这篇文章将为大家详细讲解有关Java中枚举类的示例分析,小编觉得挺实用的,因此分享给大家做个参考,希望大家阅读完这篇文章后可以有所收获。
1.枚举类的理解:类的对象只有有限个,确定的。我们称此类为枚举类
2.当需要定义一组常量时,强烈建议使用枚举类
3.如果枚举类中只有一个对象,则可以作为单例模式的实现方式。
方式一:JDK5.0之前,自定义枚举类
public class SeasonTest {
public static void main(String[] args) {
Season spring = Season.SPRING;
System.out.println(spring);
}
}
class Season {
//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.提供当前枚举类的对各对象: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2:提供toString()
@Override
public String toString() {
return "Season{" +
"seasonName='" + seasonName + '\'' +
", seasonDesc='" + seasonDesc + '\'' +
'}';
}
}
方式二:JDK5.0之后,可以使用enum关键字定义枚举类
public class SeasonTest1 {
public static void main(String[] args) {
Season1 summer = Season1.SUMMER;
System.out.println(summer);
System.out.println(Season1.class.getSuperclass());//java.lang.Enum
//values():
Season1[] values = Season1.values();
for (int i = 0; i < values.length; i++) {
System.out.println(values[i]);
}
//valueOf(String objName):返回枚举类中对象时objName的对象。
Season1 winter = Season1.valueOf("WINTER");
//如果没有objName的枚举类对象,则抛异常:IllegalArgumentException
// Season1 winter = Season1.valueOf("WINTER1");
System.out.println(winter);
// winter.show();
}
//使用enum关键字定义枚举类
enum Season1 {
//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");
//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 Season1(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;
}
使用enum关键字定义的枚举类实现接口的情况
情况一:实现接口,在enum类中实现抽象方法
情况二:让枚举类的对象分别实现接口中的抽象方法
public class SeasonTest1 {
public static void main(String[] args) {
//values():
Season1[] values = Season1.values();
for (int i = 0; i < values.length; i++) {
System.out.println(values[i]);
values[i].show();
}
}
interface Info {
void show();
}
enum Season1 implements Info {
SPRING("春天", "春暖花开") {
@Override
public void show() {
System.out.println("春天在哪里");
}
},
SUMMER("夏天", "夏日炎炎") {
@Override
public void show() {
System.out.println("宁夏");
}
},
AUTUMN("秋天", "秋高气爽") {
@Override
public void show() {
System.out.println("秋天不回来");
}
},
WINTER("冬天", "冰天雪地") {
@Override
public void show() {
System.out.println("大约在冬季");
}
};
private final String seasonName;
private final String seasonDesc;
private Season1(String seasonName, String seasonDesc) {
this.seasonName = seasonName;
this.seasonDesc = seasonDesc;
}
public String getSeasonName() {
return seasonName;
}
public String getSeasonDesc() {
return seasonDesc;
}
}
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