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
JSON比PHP的序列化格式更简单、更快，除非:
你正在存储深度嵌套数组: json_decode(): "如果JSON编码的数据大于127个元素，此函数将返回false。" 您存储的对象需要被反序列化为正确的类 您正在与不支持json_decode的旧PHP版本进行交互
其他回答
THX -用于此基准代码:
我的结果对阵列我使用的配置是休耕: JSON编码在0.0031511783599854秒 PHP在0.0037961006164551秒内序列化 Json_encode()比serialize()快20.47% JSON编码在0.0070841312408447秒 PHP在0.0035839080810547秒内序列化 Unserialize()比json_encode()快97.66%
用你自己的数据进行测试。
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。
看看这里的结果(很抱歉把PHP代码放在JS代码框中):
http://jsfiddle.net/newms87/h3b0a0ha/embedded/result/
结果:serialize()和unserialize()在PHP 5.4中对于不同大小的数组都要快得多。
我在真实世界的数据上做了一个测试脚本，比较json_encode vs serialize和json_decode vs unserialize。测试是在一个生产中的电子商务网站的缓存系统上运行的。它只是获取缓存中已经存在的数据，并测试编码/解码(或序列化/反序列化)所有数据的时间，然后我将其放入一个易于查看的表中。
我在PHP 5.4共享托管服务器上运行了这个程序。
结果是非常结论性的，对于这些大到小的数据集，序列化和非序列化是明显的赢家。特别是对于我的用例，json_decode和unserialize对于缓存系统是最重要的。在这里，Unserialize几乎是一个无处不在的赢家。它的速度通常是json_decode的2到4倍(有时是6或7倍)。
有趣的是，@peter-bailey的结果有所不同。
下面是用于生成结果的PHP代码:
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
function _count_depth($array)
{
$count = 0;
$max_depth = 0;
foreach ($array as $a) {
if (is_array($a)) {
list($cnt, $depth) = _count_depth($a);
$count += $cnt;
$max_depth = max($max_depth, $depth);
} else {
$count++;
}
}
return array(
$count,
$max_depth + 1,
);
}
function run_test($file)
{
$memory = memory_get_usage();
$test_array = unserialize(file_get_contents($file));
$memory = round((memory_get_usage() - $memory) / 1024, 2);
if (empty($test_array) || !is_array($test_array)) {
return;
}
list($count, $depth) = _count_depth($test_array);
//JSON encode test
$start = microtime(true);
$json_encoded = json_encode($test_array);
$json_encode_time = microtime(true) - $start;
//JSON decode test
$start = microtime(true);
json_decode($json_encoded);
$json_decode_time = microtime(true) - $start;
//serialize test
$start = microtime(true);
$serialized = serialize($test_array);
$serialize_time = microtime(true) - $start;
//unserialize test
$start = microtime(true);
unserialize($serialized);
$unserialize_time = microtime(true) - $start;
return array(
'Name' => basename($file),
'json_encode() Time (s)' => $json_encode_time,
'json_decode() Time (s)' => $json_decode_time,
'serialize() Time (s)' => $serialize_time,
'unserialize() Time (s)' => $unserialize_time,
'Elements' => $count,
'Memory (KB)' => $memory,
'Max Depth' => $depth,
'json_encode() Win' => ($json_encode_time > 0 && $json_encode_time < $serialize_time) ? number_format(($serialize_time / $json_encode_time - 1) * 100, 2) : '',
'serialize() Win' => ($serialize_time > 0 && $serialize_time < $json_encode_time) ? number_format(($json_encode_time / $serialize_time - 1) * 100, 2) : '',
'json_decode() Win' => ($json_decode_time > 0 && $json_decode_time < $serialize_time) ? number_format(($serialize_time / $json_decode_time - 1) * 100, 2) : '',
'unserialize() Win' => ($unserialize_time > 0 && $unserialize_time < $json_decode_time) ? number_format(($json_decode_time / $unserialize_time - 1) * 100, 2) : '',
);
}
$files = glob(dirname(__FILE__) . '/system/cache/*');
$data = array();
foreach ($files as $file) {
if (is_file($file)) {
$result = run_test($file);
if ($result) {
$data[] = $result;
}
}
}
uasort($data, function ($a, $b) {
return $a['Memory (KB)'] < $b['Memory (KB)'];
});
$fields = array_keys($data[0]);
?>
<table>
<thead>
<tr>
<?php foreach ($fields as $f) { ?>
<td style="text-align: center; border:1px solid black;padding: 4px 8px;font-weight:bold;font-size:1.1em"><?= $f; ?></td>
<?php } ?>
</tr>
</thead>
<tbody>
<?php foreach ($data as $d) { ?>
<tr>
<?php foreach ($d as $key => $value) { ?>
<?php $is_win = strpos($key, 'Win'); ?>
<?php $color = ($is_win && $value) ? 'color: green;font-weight:bold;' : ''; ?>
<td style="text-align: center; vertical-align: middle; padding: 3px 6px; border: 1px solid gray; <?= $color; ?>"><?= $value . (($is_win && $value) ? '%' : ''); ?></td>
<?php } ?>
</tr>
<?php } ?>
</tbody>
</table>
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 $node;
}
return 'empty';
}
我使用PHP 7的这个版本:
PHP 7.0.14 (cli)(已构建:2017年1月18日19:13:23)(NTS)版权所有(c) PHP Group Zend Engine v3.0.0，版权所有(c) 1998-2016 Zend技术 与Zend OPcache v7.0.14，版权(c) 1999-2016，由Zend Technologies
我的结果是:
Serialize()(胜:999)比json_encode()快大约10.98% Unserialize()(胜:987)大约比json_decode()快33.26% Unserialize()(胜:987)大约比array快48.35% json_decode ()
显然，序列化/反序列化是最快的方法，而json_encode/decode是最可移植的方法。
如果您考虑这样一个场景:您读/写序列化数据的次数是向非php系统发送数据或从非php系统接收数据的次数的10倍或更多，那么就时间而言，最好还是使用序列化/反序列化，并在序列化之前使用json_encode或json_decode。
这取决于你的优先级。
如果性能是你的绝对驾驶特点，那么无论如何要用最快的。在你做出选择之前，一定要充分了解它们之间的差异
Unlike serialize() you need to add extra parameter to keep UTF-8 characters untouched: json_encode($array, JSON_UNESCAPED_UNICODE) (otherwise it converts UTF-8 characters to Unicode escape sequences). JSON will have no memory of what the object's original class was (they are always restored as instances of stdClass). You can't leverage __sleep() and __wakeup() with JSON By default, only public properties are serialized with JSON. (in PHP>=5.4 you can implement JsonSerializable to change this behavior). JSON is more portable
可能还有其他一些不同之处，我现在想不出来。
一个简单的速度测试来比较两者
<?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);
// Time json encoding
$start = microtime(true);
json_encode($testArray);
$jsonTime = microtime(true) - $start;
echo "JSON encoded in $jsonTime seconds\n";
// Time serialization
$start = microtime(true);
serialize($testArray);
$serializeTime = microtime(true) - $start;
echo "PHP serialized in $serializeTime seconds\n";
// Compare them
if ($jsonTime < $serializeTime) {
printf("json_encode() was roughly %01.2f%% faster than serialize()\n", ($serializeTime / $jsonTime - 1) * 100);
}
else if ($serializeTime < $jsonTime ) {
printf("serialize() was roughly %01.2f%% faster than json_encode()\n", ($jsonTime / $serializeTime - 1) * 100);
} else {
echo "Impossible!\n";
}
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';
}
