常量是一旦定义就不可修改的值,在开发中,如果有多个常量,需要定义多个常量;如: public static final String MONDAY="周一"; public static final String TUESDAY ="周二"; public static final String WEDNESDAY="周三"; public static final String THURSDAY="周四"; public static final String FRIDAY="周五; public static final String SATURDAY ="周六"; public static final String SUNDAY ="周日";这样定义,显然比较费劲,枚举你可以理解为是对常量的封装,它是一个特殊的类。可以有自己自定义的方法,自定义的属性和构造函数。其次,变量的类型可以是枚举类型,这样就限定了变量的取值范围。如: 定义一个枚举 public enum WEEK{ MONDAY("周一"),TUESDAY(),WEDNESDAY,THURSDAY,FRIDAY,SATURDAY,SUNDAY; //定义私有构造函数,给这些常量赋值 private String str;
public String getStr(){ return this.str; } }定义一个变量为枚举类型 WEEK w = WEEK.MONDAY; System.out.println(s.getStr());
SUCCEED(1,“成功”), FAIL(2,"失败");
public int getIndex() {
return index;
}
public void setIndex(int index) {
this.index = index;
}
private int index;
private String text;
private Status(int index, String text) {
this.index = index;
this.text=text;
}
}
public static final String MONDAY="周一";
public static final String TUESDAY ="周二";
public static final String WEDNESDAY="周三";
public static final String THURSDAY="周四";
public static final String FRIDAY="周五;
public static final String SATURDAY ="周六";
public static final String SUNDAY ="周日";这样定义,显然比较费劲,枚举你可以理解为是对常量的封装,它是一个特殊的类。可以有自己自定义的方法,自定义的属性和构造函数。其次,变量的类型可以是枚举类型,这样就限定了变量的取值范围。如:
定义一个枚举
public enum WEEK{
MONDAY("周一"),TUESDAY(),WEDNESDAY,THURSDAY,FRIDAY,SATURDAY,SUNDAY;
//定义私有构造函数,给这些常量赋值
private String str;
public String getStr(){
return this.str;
}
}定义一个变量为枚举类型
WEEK w = WEEK.MONDAY;
System.out.println(s.getStr());