PHP中urlencode和rawurlencode的区别

昨天看UCHome源码的时候，发现有些地方用urlencode，有些地方用rawurlencode。由于对这两个方法的差异不是很清楚，特意写了一段代码来测试。

请将下面的代码保存到一个PHP文件中：

<?php  
test_encode('http://www.baidu.com?a=search&k=eclipse');  
test_encode(':/?= &#');  
test_encode('中文');  
function test_encode($s)  
{  
  echo "<b>urlencode('$s')</b> = [<b>";  
  var_dump(urlencode($s));    
  echo "</b>]<br/>";  
  echo "<b>rawurlencode('$s')</b> = [<b>";  
  var_dump(rawurlencode($s));    
  echo "</b>]<br/>";  
}       

urlencode('http://www.baidu.com?a=search&k=eclipse') = [string(53) "http%3A%2F%2Fwww.baidu.com%3Fa%3Dsearch%26k%3Declipse" ]  
rawurlencode('http://www.baidu.com?a=search&k=eclipse') = [string(53) "http%3A%2F%2Fwww.baidu.com%3Fa%3Dsearch%26k%3Declipse" ]  
urlencode(':/?= &#') = [string(19) "%3A%2F%3F%3D+%26%23" ]  
rawurlencode(':/?= &#') = [string(21) "%3A%2F%3F%3D%20%26%23" ]  
urlencode('中文') = [string(18) "%E4%B8%AD%E6%96%87" ]  
rawurlencode('中文') = [string(18) "%E4%B8%AD%E6%96%87" ]