Spring Data CrudRepository saveAll() and findAll()

In this article, we will see about Spring Data CrudRepository saveAll() and findAll() Methods Example using Spring Boot and Oracle.

Spring Data JPA Interview Questions and Answers
How to write a custom method in the repository in Spring Data JPA

CrudRepository interface extends the Repository interface. In Spring Data JPA Repository is a top-level interface in hierarchy. The saveAll() method has been defined as below.

Iterable saveAll(Iterable entities) – used to save multiple entities.
The saveAll() method internally annotated with @Transactional. See a depth tutorial which explains why we need @Transactional annotation here.

The implementation of CrudRepository’s saveAll() method has been given in SimpleJpaRepository.java and saveAll() method internally uses save() method only as below.

	@Transactional
	public <S extends T> List<S> saveAll(Iterable<S> entities) {

		List<S> result = new ArrayList<S>();

		for (S entity : entities) {
			result.add(save(entity));
		}

		return result;
	}

Just an additional note the CrudRepository’s save() method is used to perform save as well as an update operation. If we try to save entity first time then persist() method will get invoked and if we try to update the same entity merge() will get invoked. Observe the below implementation of save() method.

	public S save(S entity) {
 
		if (entityInformation.isNew(entity)) {
		em.persist(entity);
		return entity;
		} else {
		return em.merge(entity);
		}
	}
Note - See a depth tutorial that explains differences between JPA and Hibernate.

The findAll() method has been defined as below.

Iterable<T> findAll();

The findAll() internally defined as below.

public List<T> findAll() {
return getQuery(null, Sort.unsorted()).getResultList();
}

Let’s see in below code how we are going to use the CrudRepository’s saveAll() and findAll() methods.

package com.javatute.impl;

import java.util.List;

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

import com.javatute.entity.Student;
import com.javatute.repository.StudentRepository;
import com.javatute.service.StudentService;

@Service("studentServiceImpl")
public class StudentServiceImpl implements StudentService {

	@Autowired
	private StudentRepository studentRepository;

	@Transactional
	public List<Student> saveAllStudent(List<Student> studentList) {
		List<Student> response = (List<Student>) studentRepository.saveAll(studentList);
		return response;
	}
	
	@Transactional
	public List<Student> getAllStudents() {
		List<Student> studentResponse = (List<Student>) studentRepository.findAll();
		return studentResponse;
	}
	

}

Let’s see an example of Spring Data CrudRepository saveAll() and findAll() Methods for create and get the entities.

Open eclipse and create maven project, Don’t forget to check ‘Create a simple project (skip)’ click on next.  Fill all details(GroupId – springdatasaveall, ArtifactId – springdatasaveall and name – springdatasaveall) and click on finish. Keep packaging as the jar.

Modify 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/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>springdatasaveall</groupId>
	<artifactId>springdatasaveall</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>springdatasaveall</name>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.2.RELEASE</version>
	</parent>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>

		</dependency>

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

		<dependency>
			<groupId>com.oracle</groupId>
			<artifactId>ojdbc6</artifactId>
			<version>11.2.0.3</version>
		</dependency>

	</dependencies>
	<build>
		<finalName>${project.artifactId}</finalName>
		<plugins>

			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.1</version>
				<configuration>
					<fork>true</fork>
					<executable>C:\Program Files\Java\jdk1.8.0_131\bin\javac.exe</executable>
				</configuration>
			</plugin>


		</plugins>
	</build>
</project>

Note – In pom.xml we have defined javac.exe path in configuration tag. You need to change accordingly i.e where you have installed JDK.

If you see any error for oracle dependency then follow these steps.

Directory structure –

Student.java

package com.javatute.entity;

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

@Entity
public class Student {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int id;

	@Column(name = "name")
	private String name;

	@Column(name = "roll_number")
	private String rollNumber;

	@Column(name = "university")
	String university;

	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 String getRollNumber() {
		return rollNumber;
	}

	public void setRollNumber(String rollNumber) {
		this.rollNumber = rollNumber;
	}

	public String getUniversity() {
		return university;
	}

	public void setUniversity(String university) {
		this.university = university;
	}

}

StudentController.java

package com.javatute.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.javatute.entity.Student;
import com.javatute.service.StudentService;

@RestController
@RequestMapping(value = "/student")
public class StudentController {

	@Autowired
	private StudentService studentService;

	@RequestMapping(value = "/saveall", method = RequestMethod.POST)
	@ResponseBody
	public List<Student> saveAllStudents(@RequestBody List<Student> studentList) {
		List<Student> studentResponse = (List<Student>) studentService.saveAllStudent(studentList);
		return studentResponse;
	}
	
	
	@RequestMapping(value = "/getall", method = RequestMethod.GET)
	@ResponseBody
	public List<Student> getAllStudents() {
		List<Student> studentResponse = (List<Student>) studentService.getAllStudents();
		return studentResponse;
	}

}

See more details about @Controller and RestController here.

StudentRepository.java – interface

package com.javatute.repository;

import java.io.Serializable;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.javatute.entity.Student;

@Repository
public interface StudentRepository extends CrudRepository<Student, Serializable> {

}

StudentService.java – interface

package com.javatute.service;

import java.util.List;

import org.springframework.stereotype.Component;

import com.javatute.entity.Student;

@Component
public interface StudentService {
	public List<Student> saveAllStudent(List<Student> studentList);
	public List<Student> getAllStudents();
	
}

StudentServiceImpl.java

package com.javatute.impl;

import java.util.List;

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

import com.javatute.entity.Student;
import com.javatute.repository.StudentRepository;
import com.javatute.service.StudentService;

@Service("studentServiceImpl")
public class StudentServiceImpl implements StudentService {

	@Autowired
	private StudentRepository studentRepository;

	@Transactional
	public List<Student> saveAllStudent(List<Student> studentList) {
		List<Student> response = (List<Student>) studentRepository.saveAll(studentList);
		return response;
	}
	
	@Transactional
	public List<Student> getAllStudents() {
		List<Student> studentResponse = (List<Student>) studentRepository.findAll();
		return studentResponse;
	}
	

}

Note – See here more about @Component, @Controller, @Service and @Repository annotations here.

SpringMain.java

package com.javatute.main;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = "com.*")
@EntityScan("com.javatute.entity")
public class SpringMain {
	public static void main(String[] args) {

		SpringApplication.run(SpringMain.class, args);
	}

}

Note – See more details about @ComponentScan here.

JpaConfig.java

package com.javatute.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@Configuration
@EnableJpaRepositories(basePackages = "com.javatute.repository")
public class JpaConfig {

}

Note – See more details about @Configuration annotations here.

application.properties

# Connection url for the database
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.username=SYSTEM
spring.datasource.password=oracle2
spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
# Show or not log for each sql query
spring.jpa.show-sql = true
 
 
spring.jpa.hibernate.ddl-auto =create
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.Oracle10gDialect
 
server.port = 9091

Let’s run the SpringMain class(run as java application).

Perform save operation first using below REST API.

http://localhost:9091/student/saveall

Request Data –

[
    {
        "name": "Hiteshdo",
        "rollNumber": "0126CS01",
        "university":"rgtu"
    },
    {
        "name": "Johnhjhjhjhj",
        "rollNumber": "0126CS02",
        "university":"rgtu"
    },
    {
        "name": "Mohankkkkkkkkkkkkkk",
        "rollNumber": "0126CS03",
        "university":"rgtu"
    },
    {
        "name": "Nagesh",
        "rollNumber": "0126CS04",
        "university":"rgtu"
    },
    {
        "name": "s",
        "rollNumber": "0126CS05",
        "university":"rgtu"
    },
    {
        "name": "Ranakum",
        "rollNumber": "0126CS06",
        "university":"rgtu"
    },
    {
        "name": "Roc",
        "rollNumber": "0126CS07",
        "university":"rgtu"
    },
    {
        "name": "Simpy",
        "rollNumber": "0126CS08",
        "university":"rgtu"
    },
    {
        "name": "Tiwari",
        "rollNumber": "0126CS09",
        "university":"rgtu"
    },    {
        "name": "Appu",
        "rollNumber": "0126CS10",
        "university":"rgtu"
    },
    {
        "name": "Babloo",
        "rollNumber": "0126CS11",
        "university":"rgtu"
    },
    {
        "name": "Ga",
        "rollNumber": "0126CS12",
        "university":"rgtu"
    }
]

Response Data –

[
    {
        "id": 1,
        "name": "Hiteshdo",
        "rollNumber": "0126CS01",
        "university": "rgtu"
    },
    {
        "id": 2,
        "name": "Johnhjhjhjhj",
        "rollNumber": "0126CS02",
        "university": "rgtu"
    },
    {
        "id": 3,
        "name": "Mohankkkkkkkkkkkkkk",
        "rollNumber": "0126CS03",
        "university": "rgtu"
    },
    {
        "id": 4,
        "name": "Nagesh",
        "rollNumber": "0126CS04",
        "university": "rgtu"
    },
    {
        "id": 5,
        "name": "s",
        "rollNumber": "0126CS05",
        "university": "rgtu"
    },
    {
        "id": 6,
        "name": "Ranakum",
        "rollNumber": "0126CS06",
        "university": "rgtu"
    },
    {
        "id": 7,
        "name": "Roc",
        "rollNumber": "0126CS07",
        "university": "rgtu"
    },
    {
        "id": 8,
        "name": "Simpy",
        "rollNumber": "0126CS08",
        "university": "rgtu"
    },
    {
        "id": 9,
        "name": "Tiwari",
        "rollNumber": "0126CS09",
        "university": "rgtu"
    },
    {
        "id": 10,
        "name": "Appu",
        "rollNumber": "0126CS10",
        "university": "rgtu"
    },
    {
        "id": 11,
        "name": "Babloo",
        "rollNumber": "0126CS11",
        "university": "rgtu"
    },
    {
        "id": 12,
        "name": "Ga",
        "rollNumber": "0126CS12",
        "university": "rgtu"
    }
]

http://localhost:9091/student/getall

[
    {
        "id": 1,
        "name": "Hiteshdo",
        "rollNumber": "0126CS01",
        "university": "rgtu"
    },
    {
        "id": 2,
        "name": "Johnhjhjhjhj",
        "rollNumber": "0126CS02",
        "university": "rgtu"
    },
    {
        "id": 3,
        "name": "Mohankkkkkkkkkkkkkk",
        "rollNumber": "0126CS03",
        "university": "rgtu"
    },
    {
        "id": 4,
        "name": "Nagesh",
        "rollNumber": "0126CS04",
        "university": "rgtu"
    },
    {
        "id": 5,
        "name": "s",
        "rollNumber": "0126CS05",
        "university": "rgtu"
    },
    {
        "id": 6,
        "name": "Ranakum",
        "rollNumber": "0126CS06",
        "university": "rgtu"
    },
    {
        "id": 7,
        "name": "Roc",
        "rollNumber": "0126CS07",
        "university": "rgtu"
    },
    {
        "id": 8,
        "name": "Simpy",
        "rollNumber": "0126CS08",
        "university": "rgtu"
    },
    {
        "id": 9,
        "name": "Tiwari",
        "rollNumber": "0126CS09",
        "university": "rgtu"
    },
    {
        "id": 10,
        "name": "Appu",
        "rollNumber": "0126CS10",
        "university": "rgtu"
    },
    {
        "id": 11,
        "name": "Babloo",
        "rollNumber": "0126CS11",
        "university": "rgtu"
    },
    {
        "id": 12,
        "name": "Ga",
        "rollNumber": "0126CS12",
        "university": "rgtu"
    }
]

That’s all about Spring Data CrudRepository saveAll() and findAll() Method Example Using Spring Boot and Oracle.

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Spring Data CrudRepository  Docs.