Java中所有的枚举类型都是java.lang.Enum的子类。

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1. 定义枚举类型

简单定义一个枚举类型，如下：

public enum Week {
MONDAY,
TUESDAY,
WEDNESDAY,
THURSDAY,
FRIDAY,
SATURDAY,
SUNDAY;
}

2. 枚举类型的常用方法

可以使用枚举类型的values()静态方法返回枚举类型中的所有枚举值，使用枚举常量的name()方法返回枚举常量的名称，使用枚举常量的ordinal()方法返回枚举常量的序数（常量在枚举声明中的位置，从0开始）。

示例代码如下：

public static void main(String[] args) {
//获取枚举类型中的全部枚举值
Week[] days = Week.values();
for(Week day : days) {
//返回枚举常量的名称
String name = day.name();
//返回枚举常量的序数（常量在枚举声明中的位置，从0开始）
int ordinal = day.ordinal();
String toString = day.toString();
Class declaringClass = day.getDeclaringClass();
Class superClass = declaringClass.getSuperclass();
System.out.println(
"Name: " + name
+ "\n"
+ "Ordinal: " + ordinal
+ "\n"
+ "ToString: " + toString
+ "\n"
+ "DeclaringClass: " + declaringClass
+ "\n"
+ "SuperClass: " + superClass
+ "\n"
);
}
}

输出结果如下：

Name: MONDAY
Ordinal: 0
ToString: MONDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: TUESDAY
Ordinal: 1
ToString: TUESDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: WEDNESDAY
Ordinal: 2
ToString: WEDNESDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: THURSDAY
Ordinal: 3
ToString: THURSDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: FRIDAY
Ordinal: 4
ToString: FRIDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: SATURDAY
Ordinal: 5
ToString: SATURDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum

Name: SUNDAY
Ordinal: 6
ToString: SUNDAY
DeclaringClass: class myEnum.Week
SuperClass: class java.lang.Enum