How to read from file to Set with objectInputStream

问题

I'm trying to read some information from a file with ObjectInputStream method. For some reason, the file does not contain the information after the command executed.

No error appears.

This is my code :

public boolean findUser(String user_id) throws Exception {          

    try (ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream(fILENAME))){
        //System.out.println("Adsfasdf");
        System.out.println(objectInputStream);
        Set<MarkoliaUser> users = (Set<MarkoliaUser>) objectInputStream.readObject();
        for(MarkoliaUser user : users)
            System.out.println(user.toString());
    }

    return true;
}

Please advise,

来源：https://stackoverflow.com/questions/62333962/how-to-read-from-file-to-set-with-objectinputstream