Java枚举

普通枚举

public enum ColorEnum{    red, green, yellow, blue;}

实现带属性和方法的枚举

枚举像普通的类一样可以添加属性和方法, 可以为它添加静态和非静态的属性或方法

public enum SeasonEnum{        spring, summer, autumn, winter;        private final static String position = "test";        public static SeasonEnum getSeason(){            if("test".equals(position)){                return spring;            }else {                return winter;            }        }    }

实现带有构造器的枚举

public enum Gender{        //通过括号赋值,而且必须带有一个参构造器和一个属性方法,否则编译出错        //赋值必须都赋值或都不赋值, 不能一部分赋值一部分不赋值; 如果不赋值        //  则不能写构造器,赋值编译也出错        MAN("MAN"), WOMEN("WOMEN");        private final String value;        //构造器默认也只能是private,从而保证构造函数只能在内部使用        private Gender(String value){            this.value = value;        }        public String getValue(){            return value;        }}

实现带有抽象方法的枚举

public enum OrderState{        /** 已取消 */        CANCEL {public String getName(){return "已取消";}},        /** 待审核 */        WAITCONFIRM {public String getName(){return "待审核";}},        /** 等待付款 */        WAITPAYMENT {public String getName(){return "等待付款";}},        /** 正在配货 */        ADMEASUREPRODUCT {public String getName(){return "正在配货";}},        /** 等待发货 */        WAITDELIVER {public String getName(){return "等待发货";}},        /** 已发货 */        DELIVERED {public String getName(){return "已发货";}},        /** 已收货 */        RECEIVED {public String getName(){return "已收货";}};        public abstract String getName();}

举例

ColorEnum colorEnum = ColorEnum.red;    switch (colorEnum) {        case red:        System.out.println("color is red");        break;    case green:        System.out.println("color is green");        break;    case yellow:        System.out.println("color is yellow");        break;    case blue:        System.out.println("color is blue");        break;}//遍历枚举for(ColorEnum color : ColorEnum.values()){     System.out.println(color);}//获取枚举的个数System.out.println("ColorEnum枚举中的值有"+ColorEnum.values().length+"个");//获取枚举的索引位置，默认从0开始System.out.println(ColorEnum.red.ordinal());//0System.out.println(ColorEnum.green.ordinal());//1System.out.println(ColorEnum.yellow.ordinal());//2System.out.println(ColorEnum.blue.ordinal());//3//枚举默认实现了java.lang.Comparable接口System.out.println(ColorEnum.red.compareTo(ColorEnum.green));System.err.println("季节为" + SeasonEnum.getSeason());for(Gender gender : Gender.values()){    System.out.println(gender.value);}//实现抽象方法for(OrderState order : OrderState.values()){    System.out.println(order.getName());}