime / $jsonDecodeTime - 1 ) * 100, 2 ) . "% faster than unserialize()";
}
else if ( $unserializeTime < $jsonDecodeTime )
{
echo "unserialize() was roughly " . number_format( ($jsonDecodeTime / $unserializeTime - 1 ) * 100, 2 ) . "% faster than json_decode()";
} else {
echo 'Unpossible!';
}
echo '<BR>';
// Compare them
if ( $jsonSize < $phpSize )
{
echo "json_encode() string was roughly " . number_format( ($phpSize / $jsonSize - 1 ) * 100, 2 ) . "% smaller than serialize()";
}
else if ( $phpSize < $jsonSize )
{
echo "serialize() string was roughly " . number_format( ($jsonSize / $phpSize - 1 ) * 100, 2 ) . "% smaller than json_encode()";
} else {
echo 'Unpossible!';
}
其他回答
我对测试进行了扩展，以包括反序列化性能。这是我得到的数字。
Serialize
JSON encoded in 2.5738489627838 seconds
PHP serialized in 5.2861361503601 seconds
Serialize: json_encode() was roughly 105.38% faster than serialize()
Unserialize
JSON decode in 10.915472984314 seconds
PHP unserialized in 7.6223039627075 seconds
Unserialize: unserialize() was roughly 43.20% faster than json_decode()
因此json似乎编码更快，但解码较慢。因此，这可能取决于您的应用程序以及您希望最大限度地实现什么。
在你做出最终决定之前，请注意JSON格式对于关联数组是不安全的——json_decode()将它们作为对象返回:
$config = array(
'Frodo' => 'hobbit',
'Gimli' => 'dwarf',
'Gandalf' => 'wizard',
);
print_r($config);
print_r(json_decode(json_encode($config)));
输出是:
Array
(
[Frodo] => hobbit
[Gimli] => dwarf
[Gandalf] => wizard
)
stdClass Object
(
[Frodo] => hobbit
[Gimli] => dwarf
[Gandalf] => wizard
)
如果您想在不同的机器上或通过FTP备份数据和恢复数据，JSON更好。
例如，serialize如果你在Windows服务器上存储数据，通过FTP下载并将其恢复到Linux服务器上，由于字符重新编码，它不能再工作了，因为serialize存储字符串的长度，并且在Unicode > UTF-8转码中，一些1字节的字符可能会变成2字节长，使算法崩溃。
Y刚刚测试了serialized和json的encode和decode，加上它将把字符串存储的大小。
JSON encoded in 0.067085981369 seconds. Size (1277772)
PHP serialized in 0.12110209465 seconds. Size (1955548)
JSON decode in 0.22470498085 seconds
PHP serialized in 0.211947917938 seconds
json_encode() was roughly 80.52% faster than serialize()
unserialize() was roughly 6.02% faster than json_decode()
JSON string was roughly 53.04% smaller than Serialized string
我们可以得出结论，JSON编码更快，结果字符串更小，但unserialize解码字符串更快。
首先，我修改了脚本，做了更多的基准测试(也做了1000次而不是1次):
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
// Make a big, honkin test array
// You may need to adjust this depth to avoid memory limit errors
$testArray = fillArray(0, 5);
$totalJsonTime = 0;
$totalSerializeTime = 0;
$totalJsonWins = 0;
for ($i = 0; $i < 1000; $i++) {
// Time json encoding
$start = microtime(true);
$json = json_encode($testArray);
$jsonTime = microtime(true) - $start;
$totalJsonTime += $jsonTime;
// Time serialization
$start = microtime(true);
$serial = serialize($testArray);
$serializeTime = microtime(true) - $start;
$totalSerializeTime += $serializeTime;
if ($jsonTime < $serializeTime) {
$totalJsonWins++;
}
}
$totalSerializeWins = 1000 - $totalJsonWins;
// Compare them
if ($totalJsonTime < $totalSerializeTime) {
printf("json_encode() (wins: $totalJsonWins) was roughly %01.2f%% faster than serialize()\n", ($totalSerializeTime / $totalJsonTime - 1) * 100);
} else {
printf("serialize() (wins: $totalSerializeWins) was roughly %01.2f%% faster than json_encode()\n", ($totalJsonTime / $totalSerializeTime - 1) * 100);
}
$totalJsonTime = 0;
$totalJson2Time = 0;
$totalSerializeTime = 0;
$totalJsonWins = 0;
for ($i = 0; $i < 1000; $i++) {
// Time json decoding
$start = microtime(true);
$orig = json_decode($json, true);
$jsonTime = microtime(true) - $start;
$totalJsonTime += $jsonTime;
$start = microtime(true);
$origObj = json_decode($json);
$jsonTime2 = microtime(true) - $start;
$totalJson2Time += $jsonTime2;
// Time serialization
$start = microtime(true);
$unserial = unserialize($serial);
$serializeTime = microtime(true) - $start;
$totalSerializeTime += $serializeTime;
if ($jsonTime < $serializeTime) {
$totalJsonWins++;
}
}
$totalSerializeWins = 1000 - $totalJsonWins;
// Compare them
if ($totalJsonTime < $totalSerializeTime) {
printf("json_decode() was roughly %01.2f%% faster than unserialize()\n", ($totalSerializeTime / $totalJsonTime - 1) * 100);
} else {
printf("unserialize() (wins: $totalSerializeWins) was roughly %01.2f%% faster than json_decode()\n", ($totalJsonTime / $totalSerializeTime - 1) * 100);
}
// Compare them
if ($totalJson2Time < $totalSerializeTime) {
printf("json_decode() was roughly %01.2f%% faster than unserialize()\n", ($totalSerializeTime / $totalJson2Time - 1) * 100);
} else {
printf("unserialize() (wins: $totalSerializeWins) was roughly %01.2f%% faster than array json_decode()\n", ($totalJson2Time / $totalSerializeTime - 1) * 100);
}
function fillArray( $depth, $max ) {
static $seed;
if (is_null($seed)) {
$seed = array('a', 2, 'c', 4, 'e', 6, 'g', 8, 'i', 10);
}
if ($depth < $max) {
$node = array();
foreach ($seed as $key) {
$node[$key] = fillArray($depth + 1, $max);
}
return $node;
}
return 'empty';
}
我使用PHP 7的这个版本:
PHP 7.0.14 (cli)(已构建:2017年1月18日19:13:23)(NTS)版权所有(c) PHP Group Zend Engine v3.0.0，版权所有(c) 1998-2016 Zend技术 与Zend OPcache v7.0.14，版权(c) 1999-2016，由Zend Technologies
我的结果是:
Serialize()(胜:999)比json_encode()快大约10.98% Unserialize()(胜:987)大约比json_decode()快33.26% Unserialize()(胜:987)大约比array快48.35% json_decode ()
显然，序列化/反序列化是最快的方法，而json_encode/decode是最可移植的方法。
如果您考虑这样一个场景:您读/写序列化数据的次数是向非php系统发送数据或从非php系统接收数据的次数的10倍或更多，那么就时间而言，最好还是使用序列化/反序列化，并在序列化之前使用json_encode或json_decode。
