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
$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();
}
}
