定义枚举的构造函数，方法和字段

import org.junit.Test;

public class lan {
@Test
public void test(){
print(Grade.D);
}

public void print(Grade g) {
String valueString = g.getValue();
System.out.println(valueString);
}
}

enum Grade{
A("100-90"),B("89-80"),C("79-70"),D("69-60"),E("59-0");

private String value;
private Grade(String value){
this.value = value;
}

public String getValue(){
return this.value;
}
}