SPRING BOOT JPA EXAMPLE - saravanagumar’s blog

This tutorial guides you through on building simple REST APIs using Spring Data JPA and Spring Boot. 

At the end of this tutorial, you would be able to write the applications with Spring Data JPA using Spring Boot

Declare spring-boot-starter-data-jpa, it grabs Spring Data,Hibernate and JPA related stuff.  

pom.xml

<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
  http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mkyong</groupId>
    <artifactId>spring-boot-jpa-oracle-example</artifactId>
    <packaging>jar</packaging>
    <version>1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.1.RELEASE</version>
    </parent>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <!-- Spring data JPA, default tomcat pool, exclude it -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.tomcat</groupId>
                    <artifactId>tomcat-jdbc</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- Oracle JDBC driver -->
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc7</artifactId>
            <version>12.1.0</version>
        </dependency>

        <!-- HikariCP connection pool -->
        <dependency>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
            <version>2.6.0</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <!-- Package as an executable jar/war -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

        </plugins>
    </build>

</project>

Java Persistence API – JPA

Customer Model. Add JPA annotations, and use “sequence ” to generate the auto increase primary ID.

Customer.java
package com.mkyong.model;

import javax.persistence.*;
import java.util.Date;

@Entity
public class Customer {

	// "customer_seq" is Oracle sequence name.
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CUST_SEQ")
    @SequenceGenerator(sequenceName = "customer_seq", allocationSize = 1, name = "CUST_SEQ")
    Long id;
	
    String name;
    
	String email;

    @Column(name = "CREATED_DATE")
    Date date;

    //getters and setters, contructors
}

Configuration + Database Initialization

Configure Oracle data source, HikariCP settings and show Hibernate query.

application.properties
spring.main.banner-mode=off

# create and drop tables and sequences, loads import.sql
spring.jpa.hibernate.ddl-auto=create-drop

# Oracle settings
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:xe
spring.datasource.username=system
spring.datasource.password=password
spring.datasource.driver-class-oracle.jdbc.driver.OracleDriver

# HikariCP settings
# spring.datasource.hikari.*

spring.datasource.hikari.connection-timeout=60000
spring.datasource.hikari.maximum-pool-size=5

# logging
logging.pattern.console=%d{yyyy-MM-dd HH:mm:ss} %-5level %logger{36} - %msg%n
logging.level.org.hibernate.SQL=debug
#logging.level.org.hibernate.type.descriptor.sql=trace
logging.level.=error

If import.sql is found in the classpath, Hibernate will load it automatically.

import.sql
INSERT INTO "CUSTOMER" (ID, NAME, EMAIL, CREATED_DATE) VALUES(1, 'mkyong','111@yahoo.com', TO_DATE('2017-02-11', 'yyyy-mm-dd'));
INSERT INTO "CUSTOMER" (ID, NAME, EMAIL, CREATED_DATE) VALUES(2, 'yflow','222@yahoo.com', TO_DATE('2017-02-12', 'yyyy-mm-dd'));
INSERT INTO "CUSTOMER" (ID, NAME, EMAIL, CREATED_DATE) VALUES(3, 'zilap','333@yahoo.com', TO_DATE('2017-02-13', '

@Repository

Create an interface and extends Spring Data CrudRepository

CustomerRepository.java
package com.mkyong.dao;

import com.mkyong.model.Customer;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;

import java.util.Date;
import java.util.List;
import java.util.stream.Stream;

public interface CustomerRepository extends CrudRepository<Customer, Long> {

    List<Customer> findByEmail(String email);

    List<Customer> findByDate(Date date);

	// custom query example and return a stream
    @Query("select c from Customer c where c.email = :email")
    Stream<Customer> findByEmailReturnStream(@Param("email") String email);

}

Spring Boot Starter

Application.java
package com.mkyong;

import com.mkyong.dao.CustomerRepository;
import com.mkyong.model.Customer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.Transactional;

import javax.sql.DataSource;
import java.text.SimpleDateFormat;
import java.util.stream.Stream;

import static java.lang.System.exit;

@SpringBootApplication
public class Application implements CommandLineRunner {

    private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

    @Autowired
    DataSource dataSource;

    @Autowired
    CustomerRepository customerRepository;

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

    @Transactional(readOnly = true)
    @Override
    public void run(String... args) throws Exception {

        System.out.println("DATASOURCE = " + dataSource);

        System.out.println("\n1.findAll()...");
        for (Customer customer : customerRepository.findAll()) {
            System.out.println(customer);
        }

        System.out.println("\n2.findByEmail(String email)...");
        for (Customer customer : customerRepository.findByEmail("222@yahoo.com")) {
            System.out.println(customer);
        }

        System.out.println("\n3.findByDate(Date date)...");
        for (Customer customer : customerRepository.findByDate(sdf.parse("2017-02-12"))) {
            System.out.println(customer);
        }

        // For Stream, need @Transactional
        System.out.println("\n4.findByEmailReturnStream(@Param(\"email\") String email)...");
        try (Stream<Customer> stream = customerRepository.findByEmailReturnStream("333@yahoo.com")) {
            stream.forEach(x -> System.out.println(x));
        }

        System.out.println("Done!");

        exit(0);
    }

}

DEMO

Run it, read console for self-explanatory.

Terminal

2017-02-22 12:36:49 DEBUG org.hibernate.SQL - drop table customer cascade constraints
2017-02-22 12:36:49 ERROR o.h.tool.hbm2ddl.SchemaExport - HHH000389: Unsuccessful: drop table customer cascade constraints
2017-02-22 12:36:49 ERROR o.h.tool.hbm2ddl.SchemaExport - ORA-00942: table or view does not exist

2017-02-22 12:36:49 DEBUG org.hibernate.SQL - drop sequence customer_seq
2017-02-22 12:36:49 ERROR o.h.tool.hbm2ddl.SchemaExport - HHH000389: Unsuccessful: drop sequence customer_seq
2017-02-22 12:36:49 ERROR o.h.tool.hbm2ddl.SchemaExport - ORA-02289: sequence does not exist

2017-02-22 12:36:49 DEBUG org.hibernate.SQL - create sequence customer_seq start with 1 increment by 1
2017-02-22 12:36:49 DEBUG org.hibernate.SQL - create table customer (id number(19,0) not null, created_date timestamp, email varchar2(255 char), name varchar2(255 char), primary key (id))
DATASOURCE = HikariDataSource (HikariPool-1)

1.findAll()...
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - select customer0_.id as id1_0_, customer0_.created_date as created_date2_0_, customer0_.email as email3_0_, customer0_.name as name4_0_ from customer customer0_
Customer{id=1, name='mkyong', email='111@yahoo.com', date=2017-02-11 00:00:00.0}
Customer{id=2, name='yflow', email='222@yahoo.com', date=2017-02-12 00:00:00.0}
Customer{id=3, name='zilap', email='333@yahoo.com', date=2017-02-13 00:00:00.0}

2.findByEmail(String email)...
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - select customer0_.id as id1_0_, customer0_.created_date as created_date2_0_, customer0_.email as email3_0_, customer0_.name as name4_0_ from customer customer0_ where customer0_.email=?
Customer{id=2, name='yflow', email='222@yahoo.com', date=2017-02-12 00:00:00.0}

3.findByDate(Date date)...
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - select customer0_.id as id1_0_, customer0_.created_date as created_date2_0_, customer0_.email as email3_0_, customer0_.name as name4_0_ from customer customer0_ where customer0_.created_date=?
Customer{id=2, name='yflow', email='222@yahoo.com', date=2017-02-12 00:00:00.0}

4.findByEmailReturnStream(@Param("email") String email)...
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - select customer0_.id as id1_0_, customer0_.created_date as created_date2_0_, customer0_.email as email3_0_, customer0_.name as name4_0_ from customer customer0_ where customer0_.email=?
Customer{id=3, name='zilap', email='333@yahoo.com', date=2017-02-13 00:00:00.0}
Done!
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - drop table customer cascade constraints
2017-02-22 12:36:50 DEBUG org.hibernate.SQL - drop sequence customer_seq

Process finished with exit code 0

REFERENCE,

SPRING BOOT JPA EXAMPLE

SPRING OFFICIAL

Java Persistence API – JPACustomer Model. Add JPA annotations, and use “sequence ” to generate the auto increase primary ID.

Configuration + Database Initialization

@Repository

Spring Boot Starter

DEMO

Java Persistence API – JPA

Customer Model. Add JPA annotations, and use “sequence ” to generate the auto increase primary ID.