Object 在 class 级别创建

Question

public class DoSomething { private static final Logger logger = LoggerFactory.getLogger(DoSomething.class);

private final AtomicBoolean Flag = new AtomicBoolean(false);

LogMessage logMessage= new LogMessage(); // Creating an object to call a method in it

public static final String ERROR_MAP = "ERROR_MAP";
public static final String errorJsonString = System.getenv("RESTART_ERROR_MAP");

I tried to create an object of LogMessage. And use it inside a method of DoSomething class. Is this fine or should I move that line inside the method?

Answer 1

You haven't told us much about your LogMessage class. However, in general:

• you should try to declare variables as close as possible to where they're first used.
• you should try to instantiate class instances when you declare the class variable.
• you should try to restrict the visibility of a variable to only that area of the code wehre it's used.

If you're only using LogMessage inside a method... and if you're not going to re-use that instance across different method invocations... I'd suggest you declare and initialize it inside the method.