How should I replicate the functionality of C#'s 'using' statement in Java?
I'm converting some C# code to Java and it contains the using
statement. How should I replicate this functionality in Java? I was going to use a try
, catch
, 开发者_JS百科finally
block but I thought I'd check with you guys first.
That's correct. A C# using block is just syntactic sugar for that anyway. The closest Java equivalent to IDisposable is Closeable
.
There is a proposal (which is partially committed already), called Automatic Resource Management, for adding similar functionality to Java 7. It would use try-finally behind the scenes, and proposes creating a new Disposable interface (which would be a superinterface of Closeable).
The standard idiom for resource handling in Java is:
final Resource resource = acquire();
try {
use(resource);
} finally {
resource.dispose();
}
Common mistakes include trying to share the same try
statement with exception catching and following on from that making a mess with null
s and such.
The Execute Around Idiom can extract constructs like this, although the Java syntax is verbose.
executeWith(new Handler() { public void use(Resource resource) {
...
}});
Don't forget the null checking! That is to say
using(Reader r = new FileReader("c:\test")){
//some code here
}
should be translated to something like
Reader r = null;
try{
//some code here
}
finally{
if(r != null){
r.close()
}
}
And also most close() in java throw exceptions, so check DbUtils.closeQuietly if you want your code to be more c# like
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