文章目录
Tips 与接口不同，enum中的public static final是必须省去的enum继承于java.lang.Enum 常用方法 values()：返回枚举类型的对象数组。该方法可以很方便地遍历所有的 枚举值。valueOf(String str)：可以把一个字符串转为对应的枚举类对象。要求字符 串必须是枚举类对象的“名字”。如不是，会有运行时异常： IllegalArgumentException。toString()：返回当前枚举类对象常量的名称
public class Test { public static void main(String[] args) { //values():返回所有的枚举类对象构成的数组 Season[] values = Season.values(); for(int i = 0;i < values.length;i++){ System.out.println(values[i]); } //valueOf(String objName):返回枚举类中对象名是objName的对象。 //如果没有objName的枚举类对象，则抛异常：IllegalArgumentException Season winter = Season.valueOf("WINTER"); System.out.println(winter); }}enum Season { SPRING, SUMMER, AUTUMN, WINTER}
示例 自定义枚举类（jdk5.0之前）public class SeasonTest { public static void main(String[] args) { Season spring = Season.SPRING; System.out.println(spring);//输出Season类中重写的toString()，不重写的话输出地址值 }}//自定义枚举类class Season{ //注意此处是class开头 //1.声明Season对象的属性:private final修饰 private final String seasonName; private final String seasonDesc; //2.私有化类的构造器,并给对象属性赋值 private Season(String seasonName,String seasonDesc){ this.seasonName = seasonName; this.seasonDesc = seasonDesc; } //3.提供当前枚举类的多个对象：public static final的 public static final Season SPRING = new Season("春天","春暖花开"); public static final Season SUMMER = new Season("夏天","夏日炎炎"); public static final Season AUTUMN = new Season("秋天","秋高气爽"); public static final Season WINTER = new Season("冬天","冰天雪地"); //4.其他诉求1：获取枚举类对象的属性 public String getSeasonName() { return seasonName; } public String getSeasonDesc() { return seasonDesc; } //4.其他诉求1：提供toString() @Override public String toString() { return "Season{" + "seasonName='" + seasonName + ''' + ", seasonDesc='" + seasonDesc + ''' + '}'; }}
enum关键字定义枚举类（jdk5.0）public class Test { public static void main(String[] args) { Season summer = Season.SUMMER; System.out.println(summer.toString()); //返回枚举类对象的名称 System.out.println(Season.class.getSuperclass());//class java.lang.Enum }}//使用enum关键字枚举类enum Season{ //1.提供当前枚举类的对象，多个对象之间用","隔开，末尾对象";"结束 SPRING("春天","春暖花开"), SUMMER("夏天","夏日炎炎"), AUTUMN("秋天","秋高气爽"), WINTER("冬天","冰天雪地"); //2.声明Season对象的属性:private final修饰 private final String seasonName; private final String seasonDesc; //2.私有化类的构造器,并给对象属性赋值 private Season(String seasonName,String seasonDesc){ this.seasonName = seasonName; this.seasonDesc = seasonDesc; } //4.其他诉求1：获取枚举类对象的属性 public String getSeasonName() { return seasonName; } public String getSeasonDesc() { return seasonDesc; }}
枚举类实现接口public class SeasonTest { public static void main(String[] args) { Season spring = Season.valueOf("SPRING"); spring.show(); }}interface Info{ void show();}enum Season implements Info{ SPRING(){ @Override public void show() { System.out.println("春天在哪里？"); } }, SUMMER(){ @Override public void show() { System.out.println("夏日炎炎"); } };}