使用反射得到并调用枚举的构造函数

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import static java.lang.System.out;

enum Charge {
    POSITIVE, NEGATIVE, NEUTRAL;
    Charge() {
        out.format("under construction%n");
    }
}

public class EnumTrouble {

    public static void main(String... args) {
        try {
            Class c = Charge.class;

            Constructor[] ctors = c.getDeclaredConstructors();
            for (Constructor ctor : ctors) {
                out.format("Constructor: %s%n", ctor.toGenericString());
                ctor.setAccessible(true);
                ctor.newInstance();
            }

            // production code should handle these exceptions more gracefully
        } catch (InstantiationException x) {
            x.printStackTrace();
        } catch (IllegalAccessException x) {
            x.printStackTrace();
        } catch (InvocationTargetException x) {
            x.printStackTrace();
        }
    }
}