练习一

案例：使用枚举类实现单例模式

package chapter08_oop3_teacher.src.com.atguigu10._enum.exer1;/*** ClassName: BankTest1* Description:** @Author 尚硅谷-宋红康* @Create 15:05* @Version 1.0*/
public class BankTest1 {public static void main(String[] args) {
//        Bank1.instance = null;System.out.println(GirlFriend.XIAO_LI);}
}//jdk5.0之前的使用枚举类定义单例模式
class Bank1{private Bank1(){}public static final Bank1 instance = new Bank1();}
//jdk5.0使用enum关键字定义枚举类的方式定义单例模式
enum Bank2{CPB;
}enum GirlFriend{XIAO_LI(20);private final int age;private GirlFriend(int age){this.age = age;}}

练习二

案例：颜色枚举类Color(使用enum声明)1、声明颜色枚举类：7个常量对象：RED, ORANGE, YELLOW, GREEN, CYAN, BLUE,PURPLE;2、在测试类中，使用枚举类，获取绿色对象，并打印对象。

package chapter08_oop3_teacher.src.com.atguigu10._enum.exer2;/*** ClassName: Color* Description:** @Author 尚硅谷-宋红康* @Create 15:12* @Version 1.0*/
public enum Color {RED, ORANGE, YELLOW, GREEN, CYAN, BLUE,PURPLE;
}

练习三

案例拓展：颜色枚举类(使用enum声明)
（1）声明颜色枚举类Color：- 声明final修饰的int类型的属性red,green,blue
- 声明final修饰的String类型的属性description
- 声明有参构造器Color(int red, int green, int blue,String description)
- 创建7个常量对象：红、橙、黄、绿、青、蓝、紫，
- 重写toString方法，例如：RED(255,0,0)->红色（2）在测试类中，使用枚举类，获取绿色对象，并打印对象。提示：
- 7个常量对象的RGB值如下：
红：(255,0,0)
橙：(255,128,0)
黄：(255,255,0)
绿：(0,255,0)
青：(0,255,255)
蓝：(0,0,255)
紫：(128,0,255)7个常量对象名如下：
RED, ORANGE, YELLOW, GREEN, CYAN, BLUE,PURPLE

package chapter08_oop3_teacher.src.com.atguigu10._enum.exer3;/*** ClassName: ColorTest* Description:** @Author 尚硅谷-宋红康* @Create 15:14* @Version 1.0*/
public class ColorTest {public static void main(String[] args) {System.out.println(Color.GREEN);}
}enum Color{RED(255,0,0,"红色"),ORANGE(255,128,0,"橙色"),YELLOW(255,255,0,"黄色"),GREEN(0,255,0,"绿色"),CYAN(0,255,255,"青色"),BLUE(0,0,255,"蓝色"),PURPLE(128,0,255,"紫色");private final int red;private final int green;private final int blue;private final String description;//颜色的描述Color(int red, int green, int blue, String description) {this.red = red;this.green = green;this.blue = blue;this.description = description;}public int getRed() {return red;}public int getGreen() {return green;}public int getBlue() {return blue;}public String getDescription() {return description;}@Overridepublic String toString() {
//        return name() + "(" + red + "," + green + "," + blue + ")->" + description;return super.toString() + "(" + red + "," + green + "," + blue + ")->" + description;}
}