枚举的封装

参考地址1：https://blog.csdn.net/qq_35385687/article/details/90147104
参考地址2：http://blog.lichengwu.cn/java/2011/09/26/the-usage-of-enum-in-java/

enum-modifiers enum enumname:enum-base{
    enum-body,
}

//性别的枚举类型
enum SexEnum{
    male,female;
}
//表示颜色的枚举类型
enum Color{
    RED,BLUE,GREEN,BLACK,YELLOW;
}

public class EnumDemo {
    Color color=Color.RED;

    public void change(){
        switch(color){
            case RED:
                color=Color.GREEN;
                break;
            case YELLOW:
                color=Color.RED;
                break;
            case GREEN:
                color=Color.YELLOW;
                break;
        }
    }
    public static void main(String[] args) {
        //所有枚举实例都可以调用 Enum 类的方法
        System.out.println(SexEnum.male);//输出结果：male
        System.out.println(SexEnum.female);//输出结果：female

        EnumDemo enumDemo = new EnumDemo();
        enumDemo.change();
        System.out.println(enumDemo.color);//输出结果：GREEN
    }
}

enum SeasonEnum {
    SPRING, SUMMER, FALL, WINTER;
}
public class EnumDemo2 {
    public static void main(String[] args) {
        SeasonEnum a;//定义枚举类型变量a，用于接收valueOf()方法的返回值
        a=SeasonEnum.valueOf("SPRING");//valueOf()方法调用者为枚举类，此处为SeasonEnum；
        System.out.println(a.name());//SPRING
        // 形参只需一个——枚举值名称，注意是String类型，要加双引号，此处为"SPRING"
        System.out.println(a.compareTo(SeasonEnum.SPRING));//通过a调用实例方法compareTo()，输出0，表明a为枚举值SPRING
    }
}

//定义一个枚举类型
enum Signal{
    GREEN,YELLOW,RED;
}
public static void main(String[] args){
    for(int i=0;i<Signal.values().length;i++)    {
        System.out.println("枚举成员："+Signal.values()[i]);
    }
}

枚举成员：GREEN 
枚举成员：YELLOW 
枚举成员：RED

public enum Sex {
   //定义一个枚举
   male,female;
}
public class TestEnum {
    public static void main(String[] args) {
        compare(Sex.valueOf("male"));    //比较
    }

    public static void compare(Sex s) {
        for(int i=0;i<Sex.values().length;i++){
            System.out.println(s+"与"+Sex.values()[i]+"的比较结果是："+s.compareTo(Sex.values()[i]));
        }
    }
}

male与male的比较结果是：0
male与female的比较结果是：-1

public class TestEnum1{
    enum Signal{
        //定义一个枚举类型
        GREEN,YELLOW,RED;
    }

    public static void main(String[] args)    {
        for(int i=0;i<Signal.values().length;i++){
            System.out.println("索引"+Signal.values()[i].ordinal()+"，值："+Signal.values()[i]);
        }
    }
}

索引0，值：GREEN
索引1，值：YELLOW
索引2，值：RED

enum WeekDay{    
　　 Mon("Monday"),
　　 Tue("Tuesday"),
　　 Wed("Wednesday"),
　　 Thu("Thursday"),
　　 Fri("Friday"),
　　 Sat("Saturday"),
　　 Sun("Sunday");

    //以上是枚举的成员，必须先定义，而且使用分号结束
    private final String day;
    private WeekDay(String day){
        this.day=day;
    }
    public static void printDay(int i) {
        switch(i) {
            case 1:
                System.out.println(WeekDay.Mon);
                break;
            case 2:
                System.out.println(WeekDay.Tue);
                break;
            case 3:
                System.out.println(WeekDay.Wed);
                break;
            case 4:
                System.out.println(WeekDay.Thu);
                break;
            case 5:
                System.out.println(WeekDay.Fri);
                break;
            case 6:
                System.out.println(WeekDay.Sat);
                break;
            case 7:
                System.out.println(WeekDay.Sun);
                break;
            default:
                System.out.println("wrong number!");
        }
    }
    public String getDay() {
        return day;
    }
}

public static void main(String[] args){
    for(WeekDay day:WeekDay.values()){
        System.out.println(day+"====>"+day.getDay());
    }
    WeekDay.printDay(5);
}

Mon====>Monday
Tue====>Tuesday
Wed====>Wednesday
Thu====>Thursday
Fri====>Friday
Sat====>Saturday
Sun====>Sunday
Fri

public class Test{
    public enum Color {
        RED("红色",1),
　　　　 GREEN("绿色",2),
　　　　 WHITE("白色",3),
　　　　 YELLOW("黄色",4);

        //成员变量
        private String name;
        private int index;
        //构造方法
        private Color(String name,int index) {
            this.name=name;
            this.index=index;
        }
        //覆盖方法
        @Override
        public String toString() {
            return this.index+"-"+this.name;
        }
    }
    public static void main(String[] args) {
        System.out.println(Color.RED.toString());    //输出：1-红色
    }
}

//定义数据库类型枚举
public enum DataBaseType{
    MYSQUORACLE,
　　DB2,
　　SQLSERVER；
}

//某类中定义的获取数据库URL的方法以及EnumMap的声明
private EnumMap<DataBaseType,String> urls=new EnumMap<DataBaseType,String>(DataBaseType.class);
public DataBaseInfo(){
    urls.put(DataBaseType.DB2,"jdbc:db2://localhost:5000/sample");
    urls.put(DataBaseType.MYSQL,"jdbc:mysql://localhost/mydb");
    urls.put(DataBaseType.ORACLE,"jdbc:oracle:thin:@localhost:1521:sample");
    urls.put(DataBaseType.SQLSERVER,"jdbc:microsoft:sqlserver://sql:1433;Database=mydb");
}

//根据不同的数据库类型，返回对应的URL
//@param type DataBaseType 枚举类新实例
//@return
public String getURL(DataBaseType type){
    return this.urls.get(type);
}

interface Behaviour {
    void print();
    String getInfo();
}
interface Behaviour2 {
}
public enum EnumDemo implements Behaviour,Behaviour2{
    RED("红色", 1), 
    GREEN("绿色", 2), 
    BLANK("白色", 3), 
    YELLO("黄色", 4);
    
    // 成员变量
    private String name;
    private int index;
    // 构造方法
    private EnumDemo(String name, int index) {
        this.name = name;
        this.index = index;
    }
    //接口方法
    @Override
    public String getInfo() {
        return this.name;
    }
    //接口方法
    @Override
    public void print() {
        System.out.println(this.index+":"+this.name);
    }

    public static void main(String[] args) {
        EnumDemo.RED.print();
    }
}

public interface Food {  
    enum Coffee implements Food{  
        BLACK_COFFEE,DECAF_COFFEE,LATTE,CAPPUCCINO  
    }  
    enum Dessert implements Food{  
        FRUIT, CAKE, GELATO  
    }  
}