Adding a concrete method in an enum is similar to adding the same method in any other class. We can use any access specifier e.g.public,privateorprotected. We can return values from enum methods or simply use them to perform internal logic. publicenumDirection{EAST,WEST,NORTH,SOUTH;protected...
public static String toJson(Class<? extends Enum> enumClass) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException { Method methodValues = enumClass.getMethod("values"); Object invoke = methodValues.invoke(null); int length = java.lang.reflect.Array.getLength(invoke); List<...
packagecom.darksnow.enums;importjava.lang.annotation.Documented;importjava.lang.annotation.ElementType;importjava.lang.annotation.Retention;importjava.lang.annotation.RetentionPolicy;importjava.lang.annotation.Target;//TYPE(在此代码中表示可以在类上,接口上,枚举上,注解上使用MyAnnotation注解)//METHOD(表示可以在...
枚举(enum)类型是Java 5新增的特性,它是一种新的类型,允许用常量来表示特定的数据片断,而且全部都以类型安全的形式来表示。 初探枚举类 在程序设计中,有时会用到由若干个有限数据元素组成的集合,如一周内的星期一到星期日七个数据元素组成的集合,由三种颜色红、黄、绿组成的集合,一个工作班组内十个职工组成的...
在OSGI框架中,每一个Bundle实际上都是可热插拔的,因此,对一个特定的Bundle进行修改不会影响到容器中的所有应用,运行的大部分应用还是可以照常工作。当你将修改后的Bundle再部署上去的时候,容器从来没有重新启过。这种可动态更改状态的特性在一些及时性很强的系统中比较重要,尤其是在Java Web项目中,无需重启应用服务...
Methods of Java Enum Class There are some predefined methods in enum classes that are readily available for use. 1. Java Enum ordinal() The ordinal() method returns the position of an enum constant. For example, ordinal(SMALL) // returns 0 2. Enum compareTo() The compareTo() method com...
To get a single enum value (e.g., get production URL from enum constant), use thegetUrl()method that we created. StringprodUrl=Environment.PROD.getUrl();System.out.println(prodUrl); Output: https://prod.domain.com:1088/ 4. Getting Enum by Name ...
Theenumkeyword was introduced in Java 5 Constants defined this way make the code more readable 2.1 枚举的典型应用场景 错误码、状态机等 将常量放到一起,便于管理。 2.2 枚举的本质 其实就是枚举Enum的子类 2.3 怎么看java编译出的class javac xxx.java 来生成.class ...
* isn't necessary or desirable. An enum type should override this * method when a more "programmer-friendly" string form exists. * * @return the name of this enum constant */ public String toString() { return name; } 1. 2.
Creates an enum set initially containing the specified element. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an...