Spring Boot - Testing JDBC components with @JdbcTest - Example

In this section, we will learn how to test JDBC-based components with @JdbcTest in Spring Boot application.

1. @JdbcTest

Instead of bootstrapping the entire application context for every test, @JdbcTest allows us to initialize the Spring application context with only those beans needed to test JDBC-based components. It will auto-configure DataSource, and JdbcTemplate. 

If an embedded database is available on the classpath, @JdbcTest will autoconfigure one for testing purposes.

By default, tests annotated with @JdbcTest are transactional and roll back at the end of each test, means we do not need to clean up saved or modified table data after each test.

Regular @Component, @Repository, @Service or @Controller beans are not scanned when using this annotation. 

This approach not only speeds up the testing process but also ensures a focused and efficient testing environment.

This approach is also known as "slicing" the application context.

Find the sample code snippet to use @JdbcTest annotation in unit test class. 

@JdbcTest
public class StudentDAOTests{

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    void findByName_ReturnsTheStudent() {

        //todo...
    }
}

When using JUnit 4, this annotation should be used in combination with @RunWith(SpringRunner.class). But for this example  we are using JUnit 5, there’s no need to add the equivalent @ExtendWith(SpringExtension.class).


2. Transactions

By default, tests annotated with @JdbcTest are transactional and roll back at the end of each test. We can disable transaction management for a test, use Propagation.NOT_SUPPORTED.

@JdbcTest
@Transactional(propagation = Propagation.NOT_SUPPORTED)
public class StudentDAOTests{

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    void findByName_ReturnsTheStudent() {

        //todo...
    }
}


3. Test Against a Real Database

If you want run the tests against an application configured real database, use Replace.NONE.

@JdbcTest
@AutoConfigureTestDatabase(replace= AutoConfigureTestDatabase.Replace.NONE)//Testing with real database
public class StudentDAOTests{

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    void findByName_ReturnsTheStudent() {

       //todo...
    }
}


Complete example

Next we will create a spring boot JDBC application, create DAO layer which contains three methods and finally we will write test against H2 in-memory database.

4. Creating spring boot application

First, open the Spring initializr https://start.spring.io

Then, Provide the Group and Artifact name. We have provided Group name com.knf.dev.demo and Artifact jdbctest-example. Here I selected the Maven project - language Java 17 - Spring Boot 3.1.5 , JDBC API, and H2 Database.

Then, click on the Generate button. When we click on the Generate button, it starts packing the project in a .zip(jdbctest-example) file and downloads the project. Then, Extract the Zip file. 

Then, import the project on your favourite IDE.

Final Project directory:


Complete 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 
   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>3.1.5</version>
      <relativePath/> <!-- lookup parent from dao -->
   </parent>
   <groupId>com.knf.dev.demo</groupId>
   <artifactId>jdbctest-example</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>jdbctest-example</name>
   <description>Demo project for Spring Boot</description>
   <properties>
      <java.version>17</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-jdbc</artifactId>
      </dependency>

      <dependency>
         <groupId>com.h2database</groupId>
         <artifactId>h2</artifactId>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
               <image>
                  <builder>paketobuildpacks/builder-jammy-base:latest</builder>
               </image>
            </configuration>
         </plugin>
      </plugins>
   </build>

</project>

spring-boot-starter-test starter will provide following libraries:

  • JUnit 
  • Spring Test & Spring Boot Test 
  • AssertJ
  • Hamcrest 
  • Mockito 
  • JSONassert 
  • JsonPath 
Spring Boot doesn’t require any special configuration for h2 database to work.

Create schema.sql

To generate a database schema at application start, the file schema.sql with the corresponding SQL commands for schema creation must be stored in the resources folder.
CREATE TABLE students (
  id INT AUTO_INCREMENT  PRIMARY KEY,
  name VARCHAR(250) NOT NULL,
  email VARCHAR(250) NOT NULL,
  age INT
);

Create test-student-data.sql

INSERT INTO students (id,name, email, age) VALUES
  (101,'Alpha', 'alpha@knf.com', 50),
  (102,'Beta', 'beta@knf.com', 40),
  (103,'Gama', 'gama@knf.com', 30),
  (104,'Pekka', 'pekka@knf.com', 20);
Later, as the part of testing we will use this file for loading data.

Create Model - Student.java

package com.knf.dev.demo.model;

public class Student {

    private Long id;

    private String name;

    private String email;

    private Integer age;

    public Student() {
    }

    public Student(Long id, String name, String email, Integer age) {
        this.id = id;
        this.name = name;
        this.email = email;
        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 String getEmail() {
        return email;
    }

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

    public Integer getAge() {
        return age;
    }

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


Create StudentDAO.java

package com.knf.dev.demo.dao;

import com.knf.dev.demo.model.Student;

import java.util.List;

public interface StudentDAO {

    List<Student> findByAgeGreaterThan(Integer age);

    Student findByName(String name);

    List<Student> findByAgeLessThan(Integer age);

}

  • findByAgeGreaterThan(): If we want to retrieve students whose age is greater than the given age.
  • findByName(): This method will get student entity by name.
  • findByAgeLessThan(): If we want to retrieve students whose age is less than the given age.


Create StudentDAOImpl.java

package com.knf.dev.demo.dao;


import com.knf.dev.demo.model.Student;
import org.springframework.jdbc.core.JdbcTemplate;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

//@Repository
public class StudentDAOImpl implements StudentDAO {

    private final JdbcTemplate jdbcTemplate;

    public StudentDAOImpl(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    @Override
    public List<Student> findByAgeGreaterThan(Integer age) {

        String sqlQuery = "select id, name, email, age from students where age > ?";

        return jdbcTemplate.
                query(sqlQuery, this::mapRowToUser,age);
    }

    @Override
    public Student findByName(String name) {

        String sqlQuery = "select id, name, email, age from students where name = ?";

        return jdbcTemplate.
                    queryForObject(sqlQuery,
                            this::mapRowToUser, name);

    }

    @Override
    public List<Student> findByAgeLessThan(Integer age) {

        String sqlQuery = "select id, name, email, age from students where age < ?";

        return jdbcTemplate.
                query(sqlQuery, this::mapRowToUser,age);
    }

    private Student mapRowToUser(ResultSet resultSet, int rowNum)
            throws SQLException {

        Student student = new Student(resultSet.getLong("id"),
                resultSet.getString("name"),
                resultSet.getString("email"),
                resultSet.getInt("age"));

        return student;
    }
}


JdbctestExampleApplication.java

package com.knf.dev.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class JdbctestExampleApplication {

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

}


Write unit test against H2 in-memory database

When using JUnit 4, this annotation should be used in combination with @RunWith(SpringRunner.class). But for this example  we are using JUnit 5, there’s no need to add the equivalent @ExtendWith(SpringExtension.class).

package com.knf.dev.demo;

import com.knf.dev.demo.model.Student;
import com.knf.dev.demo.dao.StudentDAO;
import com.knf.dev.demo.dao.StudentDAOImpl;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
import org.springframework.boot.test.autoconfigure.jdbc.JdbcTest;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.jdbc.Sql;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;

@JdbcTest
public class StudentDAOTests {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Test
    @Sql({"/test-student-data.sql"})
    void findByName_ReturnsTheStudent() {

        StudentDAO studentDAO = new StudentDAOImpl(jdbcTemplate);
        Student student = studentDAO.findByName("Alpha");

        assertThat(student).isNotNull();
        assertThat(student.getEmail()).isEqualTo("alpha@knf.com");
        assertThat(student.getName()).isEqualTo("Alpha");
        assertThat(student.getId()).isEqualTo(101);
        assertThat(student.getAge()).isEqualTo(50);
    }

    @Test
    @Sql({"/test-student-data.sql"})
    void findByAgeGreaterThan_ReturnsTheListStudents() {

        StudentDAO studentDAO = new StudentDAOImpl(jdbcTemplate);
        List<Student> students = studentDAO.findByAgeGreaterThan(29);

        //Convert list of students to list of id(Integer)
        List<Integer> ids = students.stream()
                .map(o -> o.getId().intValue())
                .collect(Collectors.toList());

        assertThat(students.size()).isEqualTo(3);
        assertThat(ids).hasSameElementsAs(Arrays.asList(103,102,101));
    }

    @Test
    @Sql({"/test-student-data.sql"})
    void findByAgeLessThan_ReturnsTheListStudents() {

        StudentDAO studentDAO = new StudentDAOImpl(jdbcTemplate);
        List<Student> students = studentDAO.findByAgeLessThan(31);

        //Convert list of students to list of id(Integer)
        List<Integer> ids = students.stream()
                .map(o -> o.getId().intValue())
                .collect(Collectors.toList());

        assertThat(students.size()).isEqualTo(2);
        assertThat(ids).hasSameElementsAs(Arrays.asList(104,103));
    }
}

  • The @Sql annotation executes SQL scripts and SQL statements using datasource for testing.
  • assertThat is used to check the specified value matches the expected value. It will accept the two parameters, the first contains the actual value, and the second will have the object matching the condition.


5. Run the test

Or you can run the test using following command: 

mvn  test -Dtest=StudentDAOTests

Popular posts from this blog

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

Example 1: Java 8 program to print odd numbers from a List   import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; /*Java 8 Program to find Odd Numbers from a List*/ public class DriverClass { public static void main( String [] args) { List < Integer > numbers = Arrays. asList( 1 , 4 , 8 , 40 , 11 , 22 , 33 , 99 ); List < Integer > oddNumbers = numbers.stream(). filter(o -> o % 2 != 0 ). collect(Collectors.toList()); System.out.println(oddNumbers); } } 1. Initialize List using Arrays.asList() method. Java's built-in Arrays.asList() method converts an array into a list. This method takes an array as an argument and returns a List object. 2.  Java List interface provides stream() method which returns a sequential Stream with list of Integer as its source. 3. The Java stream filter(...
Read more

Java Stream API - How to convert List of objects to another List of objects using Java streams?

Image
In this section, we will show you how to convert a List of objects to another List of objects in Java using the Java streams map(). The ‘map’ method maps each element to its corresponding result. Java Stream API   The Java Stream API provides a functional programming approach over the object oriented capabilities of Java. It is used for processing collections of objects. The Stream in Java can be defined as a sequence of elements from a source List, Set or Array. Most of the stream operations return a Stream. This avails engender a chain of stream operations(stream pipe-lining). The streams withal support the aggregate or terminal operations on the elements. for example, finding the sum or maximum element or finding the average etc...Stream operations can either be executed sequentially or parallel. when performed parallelly, it is called a parallel stream.   Stream map() Method   The Java 8 Stream map() is an intermediate operation. It converts Stream<obj1> to Str...
Read more

Registration and Login with Spring Boot + Spring Security + Thymeleaf

Image
In this section, we will learn how to create user registration and login using Spring boot, Spring security, Thymeleaf, JPA, and H2DB. The GitHub repository link is provided at the end of this tutorial. You can download the source code. Technologies used: Spring Boot 2.5.5  Spring Data JPA  Spring Security  Thymeleaf  Maven 3+  Java 17  H2 Database   User Interface User Registration Authentication Failed Authentication success Sign out Final Project Structure: Complete 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 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-pare...
Read more

Java, Spring Boot Mini Project - Library Management System - Download

Image
Hello everyone, Hope you are doing well. Here, we provide a Library Management System mini-project for beginners, it's free for download. Maybe you can build more on top of this project and create your own product, that's all about you. The source code download link is provided at the end of this post. 1. Benefit of this project You could cover the following technologies and features by learning and debugging this mini project. Java 17 Java Stream Java Lamda Expressions Java Records Functional programming Object-oriented programming var Keyword in Java Generics in Java Java Switch Spring boot 2.6.4 Spring Security Thymeleaf template engine OpenCSV Spring Data JPA Server Side Pagination H2 Database  Bootstrap HTML CSS and more... 2. Objective Of Spring Boot On Library Management System The main objective of this project is to manage the details of the books, author, category, and publisher. Only Admin/Librarian will manage all these activities. Also, they can export the data in ...
Read more

ReactJS, Spring Boot JWT Authentication Example

Image
In this tutorial, we’ll create a user registration & login example using ReactJS, Spring Boot, Spring Security, and JWT authentication. You could download the source code from our Github repository, the download link is provided at the end of this tutorial. Technologies used Backend Technologies: Java 17 Spring Boot 2.7.0 Spring Security Spring Data JPA JWT H2 Database Frontend Technologies: React 17.0.1 Axios 0.27.2 Redux 4.0.5 Bootstrap 4.5.2 ReactJS - SpringBoot - JWT - Flow Backend Project Directory: Frontend Project Directory: Following is the screenshot of our application - User Registration: User Signin: Profile View: Access Resource: We will build two projects:  1. Backend:   spring-boot-security-jwt 2. Frontend: react-redux-jwt Project 1: spring-boot-security-jwt 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"...
Read more

Top 5 Java ORM tools - 2024

Image
  The term ORM refers to object-relational mapping, which uses objects to adapt programming languages to database systems while allowing them to function with SQL and object-oriented programming ideas. Any kind of database management system that can accomplish object mapping to the table in the virtual system is suitable for the implementation of ORM. Java has a wide variety of ORM tools, some of which are mentioned below: 1. Hibernate Hibernate is a lightweight, open-source, non-invasive Java ORM (Object-Relational Mapping) framework that allows developers to create objects that function independently of database software and create persistence logic in any Java or JavaEE application. It offers an abstraction layer, so developers don't have to bother about implementations; Hibernate handles these tasks internally, such as connecting to databases and creating queries to carry out CRUD operations, among other things. Persistence logic development is done with it. Persistence logic r...
Read more

Java - Blowfish Encryption and decryption Example

Image
Blowfish is an encryption method developed by Bruce Schneier in 1993 as an alternative to the DES encryption method. It is significantly faster than DES and provides good encryption speed, although no effective cryptanalysis technique has been found to date. It is one of the first secure block ciphers that is not protected by any patents and is therefore freely available for anyone to use. This is a symmetric block cipher algorithm. Block size: 64 bits Key size: variable size from 32 to 448 bits number of subsections: 18 [P-array] number of rounds: 16 number of substitution blocks: 4 [each with 512 records of 32 bits each] develop  Example 1: Encryption and decryption using Blowfish import java.io.UnsupportedEncodingException; import java.nio.charset.Charset; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.util.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSiz...
Read more

Spring boot video streaming example-HTML5

Image
Hello everyone, Today we will learn how to stream MP4 video using Spring Boot and Spring Web Flux.  The Source code download link is provided at the end of this post. New, Quarkus Practice User Interface   Project Structure: G radle(build.gradle) plugins { id 'org.springframework.boot' version '2.5.4' id 'io.spring.dependency-management' version '1.0.11.RELEASE' id 'java' } group = 'com.knf.demo' version = '0.0.1-SNAPSHOT' sourceCompatibility = '11' repositories { mavenCentral() } dependencies { implementation 'org.springframework.boot:spring-boot-starter-webflux' testImplementation 'org.springframework.boot:spring-boot-starter-test' testImplementation 'io.projectreactor:reactor-test' } test { useJUnitPlatform() } Service (VideoStreamingService.java) package  com.knf.demo.service ; import org.springframework.beans.factory.annotation. Autowired ; import org.springframework...
Read more

Google Cloud Storage + Spring Boot - File Upload, Download, and Delete

Image
In this section, we will learn  how to  create a simple spring boot application to perform different file operations such as upload, download, list, and delete files from the Google Cloud Storage. 1.  A little bit of Background Google Cloud Storage Cloud Storage is a managed service for storing unstructured data. Store any amount of data and retrieve it as often as you like. More Info - click here! Spring Boot Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you can "just run".  More Info - click here! 2. Create a GCP Project First, Sign into the Google console at  https://console.cloud.google.com . You can create a new project by first selecting the project dropdown in the top left and selecting " New Project ". Next, specify your GCP  Project name  and  Project ID . Then  Click on the " CREATE " button. Copy " Project ID " and keep it for future purposes. 3. Create a Google Cloud Storage bucke...
Read more