Java – unable to get JPA entity ID in JSON output

We are trying to use the POC of spring data JPA and spring data rest

We are using a simple entity that extends abstractpersistent (which is a spring data JPA class) http://docs.spring.io/spring-data/jpa/docs/current/api/org/springframework/data/jpa/domain/AbstractPersistable.html ).

This is the source code of this one:

@MappedSuperclass
public abstract class AbstractPersistable<PK extends Serializable> implements Persistable<PK> {

    private static final long serialVersionUID = -5554308939380869754L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "ID")
    private PK id;

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Persistable#getId()
     */
    public PK getId() {

        return id;
    }

    /**
     * Sets the id of the entity.
     * 
     * @param id the id to set
     */
    protected void setId(final PK id) {

        this.id = id;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Persistable#isNew()
     */
    public boolean isNew() {

        return null == getId();
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {

        return String.format("Entity of type %s with id: %s",this.getClass().getName(),getId());
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {

        if (null == obj) {
            return false;
        }

        if (this == obj) {
            return true;
        }

        if (!getClass().equals(obj.getClass())) {
            return false;
        }

        AbstractPersistable<?> that = (AbstractPersistable<?>) obj;

        return null == this.getId() ? false : this.getId().equals(that.getId());
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {

        int hashCode = 17;

        hashCode += null == getId() ? 0 : getId().hashCode() * 31;

        return hashCode;
    }
}

And our entities:

@Entity
@Table(name = "TEST_ENTITY")
public class TestEntity extends AbstractPersistable<Long> {

    @Column(name = "TITLE",nullable = false,length = 100)
    private String title;

    @Column(name = "DESCRIPTION",length = 500)
    private String description;

    @ManyToOne(fetch = FetchType.LAZY,optional = false)
    @JoinColumn(name = "GLOBAL_DATATYPE_ID",referencedColumnName = "ID",updatable = false)
    private globalDataType dataType;

    @Enumerated(EnumType.STRING)
    @Column(name = "VALUE_TYPE",length = 30)
    private ValueType valueType;

    @Enumerated(EnumType.STRING)
    @Column(name = "ATTRIBUTE_TYPE",length = 30)
    private AttributeType attributeType;

    @Column(name = "FE_DISPLAY")
    @Convert(converter=BooleanTFConverter.class)
    private Boolean feDisplay;

 {... getter setter equals hashcode toString ...}
}

Then the service (using spring data rest):

@RepositoryRestResource(path = "test")
public interface TestEntityRepository extends JpaRepository<TestEntity,Long> {
}

We use spring to launch and run the application. The output on chrome (URL: http: / / localhost: 8080 / test) is JSON Hal data (ID!!!):

{
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/test{?page,size,sort}","templated" : true
    }
  },"_embedded" : {
    "testEntities" : [ {
      "title" : "Test","description" : "TEST","valueType" : "SINGLE","attributeType" : "ATTRIBUTE","feDisplay" : true,"new" : false,"_links" : {
        "self" : {
          "href" : "http://localhost:8080/test/1"
        },"dataType" : {
          "href" : "http://localhost:8080/test/1/dataType"
        }
      }
    } ]
  },"page" : {
    "size" : 20,"totalElements" : 1,"totalPages" : 1,"number" : 0
  }
}

The other thing is when we're in testentity（ http://docs.spring.io/spring-data/jpa/docs/current/api/org/springframework/data/jpa/domain/AbstractAuditable.html ）When abstractauditable is used on, it works. We get the field value from abstractauditable, but we still don't get the id

@Entity
@Table(name = "TEST_ENTITY")
public class TestEntity  extends AbstractAuditable<User,Long> {
...
}

@MappedSuperclass
public abstract class AbstractAuditable<U,PK extends Serializable> extends AbstractPersistable<PK> implements
        Auditable<U,PK> {

    private static final long serialVersionUID = 141481953116476081L;

    @ManyToOne(fetch = FetchType.LAZY,optional = false)
    @JoinColumn(name = "CREATED_BY",updatable = false)
    private U createdBy;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "CREATED_DATE")
    private Date createdDate;

    @ManyToOne(fetch = FetchType.LAZY,optional = false)
    @JoinColumn(name = "LAST_MODIFIED_BY",updatable = false)
    private U lastModifiedBy;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "LAST_MODIFIED_DATE")
    private Date lastModifiedDate;

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Auditable#getCreatedBy()
     */
    public U getCreatedBy() {

        return createdBy;
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.springframework.data.domain.Auditable#setCreatedBy(java.lang.Object)
     */
    public void setCreatedBy(final U createdBy) {

        this.createdBy = createdBy;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Auditable#getCreatedDate()
     */
    public DateTime getCreatedDate() {

        return null == createdDate ? null : new DateTime(createdDate);
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.springframework.data.domain.Auditable#setCreatedDate(org.joda.time
     * .DateTime)
     */
    public void setCreatedDate(final DateTime createdDate) {

        this.createdDate = null == createdDate ? null : createdDate.toDate();
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Auditable#getLastModifiedBy()
     */
    public U getLastModifiedBy() {

        return lastModifiedBy;
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.springframework.data.domain.Auditable#setLastModifiedBy(java.lang
     * .Object)
     */
    public void setLastModifiedBy(final U lastModifiedBy) {

        this.lastModifiedBy = lastModifiedBy;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Auditable#getLastModifiedDate()
     */
    public DateTime getLastModifiedDate() {

        return null == lastModifiedDate ? null : new DateTime(lastModifiedDate);
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.springframework.data.domain.Auditable#setLastModifiedDate(org.joda
     * .time.DateTime)
     */
    public void setLastModifiedDate(final DateTime lastModifiedDate) {

        this.lastModifiedDate = null == lastModifiedDate ? null : lastModifiedDate.toDate();
    }
}

JSON Hal results:

{
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/test{?page,"_embedded" : {
    "testEntities" : [ {
      "createdBy" : {
        "username" : "xxx.admin"
      },"createdDate" : {
        "year" : 2014,"era" : 1,"dayOfYear" : 282,"dayOfWeek" : 4,"dayOfMonth" : 9,"weekOfWeekyear" : 41,"monthOfYear" : 10,"yearOfEra" : 2014,"yearOfCentury" : 14,"centuryOfEra" : 20,"weekyear" : 2014,"millisOfSecond" : 0,"millisOfDay" : 65724000,"secondOfMinute" : 24,"secondOfDay" : 65724,"minuteOfHour" : 15,"minuteOfDay" : 1095,"hourOfDay" : 18,"chronology" : {
          "zone" : {
            "fixed" : false,"uncachedZone" : {
              "cachable" : true,"fixed" : false,"id" : "Europe/London"
            },"id" : "Europe/London"
          }
        },"zone" : {
          "fixed" : false,"uncachedZone" : {
            "cachable" : true,"id" : "Europe/London"
          },"id" : "Europe/London"
        },"millis" : 1412874924000,"afterNow" : false,"beforeNow" : true,"equalNow" : false
      },"lastModifiedBy" : null,"lastModifiedDate" : {
        "year" : 2014,"millisOfDay" : 65731000,"secondOfMinute" : 31,"secondOfDay" : 65731,"millis" : 1412874931000,"title" : "Test","number" : 0
  }
}

Editing: Solutions

Add custom repositoryrestmvcconfiguration

@Configuration
public class MyRepositoryRestMvcConfiguration extends RepositoryRestMvcConfiguration {

    protected void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        config.exposeIdsFor(TestEntity.class);
    }
}

Then change @ import in your application Java configuration class

Before:

@Configuration
@EnableTransactionManagement
@Import(RepositoryRestMvcConfiguration.class)
@EnableJpaRepositories(basePackages="uk.co.xxx.marketplace.data.repository")
@PropertySources({@PropertySource("classpath:hibernate.properties"),@PropertySource("classpath:persistence.properties")})
@ComponentScan(value = "uk.co.xxx.marketplace.data")
@EnableAutoConfiguration
public class Application {
...
}

actual:

@Configuration
@EnableTransactionManagement
@Import(MyRepositoryRestMvcConfiguration.class)
@EnableJpaRepositories(basePackages="uk.co.xxx.marketplace.data.repository")
@PropertySources({@PropertySource("classpath:hibernate.properties"),@PropertySource("classpath:persistence.properties")})
@ComponentScan(value = "uk.co.xxx.marketplace.data")
@EnableAutoConfiguration
public class Application {
...
}

Solution

You can inherit the class repositoryrestconfiguration (or repositoryrestmvcconfiguration, if spring MVC is used), and call the method exposeidsfor () with the domain class you want to expose the ID