json_encode在ajax应用的开发里是必不可少的一个函数，但是json_encode的使用条件是比较苛刻的，需要在php 5.2.0以上并且需要PECL json在1.2.0以上才可以使用。
其实json_encode的替代方法在网上有很多，这里提供一个在php在线手册里看到的一个简单的函数，已经通过测试。
function jsonEncode($var) {
if (function_exists('json_encode')) {
return json_encode($var);
} else {
switch (gettype($var)) {
case 'boolean':
return $var ? 'true' : 'false'; // Lowercase necessary!
case 'integer':
case 'double':
return $var;
case 'resource':
case 'string':
return '"'. str_replace(array("\r", "\n", "<", ">", "&"),
array('\r', '\n', '\x3c', '\x3e', '\x26'),
addslashes($var)) .'"';
case 'array':
// Arrays in JSON can't be associative. If the array is empty or if it
// has sequential whole number keys starting with 0, it's not associative
// so we can go ahead and convert it as an array.
if (empty ($var) || array_keys($var) === range(0, sizeof($var) - 1)) {
$output = array();
foreach ($var as $v) {
$output[] = jsonEncode($v);
}
return '[ '. implode(', ', $output) .' ]';
}
// Otherwise, fall through to convert the array as an object.
case 'object':
$output = array();
foreach ($var as $k => $v) {
$output[] = jsonEncode(strval($k)) .': '. jsonEncode($v);
}
return '{ '. implode(', ', $output) .' }';
default:
return 'null';
}
}
}
echo jsonEncode(array('first'=>'testing','second'=>'tangjili'));或者用下面：
<?php
function php_json_encode( $data ) {
if( is_array($data) || is_object($data) ) {
$islist = is_array($data) && ( empty($data) || array_keys($data) === range(0,count($data)-1) );
if( $islist ) $json = '[' . implode(',', array_map('php_json_encode', $data) ) . ']';
else {
$items = Array();
foreach( $data as $key => $value ) $items[] = php_json_encode("$key") . ':' . php_json_encode($value);
$json = '{' . implode(',', $items) . '}';
}
} elseif( is_string($data) ) {
$string = '"' . addcslashes($data, "\\\"\n\r\t/" . chr(8) . chr(12)) . '"';
$json = '';
$len = strlen($string);
for( $i = 0; $i < $len; $i++ ) {
$char = $string[$i];
$c1 = ord($char);
if( $c1 <128 ) { $json .= ($c1 > 31) ? $char : sprintf("\\u%04x", $c1); continue; }
$c2 = ord($string[++$i]);
if ( ($c1 & 32) === 0 ) { $json .= sprintf("\\u%04x", ($c1 - 192) * 64 + $c2 - 128); continue; }
$c3 = ord($string[++$i]);
if( ($c1 & 16) === 0 ) { $json .= sprintf("\\u%04x", (($c1 - 224) <<12) + (($c2 - 128) << 6) + ($c3 - 128)); continue; }
$c4 = ord($string[++$i]);
if( ($c1 & 8 ) === 0 ) {
$u = (($c1 & 15) << 2) + (($c2>>4) & 3) - 1;
$w1 = (54<<10) + ($u<<6) + (($c2 & 15) << 2) + (($c3>>4) & 3);
$w2 = (55<<10) + (($c3 & 15)<<6) + ($c4-128);
$json .= sprintf("\\u%04x\\u%04x", $w1, $w2);
}
}
}
else $json = strtolower(var_export( $data, true ));
return $json;
}
echo php_json_encode(array('first'=>'testing'));
如果想要现实中文可以结合下面的function
function arrayRecursive(&$array, $function, $apply_to_keys_also = false)
{
foreach ($array as $key => $value) {
if (is_array($value)) arrayRecursive($array[$key], $function, $apply_to_keys_also);
else $array[$key] = $function($value);
if ($apply_to_keys_also && is_string($key)) { $new_key = $function($key); if ($new_key != $key) { $array[$new_key] = $array[$key]; unset($array[$key]); } }
}
}
例子：
function JSON($array) {
arrayRecursive($array, 'urlencode', true);
$json = jsonEncode($array); // 或者 $json = php_json_encode($array);
return urldecode($json);
}
echo JSON(array('first'=>'testing','second'=>'中文'));
