java 枚举

1.枚举无变量参数

public enum SeasonEnum{
    SPRING,SUMMER,AUTUMN,WINTER;
}

public void test()
{
    SeasonEnum se = SeasonEnum.SPRING;
    switch(se) {
    case SPRING:
        System.out.println("spring");
        break;
    case SUMMER:
        System.out.println("summer");
        break;
    case AUTUMN:
        System.out.println("autumn");
        break;
    case WINTER:
        System.out.println("winter");
        break;
    }
}    

2.只传一个值

public enum SeasonEnum{
    SPRING("1"),SUMMER("2"),AUTUMN("3"),WINTER("4");
    
    private String val;
    SeasonEnum (String val){
        this.val = val;
    }
    
    public String getVal()
    {
        return val;
    }
}

public void test()
{
    SeasonEnum se = SeasonEnum.SUMMER;
    System.out.println(se.getVal()); // 2
}

3.传入键值

public enum SeasonEnum{
    SPRING(0,"spring"),SUMMER(1,"summer"),AUTUMN(2,"autumn"),WINTER(3,"winter");
    private int key;
    private String val;
    
    public int getKey() {
        return key;
    }
    
    public String getVal() {
        return val;
    }
    
    SeasonEnum (int key, String val){
        this.key = key;
        this.val = val;
    }
}

public void test()
{
    SeasonEnum se = SeasonEnum.WINTER;
    System.out.println(se.getKey()+" -> " + se.getVal()); //  3 -> winter
}