JPA Updating an Entity

by Online Tutorials Library July 14, 2022

Update an Entity

JPA allows us to change the records in database by updating an entity.

JPA Entity Update Example

Here, we will update the age of a student on the basis of primary key.

This example contains the following steps: –

Create an entity class named as StudentEntity.java under com.tutoraspire.jpa.student package that contains attributes s_id, s_name and s_age.

StudentEntity.java

  package com.tutoraspire.jpa.student;  import javax.persistence.*;    @Entity  @Table(name=”student”)  public class StudentEntity {    @Id  private int s_id;  private String s_name;  private int s_age;    public StudentEntity(int s_id, String s_name, int s_age) {  super();  this.s_id = s_id;  this.s_name = s_name;  this.s_age = s_age;  }    public StudentEntity() {  super();  }    public int getS_id() {  return s_id;  }    public void setS_id(int s_id) {  this.s_id = s_id;  }    public String getS_name() {  return s_name;  }    public void setS_name(String s_name) {  this.s_name = s_name;  }    public int getS_age() {  return s_age;  }    public void setS_age(int s_age) {  this.s_age = s_age;  }    }  

Now, map the entity class and other databases confiuguration in Persistence.xml file.

Persistence.xml

  <persistence>  <persistence-unit name=”Student_details”>    <class>com.tutoraspire.jpa.student.StudentEntity</class>    <properties>  <property name=”javax.persistence.jdbc.driver” value=”com.mysql.jdbc.Driver”/>  <property name=”javax.persistence.jdbc.url” value=”jdbc:mysql://localhost:3306/studentdata”/>  <property name=”javax.persistence.jdbc.user” value=”root”/>  <property name=”javax.persistence.jdbc.password” value=””/>  <property name=”eclipselink.logging.level” value=”SEVERE”/>  <property name=”eclipselink.ddl-generation” value=”create-or-extend-tables”/>  </properties>    </persistence-unit>  </persistence>  

Create a persistence class named as UpdateStudent.java under com.tutoraspire.jpa.update package to persist the entity object with data.

UpdateStudent.java

  package com.tutoraspire.jpa.update;  import javax.persistence.*;    import com.tutoraspire.jpa.student.*;  public class UpdateStudent {    public static void main(String args[])  {  EntityManagerFactory emf=Persistence.createEntityManagerFactory(“Student_details”);  EntityManager em=emf.createEntityManager();        StudentEntity s=em.find(StudentEntity.class,102);  System.out.println(“Before Updation”);  System.out.println(“Student id = “+s.getS_id());  System.out.println(“Student Name = “+s.getS_name());  System.out.println(“Student Age = “+s.getS_age());    s.setS_age(30);    System.out.println(“After Updation”);  System.out.println(“Student id = “+s.getS_id());  System.out.println(“Student Name = “+s.getS_name());  System.out.println(“Student Age = “+s.getS_age());      }    }  

Output:

JPA Update an Entity

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