2、枚举

方法1：

1、Fruit.java

/**
 * 水果的枚举类
 * @author Administrator
 *
 */
public enum Fruit {
    //apple调用有两个参数的构造，构造可以跟匿名内部类
    apple(6,3){
        public String fname(){
            return "苹果";
            }
        },
    orange{
        public String fname(){
            return "橘子";
            }
        },
    peat{
        public String fname(){
            return "梨";
            }
        },
    banana{
        public String fname(){
            return "香蕉";
            }
        };
    private int num;//个数
    private int price;//价格
    

    private Fruit() {
    }
    private Fruit(int num , int price) {
        this.num = num;
        this.price = price;
    }
    
    //抽象方法，返回水果的名字
    public abstract String fname();
    
    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

}

2、FruitTest.java

public class FruitTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Fruit apple = Fruit.apple;
        System.out.println("有"+apple.getNum()+
                "个"+apple.fname()+
                "共"+apple.getPrice()+"元");
    }

}

方法2：

1、Week1.java

public class Week1 {
    public static final int MON = 1;
    public static final int TUS = 2;
    public static final int WED = 3;
    public static final int THU = 4;
    public static final int FIR = 5;
    public static final int SAT = 6;
    public static final int SUN = 7;
}

2、Test.java

public class Test {
    public static void main(String[] args) {
        Week2 day = Week2.MON;
        Test test = new Test();
        test.week(day);
    }
    
    public void week(Week2 day){
        switch (day) {
        case MON:
            System.out.println("星期一，上课");
            break;

        default:
            System.out.println("输入错误！");
            break;
        }
    }
}

方法3：

1、Week2.java

public enum Week2 {
    //每个枚举常量都相当于一个对象
    MON,TUS,WED,THU,FIR,SAT,SUN
}

2、

public class Test2 {
    public enum Fruite{
        apple(6,3),orange(4,2),banana(5,4),peat(7,5);
        
        private Fruite() {
        }
        
        private Fruite(int price , int num) {
            this.price = price;
            this.num = num;
            
        }

        private int price;
        private int num;
        
        public int getNum() {
            return num;
        }

        public void setNum(int num) {
            this.num = num;
        }

        public int getPrice() {
            return price;
        }

        public void setPrice(int price) {
            this.price = price;
        }
    }
    public static void main(String[] args) {
        Fruite apple = Fruite.apple;
        System.out.println("苹果的价格："+apple.price+"苹果的数量："+apple.num);
    }
}