Jpa @Converter get id of entity

Question

Problem

I need to hash user password on entity level (not on Controller level) and @Converter seems to be right choice, with JavaEE, no spring.

Show me the code

Here the code using Jpa AttributeConverter:

import java.nio.charset.StandardCharsets;

import javax.inject.Inject;
import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.hash.Hashing;

@Converter
public class JPACryptoConverter implements AttributeConverter<String, String> {

    private static Logger logger = LoggerFactory.getLogger(JPACryptoConverter.class);

    private String salt = "helloWorld";

    @Inject
    private UserRepository userRepository;

    @Override
    public String convertToDatabaseColumn(String sensitive) {
        return Hashing.sha512().hashString(salt + sensitive, StandardCharsets.UTF_8).toString();
    }

    @Override
    public String convertToEntityAttribute(String sensitive) {
        String tmp = Hashing.sha512().hashUnencodedChars(sensitive).toString();
        return tmp.substring(0, salt.length());
    }
}

I want to substitute salt string to entity defined salt on user table, but how to get this information ?

In order to get this information, I need to access userRepository using entity id and get salt, there is a way to find this information using @Converter ?

Note: I have tried with lifecycle listeners, preload, preupdate, prepersist, but because I'm using jpa Criteria, listeners are called after the query

Answer 1

I don't know exactly what you want, is that you want hash the user's pw before store into db? You create a converter and want to using it? something to do is add @Convert(converter = JPACryptoConverter.class)

@Entity
class UserEntity {

    @Column(name = "pw")
    @Convert(converter = JPACryptoConverter.class)
    private String pw;
}

And please remove @Converter from your JPACryptoConverter. It just:

public class JPACryptoConverter implements AttributeConverter<String, String>...

not:

@Converter
public class JPACryptoConverter implements AttributeConverter<String, String>...

//To using Strong pw hash 
public static String hash(String plainPassword) {
    if (StringUtils.isBlank(plainPassword)) {
        throw new EmptyPasswordException("Password could not be empty");
    }
    return BCrypt.hashpw(plainPassword, BCrypt.gensalt());
}

public static boolean checkPassword(String plainPassword, String hash) {
    return BCrypt.checkpw(plainPassword, hash);
}

Answer 2

If it`s for Authentication in SpringBoot then you should use a WebSecurityConfigurereAdapter and implement the configure method. and have something like this:

@Override
public void configure(AuthenticationManagerBuilder auth) throws Exception {
    auth.userDetailsService(userDetailsServiceImpl).passwordEncoder(passwordEncoder());
}

private PasswordEncoder passwordEncoder() {

    return new PasswordEncoder() {
        @Override
        public String encode(CharSequence charSequence) {
            return charSequence.toString();
        }

        @Override
        public boolean matches(CharSequence charSequence, String s) {
            return charSequence.toString().equals(s);
        }
    };
}