117笔记问答在Java中，枚举类型使用enum关键字来定义。枚举类型可以包含常量、方法和构造函数。以下是枚举类型的一些使用方法：
- 定义枚举类型：
public enum Day {
MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}
- 访问枚举常量：
Day day = Day.MONDAY; System.out.println(day); // 输出 MONDAY
- 使用枚举类型中的方法：
public enum Day {
MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY;
public boolean isWeekend() {
return this == SATURDAY || this == SUNDAY;
}
}
Day day = Day.SATURDAY;
System.out.println(day.isWeekend()); // 输出 true
- 使用
values()方法获取枚举常量数组：
Day[] days = Day.values();
for (Day day : days) {
System.out.println(day);
}
- 使用
valueOf()方法根据字符串获取枚举常量：
Day day = Day.valueOf("MONDAY");
System.out.println(day); // 输出 MONDAY
- 实现枚举类型的构造函数和方法：
public enum Day {
MONDAY("Monday"), TUESDAY("Tuesday"), WEDNESDAY("Wednesday"), THURSDAY("Thursday"), FRIDAY("Friday"), SATURDAY("Saturday"), SUNDAY("Sunday");
private String displayName;
Day(String displayName) {
this.displayName = displayName;
}
public String getDisplayName() {
return displayName;
}
}
Day day = Day.MONDAY;
System.out.println(day.getDisplayName()); // 输出 Monday