一、定义enum抽象类
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public class AbstractEnum { private static final Map<String, AbstractEnum> nameEnumMap = new ConcurrentHashMap<>(); @Getter protected String name; protected AbstractEnum () { } protected AbstractEnum(String name) { this.name = name; if (!nameEnumMap.containsKey(name)) { nameEnumMap.put(name, this); } } public boolean equals(AbstractEnum abstractEnum) { return this.name == null || abstractEnum == null ? false : this.name.equals(abstractEnum.getName()); } public String toString() { return this.name; } public static AbstractEnum valueOf(String name) { if (name == null) throw new NullPointerException("Name is null"); AbstractEnum result = nameEnumMap.get(name); if (result != null) { return result; } throw new IllegalArgumentException( "No enum constant exists, name is." + name); } public static void init() { } } |
二、实际继承enum，与enum使用方法一致
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public class TypeEnum extends AbstractEnum { private static final Map<String, TypeEnum> nameEnumMap = new ConcurrentHashMap<>(); protected TypeEnum(String name) { super(name); if (!nameEnumMap.containsKey(name)) { nameEnumMap.put(name, this); } } public static TypeEnum valueOf(String name) { if (name == null) throw new NullPointerException("Name is null"); TypeEnum result = nameEnumMap.get(name); if (result != null) { return result; } throw new IllegalArgumentException( "No enum constant exists, name is." + name); } public static final TypeEnum TYPE_ONE = new TypeEnum("TYPE_ONE");} |
三、可继续继承枚举，进行枚举分类。
补充：Java中自定义枚举（Enum）项的值,可设置为指定的值
一、代码
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package base.lang;/** * ClassName: StateEnum * @Description: TODO * @author fuming * @date 2016年11月27日 */public enum StateEnum{//添加枚举的指定常量online(10),offline(20);//必须增加一个构造函数,变量,得到该变量的值private int mState=0;private StateEnum(int value){mState=value;}/*** @return 枚举变量实际返回值*/ public int getState() { return mState; } } |
二、示例
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//enumStateEnum orderState=StateEnum.offline;//orderState=StateEnum.online;System.out.println("state="+ orderState.getState()); |
三、打印结果
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state=20 //测试正常 |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。如有错误或未考虑完全的地方，望不吝赐教。
原文链接：https://blog.csdn.net/jiangxuexuanshuang/article/details/87911048
