异常是程序执行过程中出现的问题。在程序执行过程中，发生异常时，该语句后面的代码将不会被执行，PHP 将尝试查找第一个匹配的 catch 块。如果未捕获异常，则会发出 PHP 致命错误，并显示“未捕获异常”。
语法
try {
print "this is our try block";
throw new Exception();
}catch (Exception $e) {
print "something went wrong, caught yah! n";
}finally {
print "this part is always executed";
}Example
的中文翻译为：示例
<?php
function printdata($data) {
try {
//If var is six then only if will be executed
if($data == 6) {
// If var is zero then only exception is thrown
throw new Exception('Number is six.');
echo "</p><p> After throw (It will never be executed)";
}
}
// When Exception has been thrown by try block
catch(Exception $e){
echo "</p><p> Exception Caught", $e->getMessage();
}
//this block code will always executed.
finally{
echo "</p><p> Final block will be always executed";
}
}
// Exception will not be rised here
printdata(0);
// Exception will be rised
printdata(6);
?>输出
Final block will be always executed Exception CaughtNumber is six. Final block will be always executed
注意
要处理异常，程序代码必须位于 try 块内。每次尝试必须至少有一个相应的 catch 块。多个catch块可用于捕获不同类别的异常。
