多重if语句的简洁表达

public class HelloWorld {
public static void main(String[] args) {
int age=25;

    String a;
    if (age>60)
    a="老年";
    else if (age>40)
    a="中年";
    else if (age>18)
    a="少年";
    else 
    a="童年";

    System.out.println(a);
}

}