php异常处理技术，顶级异常处理器，php异常处理

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<?<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>?>