> Markdown version of [Use Flow with Spring](https://vaadin.com/docs/v10/flow/spring/tutorial-spring-basic). Section index: [llms.txt](https://vaadin.com/docs/v10/flow/llms.txt)

# Use Flow with Spring

The `vaadin-spring` add-on allows you to use Flow with Spring in two ways: as a Spring Boot application and as a Spring Web application.

## <a id="spring-boot"></a>Spring Boot

The easiest way to use Spring is the Spring Boot application. To use the add-on, you only need to write one very simple class.

> **Note:** Please refer to the [Spring Boot](https://projects.spring.io/spring-boot/) project and its [documentation page](https://spring.io/docs) for information about Spring Boot.

> **Note:** There is another section [Use Flow with Spring MVC](https://vaadin.com/docs/v10/flow/spring/tutorial-spring-basic-mvc.md) in the tutorial which describes how to write pure Spring Web application without Spring Boot.

```java
@SpringBootApplication
public class ExampleServletInitializer extends SpringBootServletInitializer {

}
```

> **Note:** This code looks like magic and you may wonder why it works. The `@SpringBootApplication` annotation makes all the job for you under the hood.

Thanks to Spring Boot auto-configuration you only need the `vaadin-spring` add-on in your classpath and no Flow classes are needed in the class declaration. For `vaadin-platform` user, what you need to do is adding the `vaadin-bom` dependency to the `dependencyManagement` section in your `pom.xml`:

```xml
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-bom</artifactId>
            <version>${vaadin.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>com.vaadin</groupId>
        <artifactId>vaadin-spring-boot-starter</artifactId>
        <version>${vaadin.version}</version>
    </dependency>

    <!-- Spring -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>${spring-boot.version}</version>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
```

> **Note:** You can see the exclusion in the `spring-boot-starter-web` declaration. It’s not relevant for this example but if you want to run your application as a deployable WAR then this helps you avoid classpath collisions.

> **Note:** The `vaadin-spring` add-on doesn’t declare compile dependency to Spring Boot (it doesn’t appear transitively) so you should declare it by yourself. This is done to be able to use the add-on without Spring Boot.

Of course you need at least one Flow related class in your application to be able to handle URLs. The minimal code would be:

```java
@Route("")
public class HelloComponent extends Div {
    public HelloComponent(){
        setText("Hello world!");
    }
}
```

With the [ExampleServletInitializer](#example-servlet) you can deploy the application as a WAR to a web server. Spring Boot lets you speed up the development process and run the Spring Boot application as a plain Java Application. For this you need to add a main method with the following content:

```java
@SpringBootApplication
public class ExampleServletInitializer extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(ExampleServletInitializer.class, args);
    }
}
```

No need to do anything in addition to that. Once you start this Java application, Spring Boot will start its embedded web server and everything will work in the same way.

> **Note:** You should remove exclusion from the `spring-boot-starter-web` dependency in the `pom.xml` snippet above.

### <a id="note"></a>Note

Due to a bug when using `vaadin-upload-flow` component and use root mapping, then you need to disable the spring boot multipart upload by adding to `application.properties` the property `spring.servlet.multipart.enabled = false`.

This is already set in the spring starter, to follow the state of the problem see [vaadin/spring#381](https://github.com/vaadin/spring/issues/381)