if语句的数据驱动优化（Java版）

int num=2;

if (num==1){
    System.out.println("一");
}
else if (num==2){
    System.out.println("二");
}
else if (num==3){
    System.out.println("三");
}
else if (num==4){
    System.out.println("四");
}
else if (num==5){
    System.out.println("五");
}else {
    System.out.println("其它");
}

public static String ConvertNumber(int num){
    Map<Integer,String> map=new HashMap<Integer,String>();
    map.put(1,"一");
    map.put(2,"二");
    map.put(3,"三");
    map.put(4,"四");
    map.put(5,"五");
    for (Integer integer:map.keySet()){
        if (integer==num){
            return map.get(integer);
        }
    }
    return "其它";
}