[Spring Data JPA] Custom ID is assigned in a unique sequence at the time of registration.

Introduction

When registering data with "Spring Data JPA" This is a summary of the codes when prefixes are added to the numbers assigned in the sequence.

environment

Java 8 PostgreSQL 10.5

What i did

Implement your own Generator. (Prefixer)

Inherits SequenceStyleGenerator. Numbering in the sequence uses the internal (superclass) processing as it is. The original Generator is the role of prefixing the numbered ones.

Describe Generator specification and parameters in Entity

Specify the sequence, prefix, and format in Entity. If you do not specify a sequence, it will try to use hibernate_sequence. (I was a little addicted here)

Source

The implemented source.

Original Generator

python

import java.io.Serializable;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.enhanced.SequenceStyleGenerator;
import org.hibernate.internal.util.config.ConfigurationHelper;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.type.LongType;
import org.hibernate.type.Type;

public class PrefixedIdGenerator extends SequenceStyleGenerator {

    public static final String VALUE_PREFIX_PARAMETER = "valuePrefix";
    public static final String VALUE_PREFIX_DEFAULT = "";
    private String valuePrefix;


    public static final String NUMBER_FORMAT_PARAMETER = "numberFormat";
    public static final String NUMBER_FORMAT_DEFAULT = "%d";

    private String numberFormat;

    @Override
    public Serializable generate(SharedSessionContractImplementor session, Object object) throws HibernateException {
        return valuePrefix + String.format(numberFormat, super.generate(session, object));
    }

    @Override
    public void configure(Type type, Properties params, ServiceRegistry serviceRegistry) throws MappingException {
        super.configure(LongType.INSTANCE, params, serviceRegistry);
        valuePrefix = ConfigurationHelper.getString(VALUE_PREFIX_PARAMETER, params, VALUE_PREFIX_DEFAULT);
        numberFormat = ConfigurationHelper.getString(NUMBER_FORMAT_PARAMETER, params, NUMBER_FORMAT_DEFAULT);
    }
}

Entity

python

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import lombok.Data;

import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Parameter;

@Entity
@Data
@Table(name = "trial")
public class Trial {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seq_trial")
    @GenericGenerator(
            name = "seq_trial",
            strategy = "PrefixedIdGenerator",
            parameters = {
                @Parameter(name = PrefixedIdGenerator.SEQUENCE_PARAM, value = "seq_trial"),
                @Parameter(name = PrefixedIdGenerator.VALUE_PREFIX_PARAMETER, value = "B_"),
                @Parameter(name = PrefixedIdGenerator.NUMBER_FORMAT_PARAMETER, value = "%05d") })
    @Column(name = "trial_id")
    private String trialId;

    @Column(name = "trial_name")
    private String trialName;
}

Service

python

@Service
public class TrialService {

    @Autowired
    private TrialRepository repository;

    @Transactional
    public void insert() {

        Trial entity = new Trial();
        entity.setTrialName("trial_xxxxxxxx");

        repository.save(entity);
    }
}

Runtime log

2019/05/24 17:54:18.505 [http-nio-8099-exec-1] DEBUG SqlStatementLogger 92 : 
    select
        nextval ('seq_test')
2019/05/24 17:54:22.313 [http-nio-8099-exec-1] DEBUG SqlStatementLogger 92 : 
    insert 
    into
        trial
        (trial_name, trial_id) 
    values
        (?, ?)
2019/05/24 17:54:22.318 [http-nio-8099-exec-1] TRACE BasicBinder 65 : binding parameter [1] as [VARCHAR] - [trial_xxxxxxxx]
2019/05/24 17:54:22.319 [http-nio-8099-exec-1] TRACE BasicBinder 65 : binding parameter [2] as [VARCHAR] - [B_00001]

Referenced site

How to Implement a Custom, Sequence-Based ID Generator

that's all