使用反射枚举常量字段

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Member;
/*
N o w J a v a . c o m - 时代Java
*/

import java.util.List;

import java.util.ArrayList;

import static java.lang.System.out;


public class EnumSpy {

    private static final String fmt = "  %11s:  %s %s%n";


    public static void main(String... args) {

        try {

            Class<?> c = Class.forName(args[0]);/* from N o w J a v a . c o m - 时  代  Java*/

            if (!c.isEnum()) {

                out.format("%s is not an enum type%n", c);

                return;

            }

            out.format("Class:  %s%n", c);


            Field[] flds = c.getDeclaredFields();

            List<Field> cst = new ArrayList<Field>(); // enum constants

            List<Field> mbr = new ArrayList<Field>(); // member fields

            for (Field f : flds) {

                if (f.isEnumConstant())

                    cst.add(f);

                else

                    mbr.add(f);

            }

            if (!cst.isEmpty())

                print(cst, "Constant");

            if (!mbr.isEmpty())

                print(mbr, "Field");


            Constructor[] ctors = c.getDeclaredConstructors();

            for (Constructor ctor : ctors) {

                out.format(fmt, "Constructor", ctor.toGenericString(),

                        synthetic(ctor));

            }


            Method[] mths = c.getDeclaredMethods();

            for (Method m : mths) {

                out.format(fmt, "Method", m.toGenericString(), synthetic(m));

            }


            // production code should handle this exception more gracefully

        } catch (ClassNotFoundException x) {

            x.printStackTrace();

        }

    }


    private static void print(List<Field> lst, String s) {

        for (Field f : lst) {

            out.format(fmt, s, f.toGenericString(), synthetic(f));

        }

    }


    private static String synthetic(Member m) {

        return (m.isSynthetic() ? "[ synthetic ]" : "");

    }

}