1.枚举类的使用
-
当需要使用一组常量时,建议使用枚举类
-
自定义枚举类
package javabasis.chapter10;
public class Season {
private final String SEASONNAME;//季节名称
private final String SEASONDESC;//季节描述
private Season(String seasonName,String seasonDesc)
{
this.SEASONNAME=seasonName;
this.SEASONDESC=seasonDesc;
}
public static final Season SPRING=new Season("春天","春暖花开");
public static final Season SUMMER=new Season("夏天","骄阳似火");
public static final Season AUTUMN=new Season("秋天","秋高气爽");
public static final Season WINTER=new Season("冬天","白雪皑皑");
public String toString()
{
return SEASONNAME+" "+SEASONDESC;
}
public static void main(String[] args) {
System.out.println(SPRING);
System.out.println(SUMMER);
System.out.println(AUTUMN);
System.out.println(WINTER);
}
}
天 春暖花开
夏天 骄阳似火
秋天 秋高气爽
冬天 白雪皑皑
- 自定义枚举类
package javabasis.chapter10;
public enum SeasonEnum {
SPRING("春天","春暖花开"),
SUMMER("夏天","骄阳似火"),
AUTUMN("秋天","秋高气爽"),
WINTER("冬天","白雪皑皑");
private final String SEASONNAME;//季节名称
private final String SEASONDESC;//季节描述
private SeasonEnum(String seasonName,String seasonDesc)//构造器结构与枚举量一致
{
this.SEASONNAME=seasonName;
this.SEASONDESC=seasonDesc;
}
public static void main(String[] args) {
System.out.println(SPRING);
System.out.println(SPRING.SEASONNAME);
System.out.println(SPRING.SEASONDESC);
}
}
SPRING
春天
春暖花开
2.注解
- @Override:限定重写父类方法,该注解只能用于方法
- @Deprecated:用于表示所修饰的元素、类、方法已经过时
- @SuppressWarning:抑制编译器警告
几种元注解:
-
@Target 描述注解的使用范围
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@Retention 描述注解保留的时间范围
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@Documented 描述在使用 javadoc 工具为类生成帮助文档时是否要保留其注解信息。
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@Inherited 使被它修饰的注解具有继承性(如果某个类使用了被@Inherited修饰的注解,则其子类将自动具有该注解)。