Java Enum的七种用法

枚举

枚举是由class来实现的（继承Enum类,所以不能再继承其他类，也不能被继承，但是可用来实现接口)。因此由enum可以实现很多class的内容，包括可以有member和member function

1.常量

public enum Color{
    RED,
    GREEN,
    BLANK,
    YELLOW
}

2.switch

Color color=new Color();
switch(color){
    case RED:
        break;
    case GREEN:
        break;
    case YELLOW:
        break;
    case BLANK:
        break;
    case YELLOW:
        break;
}

3.方法

public enum Color{
    RED,
    GREEN,
    BLANK,
    YELLOW

    private String name;
    private int index;
    private Color(String name,int index){
        this.name=name;
        this.index=index;
    }
    public void setName(String name){
        this.name=name;
    }
    public void setIndex(int index){
        this. index=index;
    }
    public String getName(){
        return name;
    }
    public int getIndex(){
        return index;
    }
}

4.覆盖枚举中的方法

public enum Color{
    RED,
    GREEN,
    BLANK,
    YELLOW

    private String name;
    private int index;
    private Color(String name,int index){
        this.name=name;
        this.index=index;
    }
    public void setName(String name){
        this.name=name;
    }
    public void setIndex(int index){
        this. index=index;
    }
    public String getName(){
        return name;
    }
    public int getIndex(){
        return index;
    }
    @override
    public  String toString(){
        return this.index+"  "+this.name;
    }
}

5.实现接口

public interface Behaviour{
    void print();
}
public enum Color implements Behaviour{
    RED,
    GREEN,
    BLANK,
    YELLOW

    private String name;
    private int index;
    private Color(String name,int index){
        this.name=name;
        this.index=index;
    }
    public void setName(String name){
        this.name=name;
    }
    public void setIndex(int index){
        this. index=index;
    }
    public String getName(){
        return name;
    }
    public int getIndex(){
        return index;
    }
    @override
    public  String toString(){
        return this.index+"  "+this.name;
    }
    @override
    public void print(){
        System.out.println(this.toString());
    }
}

6.使用接口组织枚举

public interface Food{
    enum Coffee implements Food{
        BLACK_COFFEE,DECAF_COFFEE
    }
}

7.枚举集合

EnumSet、EnumMap