APP接口写法

输出json：
<?php
header("Content-type: application/json");
$arr = array('str_key' => 'str_val', 'timestamp' => 1380000000);
echo json_encode($arr);
?>

输出xml:
<?php  
header("Content-type: text/xml");  
echo "<?xml version=\"1.0\" encoding=\"utf-8\"?>";  
echo "<data><demo>value</demo></data>";  
?>