最好不要用序数来索引数组，而要使用EnumMap

EnumMap源代码学习

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 public V put(K key, V value) {
        typeCheck(key);

        int index = key.ordinal();
        Object oldValue = vals[index];
        vals[index] = maskNull(value);
        if (oldValue == null)
            size++;
        return unmaskNull(oldValue);
    }

 public V remove(Object key) {
        if (!isValidKey(key))
            return null;
        int index = ((Enum<?>)key).ordinal();
        Object oldValue = vals[index];
        vals[index] = null;
        if (oldValue != null)
            size--;
        return unmaskNull(oldValue);
 }

public V get(Object key) {
        return (isValidKey(key) ?
                unmaskNull(vals[((Enum<?>)key).ordinal()]) : null);
    }

 public boolean containsKey(Object key) {
        return isValidKey(key) && vals[((Enum<?>)key).ordinal()] != null;
    }

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package com.canal.demo;

import com.alibaba.fastjson.JSON;
import com.google.common.collect.Lists;

import java.util.EnumMap;
import java.util.List;

public class ZookeeperHello {



	private static enum Operation{
		ADD(2),
		DIVIDE(4),
		MULTIPLY(8),
		SUB(16);

		private int code;

		Operation(int code) {
			this.code = code;
		}

		public int getCode() {
			return code;
		}

	}


	public static void main(String[] args) {

		EnumMap<Operation,List<String>> map =new EnumMap<Operation, List<String>>(Operation.class);

		map.put(Operation.ADD, Lists.newArrayList("ADD","添加"));
		map.put(Operation.MULTIPLY, Lists.newArrayList("MULTIPLY","乘法"));

		System.out.println(JSON.toJSONString(map));


	}
}