我有以下两个域对象 Suggestion 和 UserProfile
它们以一对多的关系相互映射。当我使用 Spring Data JPA 获取所有建议时,我会使用每个建议对象获得相应的用户对象。即使我将 fetch
设置为 FetchType.Lazy
,也会观察到这个结果。以下是我的代码:
Suggestion.java
@Entity
@Table(name="suggestion")
@JsonIgnoreProperties({"suggestionLikes"})
public class Suggestion {
public Suggestion() {
// TODO Auto-generated constructor stub
}
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="suggestion_id")
private Integer suggestionId;
@Column(name="description")
private String description;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name="suggestion_by")
private UserProfile user;
//getters and setters
}
UserProfile.java
@Entity
@Table(name = "user_master")
@JsonIgnoreProperties({"suggestions", "suggestionLikes"})
public class UserProfile implements Serializable {
/**
*
*/
private static final long serialVersionUID = 7400472171878370L;
public UserProfile() {
}
@Id
@NotNull
@Column(name = "username", length = 55)
private String userName;
@NotNull
@Column(name = "password")
private String password;
@OneToMany(mappedBy = "user", fetch = FetchType.LAZY)
private Set<Suggestion> suggestions;
//getters and setters
}
以下是获取记录的 服务 :
@Override
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public List<Suggestion> getAllSuggestion() {
return suggestionRespository.findAll();;
}
建议库:
@Repository
public interface SuggestionRespository extends JpaRepository<Suggestion,
Integer> {
public List<Suggestion> findAll();
}
以下是 应用程序 类:
@EnableTransactionManagement
@SpringBootApplication
public class AngularSpringbootApplication {
public static void main(String[] args) {
SpringApplication.run(AngularSpringbootApplication.class, args);
}
}
application.properties:
spring.datasource.url=jdbc:mysql://localhost:3306/plan_trip
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.properties.hibernate.dialect =
org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto = update
spring.jackson.serialization.fail-on-empty-beans=false
执行
getAllSuggestions()
时收到的响应:[
{
"suggestionId": 2,
"description": "Germanyi!",
"createdBy": "vinit2",
"createdDate": "2018-06-19T10:38:32.000+0000",
"modifiedBy": "vinit2",
"modifiedDate": "2018-06-19T10:38:32.000+0000",
"user": {
"userName": "vinit2",
"password":
"$2a$10$.hP0sQWpl6qqDKiNTkiu0OciQeHRFnkEbEWcDvnv1HY4QCi2tKo.2",
"firstName": "Vinit2",
"lastName": "Divekar2",
"emailAddress": "[email protected]",
"createdBy": null,
"modifedBy": null,
"createdDate": "2018-06-04",
"modifiedDate": "2018-06-04",
"isActive": "1",
"handler": {},
"hibernateLazyInitializer": {}
}
},
{
"suggestionId": 1,
"description": "Vasai!",
"createdBy": "vinit1",
"createdDate": "2018-06-19T10:37:38.000+0000",
"modifiedBy": "vinit1",
"modifiedDate": "2018-06-19T10:37:38.000+0000",
"user": {
"userName": "vinit1",
"password": "$2a$10$D0RMSTWu03Jw7wC1/zqFxOOjb0Do24o/4mq2PhDhRUyBrs8bdGvUG",
"firstName": "Vinit1",
"lastName": "Divekar1",
"emailAddress": "[email protected]",
"createdBy": null,
"modifedBy": null,
"createdDate": "2018-06-04",
"modifiedDate": "2018-06-04",
"isActive": "1",
"handler": {},
"hibernateLazyInitializer": {}
}
}
]
预期回应:
[{
"suggestionId": 2,
"description": "Germanyi!",
"createdBy": "vinit2",
"createdDate": "2018-06-19T10:38:32.000+0000",
"modifiedBy": "vinit2",
"modifiedDate": "2018-06-19T10:38:32.000+0000"
},
{
"suggestionId": 1,
"description": "Vasai!",
"createdBy": "vinit1",
"createdDate": "2018-06-19T10:37:38.000+0000",
"modifiedBy": "vinit1",
"modifiedDate": "2018-06-19T10:37:38.000+0000"
}
]
当我将
FetchType
声明为 Lazy
时,当我在 Suggestion 实体上执行 findAll()
时,我不应该获得 User 对象(以 JSON 格式)。我在这里缺少什么?
最佳答案
您可以使用 @JsonManagedReference & @JsonBackReference 来防止 jakson 进行代理调用。以下代码可能对您有所帮助。
@JsonBackReference
@OneToMany(mappedBy = "user", fetch = FetchType.LAZY)
private Set<Suggestion> suggestions;
@JsonManagedReference
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "suggestion_by")
private UserProfile user;
添加以下依赖项,根据您的 hibernate 状态更改版本
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-hibernate5</artifactId>
</dependency>
最后添加一个新配置
@Configuration
public class JacksonConfig {
@Bean
public Jackson2ObjectMapperBuilderCustomizer addCustomBigDecimalDeserialization() {
return new Jackson2ObjectMapperBuilderCustomizer() {
@Override
public void customize(Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder) {
jacksonObjectMapperBuilder.featuresToDisable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
jacksonObjectMapperBuilder.modules(new Hibernate5Module());
}
};
}
}