如何让唯一的用户ID不容易被猜到？

Question

I able to add users to room but users have number that is easy to guess. Can I have easy add users with not easy to guess id number?

Entity is

@Entity public class EntityUser {

    @PrimaryKey(autoGenerate = true)
    long userId;
    String userName;
}

Dao is

@Dao
public interface DaoUser {

    @Insert
    long insert(EntityUser entityUser);
}

Database is

@Database(entities = {EntityUser.class}, version = 1, exportSchema = false)
public abstract class UserDatabase extends RoomDatabase {

    abstract DaoUser daoUser();

}

I use

    userDatabase = Room.databaseBuilder(this,UserDatabase.class,"user.sqlite")
            .allowMainThreadQueries()
            .build();

    EntityUser user1 = new EntityUser();
    user1.userName = "Pandas";
    long user1id = userDatabase.daoUser().insert(user1);
    user1.userName = "Ellies";
    long user2id = userDatabase.daoUser().insert(user1);

I get 1 then 2.

I tried no autoGenerate but got Unique constraint error.

Answer 1

You can simply use UUID.

@Entity public class EntityUser {
    @PrimaryKey(autoGenerate = true)
    long userId;
    String objectId;
    String userName;
}

And then when you generate an object you can do it like this:

EntityUser user1 = new EntityUser();
user1.userName = "Pandas";
user1.objectId = UUID.randomUUID().toString();