Spring Boot With H2 Database

 h2 database spring boot

For explanation watch video:

Directory Structure

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>2.6.6</version>

<relativePath/> <!-- lookup parent from repository -->

</parent>

<groupId>com.app</groupId>

<artifactId>SpringBootH2DB</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>SpringBootH2DB</name>

<description>Demo project for Spring Boot</description>

<properties>

<java.version>11</java.version>

</properties>

<dependencies>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId>

</dependency>

<dependency>

<groupId>com.h2database</groupId>

<artifactId>h2</artifactId>

<scope>runtime</scope>

</dependency>

<dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

<optional>true</optional>

</dependency>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-test</artifactId>

<scope>test</scope>

</dependency>

</dependencies>

<build>

<plugins>

<plugin>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

<configuration>

<excludes>

<exclude>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

</exclude>

</excludes>

</configuration>

</plugin>

</plugins>

</build>

</project>

application.properties

#server port

server.port=3031

spring.h2.console.enabled=true

spring.jpa.show-sql=true

spring.datasource.url=jdbc:h2:mem:testdb

#http://localhost:3031/h2-console

SpringBootH2DbApplication 

package com.app;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class SpringBootH2DbApplication {

public static void main(String[] args) {

SpringApplication.run(SpringBootH2DbApplication.class, args);

}

}

Employee

package com.app.entity;

import javax.persistence.CollectionTable;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.Table;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

@Data

@AllArgsConstructor

@NoArgsConstructor

@Entity

@Table(name = "emptab")

public class Employee {

@Id

@GeneratedValue

@Column(name = "eid")

private Integer empId;

@Column(name = "ename")

private String empName;

@Column(name = "esal")

private Double empSal;

private String dept;

public Employee(String empName, Double empSal, String dept) {

super();

this.empName = empName;

this.empSal = empSal;

this.dept = dept;

}

}

EmployeeRepository 

package com.app.repo;

import org.springframework.data.jpa.repository.JpaRepository;

import com.app.entity.Employee;

public interface EmployeeRepository extends JpaRepository<Employee, Integer>{

}

TestRunner 

package com.app.runner;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.CommandLineRunner;

import org.springframework.stereotype.Component;

import com.app.entity.Employee;

import com.app.repo.EmployeeRepository;

@Component

public class TestRunner implements CommandLineRunner{

@Autowired

private EmployeeRepository repo;

@Override

public void run(String... args) throws Exception {

//save the data

repo.save(new Employee("SAM",5000.0,"DEV"));

repo.save(new Employee("BROCK",6000.0,"QA"));

repo.save(new Employee("ANGELA",7000.0,"BA"));

repo.save(new Employee("Carla",8000.0,"DEV"));

repo.save(new Employee("Ram",9000.0,"QA"));

repo.save(new Employee("Shyam",10000.0,"BA"));

repo.save(new Employee("Raja",11000.0,"DEV"));

repo.save(new Employee("Rani",12000.0,"QA"));

repo.save(new Employee("Ramesh",13000.0,"BA"));

repo.save(new Employee("Sai",14000.0,"DEV"));

//print data

//repo.findAll().forEach(System.out::println);

System.out.println(repo.findById(3));

}

}