Java之多例设计

package Demo_1_25_多例设计;

public class Color {    //描述颜色的类
    private static final Color RED = new Color("红色");
    private static final Color GREEN = new Color("绿色");
    private static final Color BLUE = new Color("蓝色");
    private String title;
    private Color(String title) {   // 构造方法私有化
        this.title = title;
    }
    public static Color getInstance(String color){
        switch (color) {
            case "red":
                return RED;
            case "green":
                return GREEN;
            case "blue":
                return BLUE;
            default:
                return null;
        }
    }
    public String toString() {
        return this.title;
    }

}

package Demo_1_25_多例设计;

public class Main {
    public static void main(String[] args) {
        Color color = Color.getInstance("red");
        System.out.println(color);
    }
}