如何获得正确的DatabaseReference

我正在创建一个用户配置文件,但我不知道如何获取子节点并将其显示在用户配置文件中,如何正确引用?如果有任何意见或建议,我将不胜感激,提前感谢!!

用户配置文件

private void showUserProfile( FirebaseUser firebaseUser) {

String userID = firebaseUser.getUid();

DatabaseReference referenceProfile = FirebaseDatabase.getInstance().getReference("Users"); 
// 👆
referenceProfile.child(userID).addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot snapshot) {
        ReadWriteUserDetails readUserDetail = snapshot.getValue(ReadWriteUserDetails.class);
        if(readUserDetail != null){
            fullname = firebaseUser.getDisplayName();
            email = firebaseUser.getEmail();
            doB = readUserDetail.birthday;
            discount = readUserDetail.discount;

            textViewFullName.setText(fullname);
            textViewEmail.setText(email);
            textViewDoB.setText(doB);
            textViewDiscount.setText(discount);
        }
    }

Firebase

ReadWriteUserDetail类

public class ReadWriteUserDetails {
    public String birthday, discount;

    public ReadWriteUserDetails(){};

    public ReadWriteUserDetails(String textBirthday, String textDiscount){
        this.birthday = textBirthday;
        this.discount = textDiscount;
    }
}