{"id":124031,"date":"2024-06-27T12:12:00","date_gmt":"2024-06-27T09:12:00","guid":{"rendered":"https:\/\/www.javacodegeeks.com\/?p=124031"},"modified":"2024-06-27T11:22:26","modified_gmt":"2024-06-27T08:22:26","slug":"spring-boot-mvc-rest-controller-example-unit-tests","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/spring-boot-mvc-rest-controller-example-unit-tests.html","title":{"rendered":"Spring Boot MVC REST Controller Example & Unit Tests"},"content":{"rendered":"

In modern web development, REST APIs are essential for enabling communication between different systems and platforms. The Spring Framework, particularly Spring Boot, provides robust support for building RESTful web services, simplifying the development process through various annotations and tools. One such powerful annotation is @RestController<\/code>, which is used in Spring MVC to create RESTful API controllers. Let us delve into understanding a Spring Boot REST controller example to illustrate how to build a RESTful web service using Spring Boot.<\/p>\n

<\/a>1. What is @RestController annotation?<\/h2>\n

The @RestController<\/code> annotation in Spring Boot is a specialized version of the @Controller<\/code> annotation. It is typically used in web applications to handle RESTful web services. When a class is annotated with @RestController<\/code>, it serves as a convenience annotation that combines @Controller<\/code> and @ResponseBody<\/code>. This means that the methods in the class will return data directly in the response body, rather than rendering a view. It is particularly useful for creating RESTful APIs, as it simplifies the development process by eliminating the need for explicit @ResponseBody<\/code> annotations on each method. Overall, @RestController<\/code> streamlines the development of RESTful web services by providing a clear and concise way to define controllers that return JSON or XML responses.<\/p>\n

<\/a>2. Setting up a database on Docker<\/h2>\n

Usually, setting up the database is a tedious step but with Docker<\/a>, it is a simple process. You can watch the video available at this link<\/a> to understand the Docker installation on Windows OS. Once done open the terminal and trigger the below command to set and run postgresql.<\/p>\n

\n-- Remember to change the password --\ndocker run -d -p 5432:5432 -e POSTGRES_PASSWORD= --name postgres postgres\n\n-- command to stop the Postgres docker container --\ndocker stop postgres\n\n-- command to remove the Postgres docker container --\ndocker rm postgres\n<\/pre>\n
Remember to enter the password of your choice. If everything goes well the postgresql database server will be up and running on a port number \u2013 5432<\/code> and you can connect with the Dbeaver<\/a> GUI tool for connecting to the server.<\/p>\n
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Fig. 1. Postgres on Docker<\/figcaption><\/figure>\n<\/div>\n
2.1 Setting up pre-requisite data<\/h2>\n
To proceed further with the tutorial we will set up the required mock data in the postgresql.<\/p>\n
\ndrop database mydatabase;\n\ncreate database mydatabase;\n\ndrop table books;\n\ncreate table books (\n    id bigserial primary key,\n    title varchar(255) not null,\n    author varchar(255) not null,\n    price double precision not null\n);\n\ninsert into books (title, author, price) values ('the great gatsby', 'f. scott fitzgerald', 10.99);\ninsert into books (title, author, price) values ('1984', 'george orwell', 8.99);\ninsert into books (title, author, price) values ('to kill a mockingbird', 'harper lee', 12.50);\ninsert into books (title, author, price) values ('pride and prejudice', 'jane austen', 7.95);\ninsert into books (title, author, price) values ('the catcher in the rye', 'j.d. salinger', 9.99);\n\nselect * from books;\n<\/pre>\n
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Fig. 2: Sample data<\/figcaption><\/figure>\n<\/div>\n
<\/a>3. Code Example<\/h2>\n
3.1 Dependencies<\/h3>\n
Add the following dependencies to your build.gradle<\/code> file or if you have created a spring project from start.spring.io<\/a> this won\u2019t be necessary as the file will be automatically populated with the dependencies information.<\/p>\n
plugins {\n    id 'java'\n    id 'org.springframework.boot' version '3.3.0'\n    id 'io.spring.dependency-management' version '1.1.5'\n}\n\ngroup = 'jcg'\nversion = '0.0.1-SNAPSHOT'\n\njava {\n    toolchain {\n        languageVersion = JavaLanguageVersion.of(17)\n    }\n}\n\nrepositories {\n    mavenCentral()\n}\n\ndependencies {\n    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'\n    implementation 'org.springframework.boot:spring-boot-starter-validation'\n    implementation 'org.springframework.boot:spring-boot-starter-web'\n    runtimeOnly 'org.postgresql:postgresql'\n    testImplementation 'org.springframework.boot:spring-boot-starter-test'\n    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'\n}\n\ntasks.named('test') {\n    useJUnitPlatform()\n}\n<\/pre>\n
3.2 Configure application and database properties<\/h3>\n
Add the following properties to the application.properties<\/code> file present in the resources<\/code> folder.<\/p>\n
# application name\nspring.application.name=springjpademo\n\n# database properties\nspring.datasource.url=jdbc:postgresql:\/\/localhost:5432\/mydatabase\nspring.datasource.username=postgres\nspring.datasource.password=somepostgrespassword\n\n# application properties\nserver.port=9090\nspring.main.banner-mode=off\nspring.main.log-startup-info=false\n<\/pre>\n
The properties file defines:<\/p>\n