再运行一下 ，default 后面最好加break 

	public class HelloWorld {
	    public static void main(String[] args) {
	        char today='日';
	        switch (today){
	            case'一':
	            case'三':
	            case'五':
	                System.out.println("吃包子");
	                break;
	            case'二':
	            case'四':
	            case'六':
	                System.out.println("吃油条");
	                break;
	            default:
	                System.out.println("吃主席套餐");
	        }
	    }
	}