PHP中用SimpleXMLElement解析xml

<?php
$content = <<<XML
<?xml version="1.0" encoding="UTF-8"?>
<test>
 <global_setting>
  <ping_protocol>HTTP</ping_protocol>
  <ping_port>80</ping_port>
  <ping_path>/index.html</ping_path>
  <response_timeout>5000</response_timeout>
  <health_check_interval>3000</health_check_interval>
  <unhealthy_threshold>2</unhealthy_threshold>
  <healthy_threshold>3</healthy_threshold>
 </global_setting>
 <instances>
  <instance ip="192.168.234.121"/>
  <instance ip="192.168.234.28"/>
 </instances>
</test>
XML;

$test = new SimpleXMLElement($content);

//获得ping_protocol的值
$ping_protocol = $test->global_setting->ping_protocol;
echo "ping_protocol : $ping_protocol \n";

//打印出所有instance的IP
foreach ( $test->instances->instance as $instance) {
 echo "IP: {$instance['ip']} \n" ;
}