java Enum示例

package com.xx.tests;

import java.util.HashMap;
import java.util.Map;

public enum Season {
	Spring {
		@Override
		public String toString() {
			return "春天";
		}
	},
	Summer{
		@Override
		public String toString() {
			return "夏天";
		}
	},
	Autumn{
		@Override
		public String toString() {
			return "秋天";
		}
	},
	Winter{
		@Override
		public String toString() {
			return "冬天";
		}
	};
	
	private static final Map<Integer,Season> lookup=new HashMap<Integer,Season>();
	static{
		for (Season se : Season.values()) {
			lookup.put(se.ordinal(), se);
		}
	}
	
	public static Season fromOrdinal(int idx){
		return lookup.get(idx);
	}
}

　　

package com.xx.tests;

import java.util.EnumSet;

import org.junit.Test;

public class TestSeason {

	@Test
	public void test() {
		Season sea = Season.Spring;
		System.out.println(sea);
		
		for (Season s : Season.values()) {
			System.out.println(s);
			System.out.println( s.ordinal());
		}
		System.out.println("########");
		Season s1 = Enum.valueOf(Season.class, "Spring");
		System.out.println(s1);
		System.out.println("########");
		System.out.println(Season.fromOrdinal(3));
		
		System.out.println("########");
		EnumSet<Season> es = EnumSet.allOf(Season.class);
		for (Season season : es) {
			System.out.println(season);
		}
		System.out.println("########");
		EnumSet<Season> es2= EnumSet.of(Season.Autumn, Season.Winter);
		for (Season season : es2) {
			System.out.println(season);
		}
	}

}