SPRING BOOT REST

learn how to integrate SPRING DATA JPA into our spring applications. We will be extending JPARepository

Create EMPLOYEE Table, simply Copy and Paste the following SQL query in the query editor to get the table created.

CREATE TABLE "EMPLOYEE" 
 ( 
    "ID" NUMBER(10) NOT NULL ENABLE, 
    "AGE" NUMBER(10), 
    "DEPT" VARCHAR2(255 CHAR), 
    "NAME" VARCHAR2(255 CHAR), 
     PRIMARY KEY ("ID")
 );

1. Create a simple Maven Project “SpringDataJPA” by selecting maven-archetype-quickstart  and create a package for our source files “com.javainterviewpoint”under  src/main/java 
2. Now add the following dependency in the 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.javainterviewpoint</groupId>
   	<artifactId>SpringJPA</artifactId>
   	<packaging>jar</packaging>
   	<version>0.0.1-SNAPSHOT</version>
   	<name>SpringJPA Maven Webapp</name>
   	<url>http://maven.apache.org</url>
   	<properties>
   		<hibernate.version>4.2.0.Final</hibernate.version>
   		<mysql.connector.version>5.1.21</mysql.connector.version>
   		<spring.version>4.3.5 RELEASE</spring.version>
   	</properties>
   
   
   	<dependencies>
   		<dependency>
   			<groupId>cglib</groupId>
   			<artifactId>cglib</artifactId>
   			<version>${cglib.version}</version>
   		</dependency>
   
   		<!-- DB related dependencies -->
   
   		<dependency>
   			<groupId>org.hibernate.common</groupId>
   			<artifactId>hibernate-commons-annotations</artifactId>
   			<version>4.0.4.Final</version>
   		</dependency>
   		<dependency>
   			<groupId>commons-dbcp</groupId>
   			<artifactId>commons-dbcp</artifactId>
   			<version>1.4</version>
   		</dependency>
   		<dependency>
   			<groupId>javassist</groupId>
   			<artifactId>javassist</artifactId>
   			<version>3.12.1.GA</version>
   		</dependency>
   		<dependency>
   			<groupId>org.hibernate.javax.persistence</groupId>
   			<artifactId>hibernate-jpa-2.0-api</artifactId>
   			<version>1.0.1.Final</version>
   		</dependency>
   		<!-- SPRING -->
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-webmvc</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-core</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-tx</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-jdbc</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-orm</artifactId>
   			<version>3.2.5.RELEASE</version>
   		</dependency>
   		<!-- CGLIB is required to process @Configuration classes -->
   		<dependency>
   			<groupId>cglib</groupId>
   			<artifactId>cglib</artifactId>
   			<version>2.2.2</version>
   		</dependency>
   		<!-- Servlet API and JSTL -->
   		<dependency>
   			<groupId>javax.servlet</groupId>
   			<artifactId>javax.servlet-api</artifactId>
   			<version>3.0.1</version>
   			<scope>provided</scope>
   		</dependency>
   		<dependency>
   			<groupId>jstl</groupId>
   			<artifactId>jstl</artifactId>
   			<version>1.2</version>
   		</dependency>
   
   		<!-- Test -->
   		<dependency>
   			<groupId>junit</groupId>
   			<artifactId>junit</artifactId>
   			<version>4.7</version>
   			<scope>test</scope>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-test</artifactId>
   			<version>4.3.5.RELEASE</version>
   			<scope>test</scope>
   		</dependency>
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-test-mvc</artifactId>
   			<version>1.0.0.M1</version>
   			<scope>test</scope>
   		</dependency>
   		<!-- https://mvnrepository.com/artifact/org.springframework.data/spring-data-jpa -->
   		<dependency>
   			<groupId>org.springframework.data</groupId>
   			<artifactId>spring-data-jpa</artifactId>
   			<version>1.11.3.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>com.oracle</groupId>
   			<artifactId>ojdbc14</artifactId>
   			<version>11.2.0</version>
   		</dependency>
   		<dependency>
   			<groupId>org.hibernate</groupId>
   			<artifactId>hibernate-core</artifactId>
   			<version>4.1.9.Final</version>
   		</dependency>
   		<!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-tx</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
   		<dependency>
   			<groupId>org.springframework</groupId>
   			<artifactId>spring-context</artifactId>
   			<version>4.3.5.RELEASE</version>
   		</dependency>
   		<dependency>
   			<groupId>org.hibernate</groupId>
   			<artifactId>hibernate-entitymanager</artifactId>
   			<version>4.1.9.Final</version>
   		</dependency>
   	</dependencies>
   	<build>
   		<finalName>SpringJPA</finalName>
   	</build>
   </project>

3. Create the Java classes EmployeeService.java, EmployeeServiceImpl.java, EmployeeRepository.java, Employee.java, and App.java under com.javainterviewpoint folder.

SPRING BOOT JPA CRUD Example

EmployeeRepository.java

package com.javainterviewpoint;

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

public interface EmployeeRepository extends JpaRepository<Employee,Integer>
{

}

We have extended JpaRepository in our EmployeeRepository class, that’s all we need to do. We will be able to perform CRUD Operations using the built-in methods of JpaRepository.

EmployeeService.java

package com.javainterviewpoint;

import java.util.List;

public interface EmployeeService
{
    public abstract Employee getEmployeeById(int id);
    public abstract void saveEmployee(Employee employee);
    public abstract void updateEmployee(Employee employee);
    public abstract void deleteEmployee(int id);
    public abstract List<Employee> getAllEmployees();
}

EmployeeService is a simple interface to perform CRUD Operation, implementation will be provided by EmployeeServiceImpl class.

EmployeeServiceImpl.java

package com.javainterviewpoint;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;

@Component
public class EmployeeServiceImpl implements EmployeeService
{
    @Autowired
    private EmployeeRepository employeeRepository;
    
    @Transactional
    public Employee getEmployeeById(int id)
    {
        return employeeRepository.findOne(id);
    }
    @Transactional
    public void saveEmployee(Employee employee)
    {
        employeeRepository.save(employee);
    }
    @Transactional
    public void updateEmployee(Employee employee)
    {
        employeeRepository.save(employee);       
    }
    @Transactional
    public void deleteEmployee(int id)
    {
        employeeRepository.delete(id);
    }
    @Transactional
    public List<Employee> getAllEmployees()
    {
       return employeeRepository.findAll();
    }
}

We have implemented the EmployeeService interface and auto-wired EmployeeRepositoryclass. We will be using findOne(), save(), delete(), findAll() method of JpaRepository class to perform CRUD.

SpringConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:jpa="http://www.springframework.org/schema/data/jpa"
	xsi:schemaLocation="http://www.springframework.org/schema/jdbc		http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsd
		http://www.springframework.org/schema/beans		http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/tx/	http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
		http://www.springframework.org/schema/context	http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/mvc	http://www.springframework.org/schema/mvc/spring-mvc.xsd
		http://www.springframework.org/schema/data/jpa	http://www.springframework.org/schema/data/jpa/spring-jpa-1.2.xsd">

     <context:component-scan base-package="com.javainterviewpoint"></context:component-scan>
     <jpa:repositories base-package="com.javainterviewpoint"
        entity-manager-factory-ref="entityManagerFactoryBean"></jpa:repositories>
     <bean id="employeeServiceImpl" class="com.javainterviewpoint.EmployeeServiceImpl" />

     <!--EntityManagerFactory -->
     <bean id="entityManagerFactoryBean"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- This makes /META-INF/persistence.xml is no longer necessary -->
        <property name="packagesToScan" value="com.javainterviewpoint" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
        <property name="jpaProperties">
        <props>
           <prop key="hibernate.hbm2ddl.auto">update</prop>
           <prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
        </props>
        </property>
      </bean>

     <bean id="dataSource"
          class="org.springframework.jdbc.datasource.DriverManagerDataSource">
         <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
         <property name="url" value="jdbc:oracle:thin:@rsh2:40051:mydb" />
         <property name="username" value="root" />
         <property name="password" value="root" />
      </bean>

      <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
         <property name="entityManagerFactory" ref="entityManagerFactoryBean" />
      </bean>
  <tx:annotation-driven />
</beans>

Below are the configurations which has been made in the above config file.

• Configure the data source bean

  <bean id="dataSource"
          class="org.springframework.jdbc.datasource.DriverManagerDataSource">
         <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
         <property name="url" value="jdbc:oracle:thin:@rsh2:40051:mydb" />
         <property name="username" value="root" />
         <property name="password" value="root" />
      </bean>

• Configure the entity manager factory bean

 <bean id="entityManagerFactoryBean"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- This makes /META-INF/persistence.xml is no longer necessary -->
        <property name="packagesToScan" value="com.javainterviewpoint" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
        <property name="jpaProperties">
        <props>
           <prop key="hibernate.hbm2ddl.auto">update</prop>
           <prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
        </props>
        </property>
      </bean>

• Configure the transaction manager bean

   <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
         <property name="entityManagerFactory" ref="entityManagerFactoryBean" />
      </bean>

• In the <jpa:repositories> tag we need to pass our “entityManagerFactoryBean”reference

      <jpa:repositories base-package="com.javainterviewpoint"
        entity-manager-factory-ref="entityManagerFactoryBean"></jpa:repositories>

App.java

package com.javainterviewpoint;

import java.util.List;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App 
{
    public static void main( String[] args )
    {
        //Reading the Configuration file
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("springConfig.xml");
        
        //Get the EmployeeServiceImpl bean
        EmployeeServiceImpl employeeServiceImpl = (EmployeeServiceImpl)context.getBean("employeeServiceImpl");
        
        //Create Employee object
        Employee employee = new Employee();
        employee.setAge(55);
        employee.setDept("Blogging");
        employee.setName("JIP");
        
        //Save the new Employee
        employeeServiceImpl.saveEmployee(employee);
        //Read the Employee 
        Employee emp = employeeServiceImpl.getEmployeeById(1);
        //Retrieve all the Employees
        List<Employee> employeeList = employeeServiceImpl.getAllEmployees();
        System.out.println("*** List of all Employees *** ");
        for(Employee emp1 : employeeList)
        {
            System.out.println("Employee Id   :"+emp1.getId());
            System.out.println("Employee Name :"+emp1.getName());
            System.out.println("Employee Age  :"+emp1.getAge());
            System.out.println("Department :"+emp1.getDept());
            System.out.println();
        }
        System.out.println("*************************************");
        
        //Delete Employee
        employeeServiceImpl.deleteEmployee(1);
        
        context.close();
    }
}

• ClassPathXmlApplicationContext  reads our Configuration File(SpringConfig.xml)
• BeanFactory class read all the bean definition mentioned in the config file.
• Get the EmployeeServiceImpl Class instance by calling the getBean() method over the bean factory.
• We will be calling the saveEmployee(), getEmployeeById(), getAllEmployees() anddeleteEmployee() of the EmployeeServiceImpl Class.

Employee.java

package com.javainterviewpoint;

import java.io.Serializable;

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 implements Serializable 
{
    private static final long serialVersionUID = -889976693182180703L;
    
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="ID")
    private int id;
    
    @Column(name="NAME")
    private String name;
    
    @Column(name="AGE")
    private int age;
    
    @Column(name="DEPT")
    private String dept;
    
    public Employee()
    {
        super();
    }

    public Employee(int id, String name, int age, String dept)
    {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
        this.dept = dept;
    }
    
    public int getId()
    {
        return id;
    }
    public void setId(int id)
    {
        this.id = id;
    }
    public String getName()
    {
        return name;
    }
    public void setName(String name)
    {
        this.name = name;
    }
    public int getAge()
    {
        return age;
    }
    public void setAge(int age)
    {
        this.age = age;
    }
    public String getDept()
    {
        return dept;
    }
    public void setDept(String dept)
    {
        this.dept = dept;
    }
    @Override
    public String toString()
    {
        return "Employee [id=" + id + ", name=" + name + ", age=" + age + ", dept=" + dept + "]";
    }
    @Override
    public int hashCode()
    {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((dept == null) ? 0 : dept.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj)
    {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Employee other = (Employee) obj;
        if (age != other.age)
            return false;
        if (dept == null)
        {
            if (other.dept != null)
                return false;
        } else if (!dept.equals(other.dept))
            return false;
        if (id != other.id)
            return false;
        if (name == null)
        {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

Our Employee class is a simple POJO class consisting getters and setters of its properties.

output:

*** List of all Employees *** 
Employee Id   :1
Employee Name :JIP1
Employee Age  :99
Department :IT

Employee Id   :4
Employee Name :aaaa
Employee Age  :4
Department :test

Employee Id   :3
Employee Name :JIP3333
Employee Age  :33333
Department :IT

Employee Id   :141
Employee Name :JIP
Employee Age  :55
Department :Blogging

RESOURCES:

https://www.linkedin.com/pulse/spring-boot-rest-api-example-billgate-william/

https://projects.spring.io/spring-boot/

https://goo.gl/3iNmyt