如果你只是觉得 if 有点多，给你提供一个思路，你看是否可行

public static void main(String[] args){
String officeCode = null;
if(Objects.nonNull(officeCode = a()) || Objects.nonNull(officeCode = b())|| Objects.nonNull(officeCode = c())){
}else{
officeCode = "default value";
}
System.out.println("officeCode:"+officeCode);
}

private static String c(){
System.out.println("C");
return "C";
}
private static String b(){
System.out.println("B");
return "B";
}

private static String a(){
System.out.println("A");
return null;
}