Kickstart Spring Boot: Build Your First Web Service in Minutes

Overview

Spring Boot simplifies Spring development by providing auto‑configuration, an embedded servlet container and a convention‑over‑configuration approach. This guide shows how to create a minimal Spring Boot project with Maven, add the web starter, implement a “Hello World” REST endpoint, and verify it with a unit test using MockMvc.

Prerequisites

Java 8 (or Java 7+) installed.

Maven 3.x.

Spring Boot 1.3.2 or later.

Project generation

Use Spring Initializr (http://start.spring.io) to generate a Maven project. Select the desired Group, Artifact, and Spring Boot version, then download and extract the ZIP.

Directory layout

src/main/java

– contains the application entry class (e.g., Chapter1Application). src/main/resources – holds application.properties and other resources. src/test/java – contains test classes (e.g., Chapter1ApplicationTests).

Configure Maven dependencies

Add the core starter, test starter and web starter to pom.xml:

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

Implement the Hello World controller

Create a package (e.g., com.didispace.web) and add the following class:

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String index() {
        return "Hello World";
    }
}

Run the application (the generated Chapter1Application contains the main method). Access http://localhost:8080/hello in a browser; the response body should be Hello World .

Write a unit test with MockMvc

Create a test class under src/test/java:

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = MockServletContext.class)
@WebAppConfiguration
public class Chapter1ApplicationTests {

    private MockMvc mvc;

    @Before
    public void setUp() throws Exception {
        mvc = MockMvcBuilders.standaloneSetup(new HelloController()).build();
    }

    @Test
    public void getHello() throws Exception {
        mvc.perform(MockMvcRequestBuilders.get("/hello")
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("Hello World")));
    }
}

Import the static matchers used in the test:

import static org.hamcrest.Matchers.equalTo;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

Build and run

From the project root execute mvn clean package to compile and package the application.

Run the executable JAR with java -jar target/artifactId-0.0.1-SNAPSHOT.jar (replace artifactId with your project name).

The embedded Tomcat starts on port 8080; the endpoint and unit test can be exercised as described above.

Key points

Spring Boot’s auto‑configuration eliminates XML and boilerplate code.

The spring-boot-starter-web starter brings in Spring MVC and an embedded servlet container.

MockMvc enables fast, isolated controller tests without starting the full server.