Finding an entity

To find an entity, EntityManger interface provides find() method that searches an element on the basis of primary key.

JPA Entity Finding Example

Here, we will search a particular record and fetch it on the console.

This example contains the following steps: -

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

StudentEntity.java

package com.javatpoint.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.javatpoint.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 FindStudent.java under com.javatpoint.jpa.find package to persist the entity object with data.

FindStudent.java

package com.javatpoint.jpa.find;

import javax.persistence.*;

import com.javatpoint.jpa.student.*;

public class FindStudent {
	public static void main(String args[])
	{
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("Student_details");
		EntityManager em=emf.createEntityManager();
		
	
		
		StudentEntity s=em.find(StudentEntity.class,101);
		
		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: