Spring data jpa: existsById: Check entity exists with this id or not

CrudRepository interface provides 'existsById' method, it is used to check whether an entity with given id exists or not.

boolean existsById(ID id)

Return true if an entity with the given id exists, false otherwise.

Example

Employee emp1 = Employee.builder().firstName("Ram").lastName("Gurram").build();

Employee persistedEmployee = employeeRepository.save(emp1);

boolean exist = employeeRepository.existsById(persistedEmployee.getId());

if (!exist) {
    System.out.println("Employee is not exist for given id");
} else {
    printEmployee(employeeRepository.findById(persistedEmployee.getId()).get());
}

Find the below working application.

Step 1: Create model class Employee.

Employee.java

package com.sample.app.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "employee")
public class Employee {
 @Id
 @GeneratedValue(strategy = GenerationType.AUTO)
 @Column(name = "employee_id")
 private int id;
 
 @Column(name = "first_name")
 private String firstName;
 
 @Column(name = "last_name")
 private String lastName;

 public int getId() {
  return id;
 }

 public void setId(int id) {
  this.id = id;
 }

 public String getFirstName() {
  return firstName;
 }

 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }

 public String getLastName() {
  return lastName;
 }

 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

 public static EmployeeBuilder builder() {
  return new EmployeeBuilder();
 }

 public static class EmployeeBuilder {
  private Employee emp;

  public EmployeeBuilder() {
   emp = new Employee();
  }

  public EmployeeBuilder firstName(String firstName) {
   emp.setFirstName(firstName);
   return this;
  }

  public EmployeeBuilder lastName(String lastName) {
   emp.setLastName(lastName);
   return this;
  }

  public Employee build() {
   return emp;
  }
 }

 @Override
 public String toString() {
  return "Employee [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + "]";
 }

}

Step 2: Create EmployeeRepository interface like below.

EmployeeRepository.java

package com.sample.app.repository;

import org.springframework.data.repository.CrudRepository;

import com.sample.app.model.Employee;  

public interface EmployeeRepository extends CrudRepository<Employee, Integer> {

 
}

Step 3: Create ‘application.properties’ file under src/main/resources.

application.properties

logging.level.root=WARN
logging.level.org.hibernate=ERROR

## H2 specific properties
spring.h2.console.enabled=true
spring.h2.console.path=/h2

spring.datasource.url=jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;

spring.datasource.username=krishna
spring.datasource.password=password123

spring.datasource.driverClassName=org.h2.Driver

## JPA specific properties
# Creates the schema, destroying previous data.
spring.jpa.hibernate.ddl-auto=create

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

## Database connection pooling properties
# Number of ms to wait before throwing an exception if no connection is available.
spring.datasource.max-wait=10000

# Maximum number of active connections that can be allocated from this pool at the same time.
spring.datasource.tomcat.max-active=10
spring.datasource.tomcat.max-idle=5
spring.datasource.tomcat.min-idle=3

Step 4: Define App.java class like below.

App.java    

package com.sample.app;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

import com.sample.app.model.Employee;
import com.sample.app.repository.EmployeeRepository;

@SpringBootApplication
public class App {

    private static void printEmployee(Employee emp) {
        System.out.println("------------------------------");
        System.out.println("Id : " + emp.getId());
        System.out.println("firstName : " + emp.getFirstName());
        System.out.println("lastName : " + emp.getLastName());
        System.out.println("------------------------------");
    }

    public static void main(String args[]) {
        SpringApplication.run(App.class, args);
    }

    @Bean
    public CommandLineRunner demo(EmployeeRepository employeeRepository) {
        return (args) -> {
            Employee emp1 = Employee.builder().firstName("Ram").lastName("Gurram").build();

            Employee persistedEmployee = employeeRepository.save(emp1);

            boolean exist = employeeRepository.existsById(persistedEmployee.getId());

            if (!exist) {
                System.out.println("Employee is not exist for given id");
            } else {
                printEmployee(employeeRepository.findById(persistedEmployee.getId()).get());
            }

        };
    }

}

Complete project structure looks like below.

Run App.java, you can able to see below messages in console.

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.6.RELEASE)

Hibernate: 
    
    drop table employee if exists
Hibernate: 
    
    drop sequence if exists hibernate_sequence
Hibernate: create sequence hibernate_sequence start with 1 increment by 1
Hibernate: 
    
    create table employee (
       employee_id integer not null,
        first_name varchar(255),
        last_name varchar(255),
        primary key (employee_id)
    )
Hibernate: 
    call next value for hibernate_sequence
Hibernate: 
    insert 
    into
        employee
        (first_name, last_name, employee_id) 
    values
        (?, ?, ?)
Hibernate: 
    select
        count(*) as col_0_0_ 
    from
        employee employee0_ 
    where
        employee0_.employee_id=?
Hibernate: 
    select
        employee0_.employee_id as employee1_0_0_,
        employee0_.first_name as first_na2_0_0_,
        employee0_.last_name as last_nam3_0_0_ 
    from
        employee employee0_ 
    where
        employee0_.employee_id=?
------------------------------
Id : 1
firstName : Ram
lastName : Gurram
------------------------------

You can download complete working application from this link.

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