我使用try-catch多年,但我从来没有学到如何和什么时候使用终于,因为我从来没有明白的点终于(我读坏书)?
我想问你最后在我的情况下的使用.
我的代码示例应该解释一切:
$s = ""; $c = MyClassForFileHandling::getInstance(); try { $s = $c->get_file_content($path); } catch FileNotFoundExeption { $c->create_file($path,"text for new file"); } finally { $s = $c->get_file_content($path); }
问题是:
这是正确的用法吗?
编辑:更精确的问题:
我最后会使用(以后的PHP版本或其他语言)来处理“创建一些如果不存在”操作?
最终总是执行,所以在这种情况下,这不是它的预期目的,因为正常的执行会再次打开文件.如果你这样做,你打算做的就是以同样(更清洁)的方式实现
原文链接:https://www.f2er.com/php/140074.html$s = ""; $c = MyClassForFileHandling::getInstance(); try { $s = $c->get_file_content($path); } catch(FileNotFoundExeption $e) { $c->create_file($path,"text for new file"); $s = $c->get_file_content($path); }
然后手册说:
For the benefit of someone anyone who hasn’t come across finally blocks before,the key difference between them and normal code following a try/catch block is that they will be executed even the try/catch block would return control to the calling function.
It might do this if:
- code if your try block contains an exception type that you don’t catch
- you throw another exception in your catch block
- your try or catch block calls return
那么最后在这种情况下会是有用的:
function my_get_file_content($path) { try { return $c->get_file_content($path); } catch(FileNotFoundExeption $e) { $c->create_file($path,"text for new file"); return $c->get_file_content($path); } finally { $c->close_file_handler(); } }