Spring Boot + Apache Commons Export Data to CSV Example

Hello everyone, today we will learn how to export and download the data as a CSV file in a Spring Boot project. CSV stands for Comma-Separated-Values and it's a common format for doing a bulk data transfer between systems. For creating and parsing CSV files, we will use Apache Commons' 3rd-party library. 


Technologies used 

  • Spring Boot
  • Apache Commons
  • Spring Data JPA
  • H2DB
  • Maven

Project directory



Maven[pom.xml] 

A Project Object Model or POM is the fundamental unit of work in Maven. It is an XML file that contains information about the project and configuration details utilized by Maven to build the project. It contains default values for most projects. Some of the configurations that can be designated in the POM is the project dependencies, the plugins or goals that can be executed, the build profiles, and so on. Other information such as the project version, description, developers, mailing lists, and such can withal be designated.

<?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>2.1.1.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>springboot_export_csv_apache_commons</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>springboot_export_csv_apache_commons</name>
<description>Demo project for Spring Boot</description>

<properties>
<java.version>1.8</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.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.8</version>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>


Model class[Employee.java]

package com.example.demo.model;

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 {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
private String name;
private String email;
private String country;
private int age;
private String role;

public Employee() {
super();
}

public Employee(String name, String email, String country,
int age, String role) {
super();

this.name = name;
this.email = email;
this.country = country;
this.age = age;
this.role = role;
}

public String getRole() {
return role;
}

public void setRole(String role) {
this.role = role;
}

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 String getEmail() {
return email;
}

public void setEmail(String email) {
this.email = email;
}

public String getCountry() {
return country;
}

public void setCountry(String country) {
this.country = country;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

}


DAO layer[EmployeeRepository.java]

package com.example.demo.repository;

import org.springframework.data.repository.CrudRepository;
import com.example.demo.model.Employee;

public interface EmployeeRepository extends CrudRepository<Employee, Long> {

}


Service layer[EmployeeService.java]

package com.example.demo.service;

import java.io.ByteArrayInputStream;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.example.demo.helper.CSVHelper;
import com.example.demo.model.Employee;
import com.example.demo.repository.EmployeeRepository;

@Service
public class EmployeeService {
@Autowired
EmployeeRepository employeeRepository;

public List<Employee> fetchAll() {
return (List<Employee>) employeeRepository.findAll();

}

public ByteArrayInputStream load() {
List<Employee> tutorials = fetchAll();

ByteArrayInputStream in = CSVHelper.employeesToCSV(tutorials);
return in;
}
}


CSVHelper.java

package com.example.demo.helper;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
import org.apache.tomcat.util.http.fileupload.ByteArrayOutputStream;
import com.example.demo.model.Employee;

public class CSVHelper {

public static ByteArrayInputStream employeesToCSV(List<Employee> employees)
{
final CSVFormat format = CSVFormat.DEFAULT.withHeader
("ID", "Name", "Email", "Age", "Country", "Role");

try (

ByteArrayOutputStream out = new ByteArrayOutputStream();
CSVPrinter csvPrinter = new CSVPrinter(new PrintWriter(out),
format);) {
for (Employee emp : employees) {
List<String> data = Arrays.asList(String.valueOf(emp.getId()),
emp.getName(), emp.getEmail(),
String.valueOf(emp.getAge()), emp.getCountry(),
emp.getRole());

csvPrinter.printRecord(data);
}

csvPrinter.flush();
return new ByteArrayInputStream(out.toByteArray());
} catch (IOException e) {
throw new RuntimeException("fail to import data to CSV file: "
+ e.getMessage());
}
}
}


EmployeeController.java

package com.example.demo.controller;

import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import com.example.demo.service.EmployeeService;

@Controller
public class EmployeeController {

@Autowired
EmployeeService employeeService;

@GetMapping("/export-employees")
public ResponseEntity<InputStreamResource>
exportCSV(HttpServletResponse response) throws Exception {

String filename = "employees.csv";
InputStreamResource file = new InputStreamResource
(employeeService.load());

return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
"attachment; filename=" + filename)
.contentType(MediaType.parseMediaType("application/csv")).
body(file);

}
}


Spring Boot Main[SpringbootExportCsvDemoApplication.java]

package com.example.demo;

import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import com.example.demo.model.Employee;
import com.example.demo.repository.EmployeeRepository;

@SpringBootApplication
public class SpringbootExportCsvDemoApplication implements CommandLineRunner {
@Autowired
EmployeeRepository employeeRepository;

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

@Override
public void run(String... args) throws Exception {
List<Employee> employees = new ArrayList<>();

// create dummy employees
employees.add(new Employee("Dummy-1", "dummy1@example.com",
"India", 35, "Lead Tester"));
employees.add(new Employee("Dummy-2", "dummy2@srovoki.me",
"USA", 25, "Tester"));
employees.add(new Employee("Dummy-3", "dummy3@gmail.com",
"Japan", 29, "Sr.Tester"));
employees.add(new Employee("Dummy-1", "dummy1@example.com",
"India", 35, "Lead Tester"));
employees.add(new Employee("Dummy-2", "dummy2@srovoki.me",
"USA", 25, "Tester"));
employees.add(new Employee("Dummy-3", "dummy3@gmail.com",
"Japan", 29, "Sr.Tester"));
employees.add(new Employee("Dummy-1", "dummy1@example.com",
"India", 35, "Lead Tester"));
employees.add(new Employee("Dummy-2", "dummy2@srovoki.me",
"USA", 25, "Tester"));
employees.add(new Employee("Dummy-3", "dummy3@gmail.com",
"Japan", 29, "Sr.Tester"));
employees.add(new Employee("Dummy-1", "dummy1@example.com",
"India", 35, "Lead Tester"));
employees.add(new Employee("Dummy-2", "dummy2@srovoki.me",
"USA", 25, "Tester"));
employees.add(new Employee("Dummy-3", "dummy3@gmail.com",
"Japan", 29, "Sr.Tester"));
employees.add(new Employee("Dummy-1", "dummy1@example.com",
"India", 35, "Lead Tester"));
employees.add(new Employee("Dummy-2", "dummy2@srovoki.me",
"USA", 25, "Tester"));
employees.add(new Employee("Dummy-3", "dummy3@gmail.com",
"Japan", 29, "Sr.Tester"));
employeeRepository.saveAll(employees);
}

}


Run & Test 

Run Spring Boot application with the command: mvn spring-boot:run

Hit this URL in your local system, http://localhost:8080/export-employees


Open the downloaded CSV file






Popular posts from this blog

Spring boot video streaming example-HTML5

Learn Java 8 streams with an example - print odd/even numbers from Array and List

Spring Boot + Mockito simple application with 100% code coverage

Spring Boot + OpenCSV Export Data to CSV Example

Custom Exception Handling in Quarkus REST API

DataTable-Pagination example with Spring boot, jQuery and ajax

Registration and Login with Spring Boot + Spring Security + Thymeleaf

Node JS mini projects with source code - free download

Spring boot web project free download:User Registration System

Java - Blowfish Encryption and decryption Example