英文:
Equivalent of java finalize method
问题
在Go语言中是否有类似Java中的finalize方法？如果我有一个类似下面的结构体类型：
type Foo struct {
f *os.File
....
}
func (p *Foo) finalize() {
p.f.close( )
}
我该如何确保当对象被垃圾回收时，文件会被关闭？
英文:
Is there any method like java finalize in Go? If I've a type struct like
type Foo struct {
f *os.File
....
}
func (p *Foo) finalize() {
p.f.close( )
}
How can I make sure that when Object is garbage collected, the file is closed?
答案1
得分: 16
你在Java中也不会这样做。在Java中正确的做法是在打开的地方附近有一个finally块来关闭它。
在Go中，你可以使用defer函数来进行清理，类似的模式。例如，如果你在Java中这样做：
try {
open();
// 做一些操作
} finally {
close();
}
在Go中，你可以这样做：
open();
defer close();
// 做一些操作
英文:
You wouldn't do that in java, either. The correct thing to do in java is to have a finally block that closes it somewhere near where you opened up.
You'd use a similar pattern in go with a defer function to do the cleanup. For example, if you did this (java):
try {
open();
// do stuff
} finally {
close();
}
In go, you'd do this:
open();
defer close();
// do stuff
答案2
得分: 7
runtime.SetFinalizer据我所知。但这被认为是一件不好的事情，并不能保证在程序退出之前运行。
编辑：如下所述，当前的os包已经在文件上调用了runtime.SetFinalizer。然而，不应该依赖SetFinalizer。举个例子，我有一个类似文件服务器的应用程序，在那里我忘记关闭打开的文件。在垃圾回收器将它们拾起并调用它们的终结器之前，该进程通常会打开大约300个文件。
英文:
runtime.SetFinalizer iirc. But its considered a bad thing and isn't guaranteed to run before program exit
EDIT: As mentioned below, the current os package already calls runtime.SetFinalizer on files. However, SetFinalizer shouldn't be relied upon. As an example of why, I had a file-server-like application where I forgot to close open file. The process would usually get to about 300 open files before the GC picked them up and called their finalizer.
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