php对异常的处理与java一样，用到的是try{}catch(){}
定义顶级异常处理器用到的函数是 set_exception_handler("My_exception"); 这里的My_expection是开发者自定义的异常处理函数，既顶级异常处理器，只有当程序中没有函数来处理异常才有顶级异常处理器来处理异常，如果没有定义顶级异常处理器，则由系统默认的异常处理器来处理异常 举例说明：
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<?<span>php
</span><span>set_exception_handler</span>("My_expection"<span>);
</span><span>function</span><span> My_expection(){
</span><span>echo</span> "这里是顶级异常处理器"<span>;
}
</span><span>try</span><span>{
nohello(</span>"hello"<span>);
}</span><span>catch</span>(<span>Exception</span> <span>$e</span><span>){
</span><span>throw</span> <span>$e</span><span>;
}
</span><span>function</span> nohello(<span>$nohello</span><span>){
</span><span>if</span>(<span>$nohello</span> == "hello"<span>){
</span><span>throw</span> <span>new</span> <span>Exception</span>("不能输入hello"<span>);
}</span><span>else</span><span>{
</span><span>echo</span> "输入成功"<span>;
}
}
</span>?>
转载自：http://blog.sina.com.cn/s/blog_641d5693010121cr.html
