Understanding @PreUpdate and @PrePersist in Hibernate/JPA with Java Session

Introduction

In Hibernate/JPA, @PreUpdate and @PrePersist are two annotations that are used to execute custom code before an entity is updated or persisted respectively. These annotations are useful when we need to perform certain operations before the actual update or persist operation takes place. In this article, we will discuss @PreUpdate and @PrePersist in Hibernate/JPA with Java Session.

@PreUpdate

@PreUpdate annotation is used to execute custom code before an entity is updated. This annotation is applied to a method in an entity class and the method is executed before the entity is updated. The method should have void return type and should take no arguments.

@Entity
@Table(name = "employee")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    @PreUpdate
    public void beforeUpdate() {
        // custom code to be executed before update
    }
}

In the above example, the method "beforeUpdate" is executed before the entity is updated. We can use this method to perform any custom operations before the update.

@PrePersist

@PrePersist annotation is used to execute custom code before an entity is persisted. This annotation is also applied to a method in an entity class and the method is executed before the entity is persisted. The method should have void return type and should take no arguments.

@Entity
@Table(name = "employee")
public class Employee {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    @PrePersist
    public void beforePersist() {
        // custom code to be executed before persist
    }
}

In the above example, the method "beforePersist" is executed before the entity is persisted. We can use this method to perform any custom operations before the persist.

Conclusion

@PreUpdate and @PrePersist annotations are two useful annotations in Hibernate/JPA that allow us to execute custom code before an entity is updated or persisted respectively. These annotations are applied to a method in an entity class and the method is executed before the actual update or persist operation takes place. We can use these annotations to perform any custom operations before the update or persist.