System.out.println(Color.valueOf("RED"));//此行代码会返回IllegalArgumentException 异常,因为Color枚举类里没有名为WHITE的常量System.out.println(Color.valueOf("WHITE")); } } 参考文献 https://docs.oracle.com/javase/tutorial/java/javaOO/enum.html https://www.geeksforgeeks.org/enum-in-java/ ...
ENUM_VALUE_3}publicExampleEnumconvertStringToEnum(StringinputString){try{returnExampleEnum.valueOf(inputString);}catch(IllegalArgumentExceptione){// 处理转换失败的情况returnnull;}}publicbooleancompareEnumWithString(ExampleEnumenumValue,StringcompareString){if(enumValue!=null){returnenumValue.toString().equ...
enumConstantDirectory().get(name); if (result != null) return result; if (name == null) throw new NullPointerException("Name is null"); throw new IllegalArgumentException( "No enum constant " + enumType.getCanonicalName() + "." + name); } 上图中第一种为编译器生成的 valueOf 函数...
Java 中的枚举类型采用关键字enum 来定义,从JDK 1.5才有的新类型,所有的枚举类型都是继承自Enum 类型,所以枚举类不能指定继承的父类,但是可以实现多个接口,枚举类默认实现了Comparable接口和Serializable接口,而且与普通的类最大的区别在于:枚举类的构造方法的访问权限只能为私有的且对应的实例必须显示列举出来(即对应...
publicstatic<TextendsEnum<T>> TvalueOf(Class<T> enumType,String name){Tresult=enumType.enumConstantDirectory().get(name);if(result !=null)returnresult;if(name ==null)thrownewNullPointerException("Name is null");thrownewIllegalArgumentException("No enum const "+ enumType +"."+ name); ...
publicenumDay{MON DAY(1),TUES DAY(2);privateintvalue;privateDay(intvalue){this.value=value;}}#Output:# MONDAY=1# TUESDAY=2 Java Copy In this example, we’ve defined an enumDaywith two constants:MONDAYandTUESDAY. Each constant is assigned a specific value through the enum’s constructor....
Createenum constructorwhich accepts multiple values Assigneach constructor argument to a member fieldin the enum definition Creategetter methodsso we can access any of the values assigned to a particular enum constant Create areverse lookupmethod so we can get the enum constant from any given enum ...
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...
java.lang.IllegalArgumentException: No enum constant com.stubbornjava.examples.common.EnumLookup.CardSuit.Missing at java.lang.Enum.valueOf(Enum.java:238) at com.stubbornjava.examples.common.EnumLookup$CardSuit.valueOf(EnumLookup.java:1)
(), field.get(anEnum)); } catch (IllegalArgumentException | IllegalAccessException e) { e.printStackTrace(); } } // 将Map添加到集合中 resultList.add(map); } return resultList; } public static void main(String[] args) { // 枚举类 System.out.println(enumToListMap(EducateStatusEnum....