switch

char grade = 'C';

String info = "";
switch (grade)
{
    case 'A':
        info = "优秀";
        break;
    case 'B':
        info = "良好";
    case 'C':
        info = "及格";
        break;
    case 'D':
        info = "你需要再努力努力";
        break;
    default:
        info = "未知等级";
}
System.out.println(info + "：你的等级是： " + grade);