问题
I am extending a very simple Java interface from an imported library. The interface is so simple that the only methods it declares are getters and setters for a list of properties.
My application is written in Groovy, so I'd like to implement this Java interface with a Groovy class.
I was under the impression that Groovy created getters and setters by default for any of its classes' properties - can I use these default getters and setters to satisfy the Java interface's requirements?
Library's Java interface:
public interface Animal { // java interface
public String getName();
public void setName(String name);
public Integer getAge();
public void setAge(Integer age);
}
I hoped I'd be able to implement it like this with Groovy (but my compiler is complaining about missing setters):
public class Cat implements Animal { // Groovy class
public String name;
public Integer age;
}
回答1:
You can do that with groovy properties, but take into account the difference between fields and properties:
A field is a member of a class or a trait which:
- a mandatory access modifier (public, protected, or private)
- one or more optional modifiers (static, final, synchronized)
- an optional type
- a mandatory name
[...]
A property is a combination of a private field and getters/setters. You can define a property with:
- an absent access modifier (no public, protected or final)
- one or more optional modifiers (static, final, synchronized)
- an optional type
- a mandatory name
Groovy will then generate the getters/setters appropriately.
When you put an explicit access modifier, you are actually using a field, so getters/setters are not generated and that's why the compiler complains about Can't have an abstract method in a non-abstract class, since getters/setters are not there.
来源：https://stackoverflow.com/questions/33107148/can-i-use-groovys-default-getters-setters-to-help-implement-a-java-interface