Discuss / Java / EnumMap 感觉很鸡肋呀
Back

EnumMap 感觉很鸡肋呀

Topic source

两把刷子闯江湖

#1 Created at ... [Delete] [Delete and Lock User]

明明能Enum内部添加字段就可以的事，为啥要创建EnumMap做映射呢？

Map<DayOfWeek,String> enumMap = new EnumMap<DayOfWeek, String>(DayOfWeek.class);
enumMap.put(DayOfWeek.MONDAY,"星期一");
enumMap.put(DayOfWeek.TUESDAY,"星期二");

System.out.println(enumMap.containsValue("星期二"));

System.out.println(Arrays.toString(DayOfWeek.values()));
System.out.println(DayOfWeek.FRIDAY.name());
System.out.println(DayOfWeek.FRIDAY.toString());
System.out.println(DayOfWeek.valueOf("FRIDAY"));

System.out.println(Enum.valueOf(DayOfWeek.class, "MONDAY"));

true

[MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY]

FRIDAY

FRIDAY

FRIDAY

MONDAY

两把刷子闯江湖

#2 Created at ... [Delete] [Delete and Lock User]

public enum DayOfWeek {
MONDAY("1"),
TUESDAY("2"),
WEDNESDAY("3"),
THURSDAY("4"),
FRIDAY("5"),
SATURDAY("6"),
SUNDAY("7");

private String zh;

DayOfWeek(String s) {
this.zh = s;
}
}

MMMMMI

#3 Created at ... [Delete] [Delete and Lock User]

只是个举了个使用例子罢了。

这个翻译器的例子里，map的value是纯常量存进去，这当然直接给枚举加个字段就可以解决

但有没有一种可能map更常用来存取变量呢，当value是一个运行中的变量的时候你怎么提前写在枚举字段里呢

当然enummap也确实用的不算多罢了，完全替换为hashmap也是ok的。enummap只不过因为key为枚举类，枚举对象恰好是唯一的，跟hashmap相比减少了根据key计算内部数组索引的步骤，直接使用枚举序数作为数组索引就可以了

  • 1

Reply