In this article, we will learn how to integrate Spring Data JPA into our Spring Boot application. We will be extending CrudRepository which in turn extends the Repository interface and hence there is no need for implementing our own methods. We will be creating a Student management application and store the details using Oracle database.
Spring Data REST takes the features of Spring HATEOAS and Spring Data JPA and combines them together automatically. Spring Data REST configuration is defined in a class called RepositoryRestMvcConfiguration and that class can just be imported into your application’s configuration
Creating table
Create STUDENT Table, simply Copy and Paste the following SQL query in the query editor to get the table created.
CREATE TABLE "STUDENT"
( "ID" NUMBER(10,0) NOT NULL ENABLE,
"NAME" VARCHAR2(255 CHAR),
"AGE" NUMBER(10,0) NOT NULL ENABLE,
PRIMARY KEY ("ID")
);
insert into "STUDENT" values (1,'JIP1',11);
insert into "STUDENT" values (2,'JIP2',22);
insert into "STUDENT" values (3,'JIP3',33);
insert into "STUDENT" values (4,'JIP4',44);
Spring Boot CRUDRepository Example
Folder Structure:
- Create a simple Maven Project “SpringBoot” by selecting maven-archetype-quickstart and create a package for our source files “com.javainterviewpoint” under src/main/java
- Now add the following dependency in the 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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.javainterviewpoint</groupId> <artifactId>SpringBoot</artifactId> <version>0.0.1-SNAPSHOT</version> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.1.RELEASE</version> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-rest</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>com.oracle</groupId> <artifactId>ojdbc14</artifactId> <version>11.2.0</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <source>1.7</source> <target>1.7</target> </configuration> </plugin> </plugins> </build> </project>
- Create the Java classes App.java,Student.java and StudentRepository.java under com.javainterviewpoint folder.
The spring-boot-starter-parent is a special starter, it provides useful Maven defaults. We will be using two using two additional Spring Boot Starters spring-boot-starter-data-jpa, spring-boot-starter-data-rest apart from spring-boot-starter-parent.
Dependency Tree
$ mvn dependency:tree [INFO] ------------------------------------------------------------------------ [INFO] Building SpringBoot 0.0.1-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] [INFO] --- maven-dependency-plugin:2.10:tree (default-cli) @ SpringBoot --- [INFO] com.javainterviewpoint:SpringBoot:jar:0.0.1-SNAPSHOT [INFO] +- org.springframework.boot:spring-boot-starter-data-rest:jar:1.5.1.RELEASE:compile [INFO] | +- org.springframework.boot:spring-boot-starter:jar:1.5.1.RELEASE:compile [INFO] | | +- org.springframework.boot:spring-boot:jar:1.5.1.RELEASE:compile [INFO] | | +- org.springframework.boot:spring-boot-autoconfigure:jar:1.5.1.RELEASE:compile [INFO] | | +- org.springframework.boot:spring-boot-starter-logging:jar:1.5.1.RELEASE:compile [INFO] | | | +- ch.qos.logback:logback-classic:jar:1.1.9:compile [INFO] | | | | \- ch.qos.logback:logback-core:jar:1.1.9:compile [INFO] | | | +- org.slf4j:jul-to-slf4j:jar:1.7.22:compile [INFO] | | | \- org.slf4j:log4j-over-slf4j:jar:1.7.22:compile [INFO] | | +- org.springframework:spring-core:jar:4.3.6.RELEASE:compile [INFO] | | \- org.yaml:snakeyaml:jar:1.17:runtime [INFO] | +- org.springframework.boot:spring-boot-starter-web:jar:1.5.1.RELEASE:compile [INFO] | | +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.5.1.RELEASE:compile [INFO] | | | +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.11:compile [INFO] | | | +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.11:compile [INFO] | | | \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.5.11:compile [INFO] | | +- org.hibernate:hibernate-validator:jar:5.3.4.Final:compile [INFO] | | | +- javax.validation:validation-api:jar:1.1.0.Final:compile [INFO] | | | \- com.fasterxml:classmate:jar:1.3.3:compile [INFO] | | +- org.springframework:spring-web:jar:4.3.6.RELEASE:compile [INFO] | | \- org.springframework:spring-webmvc:jar:4.3.6.RELEASE:compile [INFO] | | \- org.springframework:spring-expression:jar:4.3.6.RELEASE:compile [INFO] | +- com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile [INFO] | +- com.fasterxml.jackson.core:jackson-databind:jar:2.8.6:compile [INFO] | | \- com.fasterxml.jackson.core:jackson-core:jar:2.8.6:compile [INFO] | \- org.springframework.data:spring-data-rest-webmvc:jar:2.6.0.RELEASE:compile [INFO] | +- org.springframework.data:spring-data-rest-core:jar:2.6.0.RELEASE:compile [INFO] | | +- org.springframework.hateoas:spring-hateoas:jar:0.23.0.RELEASE:compile [INFO] | | +- org.springframework.plugin:spring-plugin-core:jar:1.2.0.RELEASE:compile [INFO] | | \- org.atteo:evo-inflector:jar:1.2.1:compile [INFO] | +- org.slf4j:slf4j-api:jar:1.7.22:compile [INFO] | \- org.slf4j:jcl-over-slf4j:jar:1.7.22:compile [INFO] +- org.springframework.boot:spring-boot-starter-data-jpa:jar:1.5.1.RELEASE:compile [INFO] | +- org.springframework.boot:spring-boot-starter-aop:jar:1.5.1.RELEASE:compile [INFO] | | +- org.springframework:spring-aop:jar:4.3.6.RELEASE:compile [INFO] | | \- org.aspectj:aspectjweaver:jar:1.8.9:compile [INFO] | +- org.springframework.boot:spring-boot-starter-jdbc:jar:1.5.1.RELEASE:compile [INFO] | | +- org.apache.tomcat:tomcat-jdbc:jar:8.5.11:compile [INFO] | | | \- org.apache.tomcat:tomcat-juli:jar:8.5.11:compile [INFO] | | \- org.springframework:spring-jdbc:jar:4.3.6.RELEASE:compile [INFO] | +- org.hibernate:hibernate-core:jar:5.0.11.Final:compile [INFO] | | +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile [INFO] | | +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile [INFO] | | +- org.javassist:javassist:jar:3.21.0-GA:compile [INFO] | | +- antlr:antlr:jar:2.7.7:compile [INFO] | | +- org.jboss:jandex:jar:2.0.0.Final:compile [INFO] | | +- dom4j:dom4j:jar:1.6.1:compile [INFO] | | \- org.hibernate.common:hibernate-commons-annotations:jar:5.0.1.Final:compile [INFO] | +- org.hibernate:hibernate-entitymanager:jar:5.0.11.Final:compile [INFO] | +- javax.transaction:javax.transaction-api:jar:1.2:compile [INFO] | +- org.springframework.data:spring-data-jpa:jar:1.11.0.RELEASE:compile [INFO] | | +- org.springframework.data:spring-data-commons:jar:1.13.0.RELEASE:compile [INFO] | | +- org.springframework:spring-orm:jar:4.3.6.RELEASE:compile [INFO] | | +- org.springframework:spring-context:jar:4.3.6.RELEASE:compile [INFO] | | +- org.springframework:spring-tx:jar:4.3.6.RELEASE:compile [INFO] | | \- org.springframework:spring-beans:jar:4.3.6.RELEASE:compile [INFO] | \- org.springframework:spring-aspects:jar:4.3.6.RELEASE:compile [INFO] \- com.oracle:ojdbc14:jar:11.2.0:compile [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 01:50 min [INFO] Finished at: 2017-07-14T12:33:28+05:30 [INFO] Final Memory: 18M/117M [INFO] ------------------------------------------------------------------------
application.properties
Place the application.properties file under the src/resources folder
#Oracle Connection settings spring.datasource.url=jdbc:oracle:thin:@rsh2:40051:mydb spring.datasource.username=root spring.datasource.password=password spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver #JPA properties spring.jpa.show-sql = true spring.jpa.hibernate.ddl-auto = update
StundentRepository.java
package com.javainterviewpoint;
import java.util.List;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;
@RepositoryRestResource
public interface StudentRepository extends CrudRepository<Student, Long>
{
public List<Student> findById(long id);
//@Query("select s from Student s where s.age <= ?")
public List<Student> findByAgeLessThanEqual (long age);
}
Spring Data REST will create an implementation of StudentRepository automatically during runtime.
@RepositoryRestResource annotation will direct Spring to create RESTful endpoints
App.java
package com.javainterviewpoint;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication(scanBasePackages =
{ "com.javainterviewpoint" })
public class App implements CommandLineRunner
{
@Autowired
StudentRepository studentRepository;
public static void main(String[] args)
{
SpringApplication.run(App.class, args);
}
@Override
public void run(String... args) throws Exception
{
// Getting all Students
System.out.println("***** All Students *******");
for(Student st : studentRepository.findAll())
{
System.out.println(st);
}
// Getting the student with id 2
System.out.println("***** Student with ID 2 *******");
for(Student st : studentRepository.findById(2))
{
System.out.println(st);
}
// Getting the student with id 2
System.out.println("***** Student with Age less than 33 *******");
for(Student st : studentRepository.findByAgeLessThanEqual(33))
{
System.out.println(st);
}
}
}
- @SpringBootApplication annotation does the work of @EnableAutoConfiguration, @Configuration and @ComponentScan annotations together
- CommandLineRunner interface has an unimplemented run() method, In our App class we have implemented the CommandLineRunner interface and have overridden the run() method. So when the SpringApplication.run() of the App class starts the spring boot application just before the application gets started, CommandLineRunner.run() will be executed.
Student.java
package com.javainterviewpoint;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Student
{
@Id
@GeneratedValue
@Column(name="ID")
private long id;
@Column(name="NAME")
private String name;
@Column(name="AGE")
private long age;
public Student()
{
super();
}
public Student(long id, String name, long age)
{
super();
this.id = id;
this.name = name;
this.age = age;
}
public long getId()
{
return id;
}
public void setId(long id)
{
this.id = id;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public long getAge()
{
return age;
}
public void setAge(long age)
{
this.age = age;
}
@Override
public String toString()
{
return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
Our Student class is a simple POJO class consisting of the getters and setters for the Student class properties (id, name, age).
In the POJO class, we have used the below JPA Annotations.
- @Entity – This annotation will mark our Employee class as an Entity Bean.
- @Table – @Table annotation will map our class to the corresponding database table. You can also specify other attributes such as indexes, catalog, schema, uniqueConstraints. The @Table annotation is an optional annotation if this annotation is not provided then the class name will be used as the table name.
- @Id – The @Id annotation marks the particular field as the primary key of the Entity.
- @GeneratedValue – This annotation is used to specify how the primary key should be generated. Here SEQUENCE Strategy will be used as this the default strategy for Oracle
Output
Run our application using the command “mvn spring-boot:run”, you will get the below output
***** All Students ******* 2017-07-14 13:47:41.076 INFO 4424 --- [ main] o.h.h.i.QueryTranslatorFactoryInitiator : HHH000397: Using ASTQueryTranslatorFactory Hibernate: select student0_.id as id1_0_, student0_.age as age2_0_, student0_.name as name3_0_ from student student0_ Student [id=1, name=JIP1, age=11] Student [id=2, name=JIP2, age=22] Student [id=3, name=JIP3, age=33] Student [id=4, name=JIP4, age=44] ***** Student with ID 2 ******* Hibernate: select student0_.id as id1_0_, student0_.age as age2_0_, student0_.name as name3_0_ from student student0_ where student0_.id=? Student [id=2, name=JIP2, age=22] ***** Student with Age less than 33 ******* Hibernate: select student0_.id as id1_0_, student0_.age as age2_0_, student0_.name as name3_0_ from student student0_ where student0_.age<=? Student [id=1, name=JIP1, age=11] Student [id=2, name=JIP2, age=22] Student [id=3, name=JIP3, age=33]
On the other hand, issue a GET request (http://localhost:8080/) and it will return a JSON response.Under the _links section you can see there will be two links
- http://localhost:8080/students (Name of the class with ‘s’ added)
- http://localhost:8080/profile (Reference of ourself)
Now click on the http://localhost:8080/students link you will get all the students added.
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