Enums in Java are a type of class that have a fixed number of instances. These instances, also known as constants, can be assigned values. This can be done by defining a constructor and a private variable in the enum. The constructor allows us to initialize the enum constants with specifi...
EnumWithMultipleValues.java importjava.util.Arrays;importjava.util.Optional;publicclassEnumWithMultipleValues{publicstaticvoidmain(String[]args){//Print all enum and valuesfor(AccountStatusas:AccountStatus.values()){System.out.println("Status "+as.getCode()+" is : "+as.getFullName());}//Rever...
publicstatic<TextendsEnum<T>>TvalueOf(Class<T>enumType,Stringname){returnEnum.valueOf(enumType,name);} 1. 2. 3. 上述代码通过反射的valueOf()方法来获取指定枚举类型的值。其中,enumType参数是枚举类型的Class对象,name参数是要获取的枚举值的名称。该方法会返回一个枚举值,如果找不到对应的值,则会抛...
每个枚举类型都继承自java.lang.Enum,并自动添加了values和valueOf方法。 而每个枚举常量是一个静态常量字段,使用内部类实现,该内部类继承了枚举类。所有枚举常量都通过静态代码块来进行初始化,即在类加载期间就初始化。 另外通过把clone、readObject、writeObject这三个方法定义为final的,同时实现是抛出相应的异常。这样...
1 public abstract class Enum<E extends Enum<E>> 2 implements Comparable<E>, Serializable { 3 ... 4 } 1. 2. 3. 4. 查看这个类的实现,果然是没有values()方法的。 接下来我们通过命令行进入到EnumTest.java文件所在目录,在此使用javac命令编译这个文件: javac...
It can only be assigned with 4 values. pizzaSize = Size.SMALL; pizzaSize = Size.MEDIUM; pizzaSize = Size.LARGE; pizzaSize = Size.EXTRALARGE; Example 2: Java Enum with the switch statement enum Size { SMALL, MEDIUM, LARGE, EXTRALARGE } class Test { Size pizzaSize; public Test(Size ...
};publicstatichr.test.Color[] values();//实现Enum类的抽象方法publicstaticcom.dxz.enumtest.Color valueOf(java.lang.String arg0); } 下面我们就详细介绍enum定义的枚举类的特征及其用法。(后面均用Color举例) 1、Color枚举类就是class,而且是一个不可以被继承的final类。其枚举值(RED,BLUE...)都是Color...
values() 返回枚举类的所有常量; ordinal() 返回枚举常量的序号 valueOf(String name) 返回名为name的枚举常量,如果存在。 //演示 values(), ordinal() 和 valueOf() 方法enumColor { RED, GREEN, BLUE; }publicclassTest {publicstaticvoidmain(String[] args) ...
Let’s modify the ‘Day’ enum we used earlier and add a feature that assigns a type to each day — weekdays or weekends. This new feature can be implemented using Java enum with values. Here’s how you can do it: public enum Day { ...
All the constants of an enum class can be obtained by calling the implicit public static T[] values() method of that class. Added in 1.5. Java documentation for java.lang.Enum.valueOf(java.lang.Class<T>, java.lang.String). Portions of this page are modifications based on work created ...