Lazy Initialized object loading without retrieval using Spring hibernation

Question

Schooldto

@Id @Column(name = "c_sm_npk_id", nullable = false) @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "school_sequence") @SequenceGenerator(name = "school_sequence", sequenceName = "t_school_master_c_sm_npk_id_seq", initialValue = 1, allocationSize = 1) private Long id; @Column(name="c_sm_vnm_name") private String name; @ManyToOne(cascade = {CascadeType.MERGE},fetch=FetchType.LAZY) UserDto owner; /*Many other fileds omit for simplicity with getter/setter methods*/ 

Userdto

 public class UserDto implements Serializable { private static final long serialVersionUID = 1L; public UserDto() { } @Id @Column(name = "c_um_npk_id", nullable = false) @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_sequence") @SequenceGenerator(name = "user_sequence", sequenceName = "t_user_master_c_um_npk_id_seq", initialValue = 1, allocationSize = 1) private Long id; @Column(name = "c_um_vnm_username", nullable = false) private String username; @Column(name = "c_um_vnm_email_address") private String emailId; @JsonSerialize(using = JsonDateSerializer.class) @Column(name = "c_um_dnm_birth_date",nullable=false) @Temporal(TemporalType.DATE) private Date birthdate; @Column(name="c_um_nnm_age",nullable=false) private int age; @Column(name = "c_um_vnm_first_name") private String firstName; @Column(name = "c_um_vnm_last_name") private String lastName; @Column(name = "c_um_vnm_mobile_number") private String mobileNumber; @Column(name = "c_um_vnm_gender") private String gender; @JsonManagedReference("user-role") @OneToMany(mappedBy = "userDto", cascade = CascadeType.ALL, fetch = FetchType.LAZY) private List<RoleDto> roleDtos; /* getter setter of properties */ } 

Here I defined the owner as the Lazy collection. but when I try to find all schools as below:

 public List<SchoolDto> getAllSchoolsWithAdvanceSearch(SchoolSearchDto schoolSearchDto) { return getEntityManager().createQuery("SELECT s from SchoolDto s").setFirstResult(schoolSearchDto.getFrom()).setMaxResults(schoolSearchDto.getSize()).getResultList(); } 

this list of returns to schools with all the information about its owner, including the role of the owner (which again is the Lazy collection form UserDto), when I register a request for sleep mode, I get only one choice, as shown below:

 select schooldto0_.c_sm_npk_id as c1_24_, schooldto0_.c_sm_vnm_address_line_1 as c2_24_, schooldto0_.owner_c_um_npk_id as owner17_24_ from t_school_master schooldto0_ 

during the search, I am faced with the fact that this may be a problem with Jackson serialization, so I made the changes below according to jackson - do not serialize lazy objects and Avoid serializing Jackson on unattractive lazy objects , as shown below

servlet.xml applications

  <mvc:annotation-driven> <mvc:message-converters> <ref bean="jsonHttpMessageConverter"/> </mvc:message-converters> </mvc:annotation-driven> <bean id="jsonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"> <property name="objectMapper"> <bean class="com.util.HibernateAwareObjectMapper" /> </property> </bean> 

HibernateAwareObjectMapper.java

 public HibernateAwareObjectMapper() { this.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); Hibernate4Module module = new Hibernate4Module(); module.configure(Hibernate4Module.Feature.FORCE_LAZY_LOADING, false); module.disable(Hibernate4Module.Feature.USE_TRANSIENT_ANNOTATION); registerModule(module); } 

Note. I need owner information later, so I cannot mark it as @JsonIgnore .

Please help me solve this problem. thanks in advance

Edit: current output

 0: { "id": 1 "name": "school1" "address1": null owner : { "id" : 1, "firstName": "Rutesha", "lastName" : "Patel", "roles":[{ "name" : "SCHOOL_ADMIN" }] } } 

Edit: Expected Result

 0: { "id": 1 "name": "school1" "address1": null } OR 0: { "id": 1 "name": "school1" "address1": null owner : null } 

Answer 1

Make the following changes

 return getEntityManager().createQuery("SELECT s.id,s.name,s.address1 from SchoolDto s").setFirstResult(schoolSearchDto.getFrom()).setMaxResults(schoolSearchDto.getS‌​ize()).getResultList(); 

@ManyToOne - similar annotations have in the documentation for the same issue, but in this case it is much more likely that the JPA provider will consider the FetchType hint.

 @ManyToOne(cascade={CascadeType.MERGE},optional = false,fetch=FetchType.LAZY ) UserDto owner; 

The following annotations may also help.

 @OneToMany(fetch = FetchType.LAZY, mappedBy = "owner") @Cascade(CascadeType.ALL) @Fetch(FetchMode.SELECT) @BatchSize(size = 10) 

Perhaps you should use @JoinColumn(name="other_entity_fk") .

Example

 @ManyToOne(fetch = FetchType.LAZY) @Fetch(FetchMode.SUBSELECT) @JoinColumn(name = "STOCK_ID", nullable = false) public Stock getStock() { return this.stock; } 

Link Strategies for Fetch Mode