Refreshing static content with Spring MVC and Boot

Question

I'm evaluating Spring MVC & Boot and AngularJs for building web applications. I've run into the problem that when I make modifications to my static content (html, js, css), I have to restart the application every time. I hope there is a some way of solving that because restarting the whole application for static content changes is not efficient. Every other web app framework I've tried allows updating static content files on the fly(even just Spring MVC and plain old WAR application).

I've setup my project from "Building a RESTful Web Service with Spring Boot Actuator" guide (http://spring.io/guides/gs/actuator-service/). Basically it uses Spring Boot and MVC controllers to create a REST service. In addition, I've used "Consuming a RESTful Web Service with AngularJS" guide (http://spring.io/guides/gs/consuming-rest-angularjs/) to build a frontend with AngularJS. It creates a web page that displays the response from the REST service. The only change I've made is that the requests are made to my application instead of "http://rest-service.guides.spring.io/greeting". My static content is stored in "src/main/resources/public" folder. This setup works correctly except it doesn't reload static content.

Answer 1

A recap of the original problem

I've run into the problem that when I make modifications to my static content (html, js, css), I have to restart the application every time

I had the same problem and finally solved it by adding

<configuration>
    <addResources>true</addResources>
</configuration>

to spring-boot-maven-plugin in the pom.xml I got confused by this spring-boot-devtools thing, but it had no effect whatever I did.

My static content is stored in "src/main/resources/public" folder.

Your path is just fine. src/main/resources/static is also fine.

Answer 2

Ah ... I came across this issue too.

Instead of putting your static content in the classpath src/main/resources/public folder, put them in src/main/webapp, the same as you would any other Java web app. The embedded Tomcat will automatically reload them whenever they change.

As mentioned in the comments, the default configuration will not include the resources that are in src\main\webapp. To get around this issue, you can just add the following to your pom.xml <build> node:

<plugin>
    <artifactId>maven-resources-plugin</artifactId>
    <version>2.6</version>
    <executions>
        <execution>
            <id>copy-resources</id>
            <phase>validate</phase>
            <goals>
                <goal>copy-resources</goal>
            </goals>
            <configuration>
                <outputDirectory>${basedir}/target/classes/static</outputDirectory>
                <resources>
                    <resource>
                        <directory>src/main/webapp</directory>
                        <filtering>true</filtering>
                    </resource>
                </resources>
            </configuration>
        </execution>
    </executions>
</plugin>

By using the resources plugin, you are able to do your local development by running the executable JAR:

java -jar target/.jar

While that is running you can use Chrome Dev Tools or whatever IDE you like for modifying the files, without restarts. However, whenever you run your build, then the package generated will include all of the files under src\main\webapp in src\main\resources\static.

Answer 3

The docs say "all modern IDEs allow reloading of static resources and usually also hot-swapping of Java class changes" (https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/html/howto.html#howto-hotswapping). It's true. Eclipse does it more or less by default, and I'm not an IntelliJ user, but from what I understand you can configure it to build automatically as well.

Answer 4

A colleague and I came across this issue as well. We found the answer in the IntelliJ documentation...

On the main menu, choose Run | Reload Changed Classes

Answer 5

My solution (written in Kotlin but is quite obvious):

@Controller
class WebController : WebMvcConfigurerAdapter() {

    override fun addResourceHandlers(registry: ResourceHandlerRegistry) {
        System.getProperty("resources.local.path")?.let {
            registry.addResourceHandler("/**").addResourceLocations(it)
        }
    }
...
}

Main idea is you can add your own resource handler conditionally. E.g. if some system property is set (resources.local.path) then add resource location with value from the property. Then you set this property in development with some reasonable value like '-Dresources.local.path=file:/Users/andrey/Projects/gsp-test/src/main/resources/static/'.

Do not forget trailing slash.

Answer 6

I am using 1.5.8.RELEASE.

It instantly updates my changes especially static files or jsp files.

If you are using Maven. You need to add this in pom.xml

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
    </dependency>

And you have to start Spring Boot with this:

mvn clean spring-boot:run

Full example and more detail here https://www.surasint.com/spring-boot-with-auto-update-changed-files-example/

Answer 7

@eigil metioned addResources config for maven build. I'm using spring-boot-gradle-plugin in a gradle build, and I found this Spring Boot github issue , and the Spring Boot doc mentioned this option too. Just add this directive to build.gradle and run Gradle task bootRun, then resource file refreshes immediately when saved. FYI.

Answer 8

I had the same issue , the solution proposed here seems logical and worked for me in breif : 1- ctrl+shift+A 2- search for registry 3- in the opened dialogue search for "compiler.automake.allow.when.app.running" and check it http://garywaddell.com/2015/11/20/spring-boot-intellij-idea-not-reloading-static-content/

Answer 9

For eclipse you have to activate the Project -> "Build Automatically" option as a minimum configuration.

Answer 10

What I ended up using was Browsersync with grunt. browsersync and grunt watches your static resources on disk and updates the browser when you edit the files. It acts as a kind of proxy. This way you can see changes in UI immediately without building or restarting anything.

Grunt, browsersync, spring boot and angularjs are configured for you if you use JHipster which I used to setup my project.

Granted this requires a lot more tools than just an IDE and is a lot more complicated so I wouldn't recommend this for every project.

Answer 11

spring-boot-devtools is not the solution to "hot deploy" of edited static htm/js

I configured a web facet inside intellij so that when I use it to edit html/js file inside resources/static, intellij then knows to copy the updated file to ./target and the spring boot application I have launched inside the automatically displays that content

see https://www.jetbrains.com/help/idea/2016.2/configuring-static-content-resources.html

Answer 12

The Java version of @viator 's answer:

@Configuration
class WebMvcConfigurer extends WebMvcConfigurerAdapter {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/dist/*.js").addResourceLocations(
            "file:src/main/typescript/dist/"
        );
    }
}

Answer 13

You can do it by just adding one more dependency

you Gradle

compile group: 'org.springframework.boot', name: 'spring-boot-devtools', version: '1.3.0.RELEASE'

In you Pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <version>1.3.0.RELEASE</version>
</dependency>

Answer 14

You have two possebilities how to serve static webcontent

1. From the classpath (per default src/main/resources/static or src/main/resources/public or META-INF/resources/)
2. From the file system (per default src/main/webapp)

If you pick solution 1) - you can safely copy the jar around as the static web content is within that jar. If you want that the server picks up changes, you need to do (auto)hotswapping.

If you pick solution 2) - everything will work out of the box, every change will be automatically picked up. HOWEVER - if you copy the final jar to a different location - things will stop working. That is unless you specify an absolute path in application.properties. For example:

spring.resources.static-locations=file:///C:/myspringbootapp/src/main/webapp

So solution 2) is easier but less portable. Solution 1) is portable but more difficult to use(ide config).

Answer 15

For Spring Boot 2+ with gradle Kotlin dsl:

tasks.bootRun {
    sourceResources(sourceSets.getAt(SourceSet.MAIN_SOURCE_SET_NAME))
}

thanks to @briskr's answer for the gradle dsl version :)

Answer 16

I had the same problem with live reloading of static contents in my SpringBoot porject: Now from various solutions posted in StackOverflow, I am able to get the solution. Following are the tools I used for development: IntelliJ Idea & Google Chrome in Ubuntu 18.04 I did the following:

1. Kept the templates folder in resourses folder itself. (Some solutions I found it to be kept in webapp folder under the main, but I did not get the result)
2. Add this configuration

    <addResources>true</addResources>
    </configuration>

to spring-maven-plugin in your POM file.

3.Please don't forget to add this dependency to POM file

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

4. Add the Live Reload extension to your web browser.

5. Restart the server using ' mvn clean spring-boot:run ' (only then the changes will be reflected in the build). During server startup you can see the message Live Server started at ....

6. Load the page using localhost:8080/... and click the LiveReload extension to connect it with the server.

7. Make any change to your static HTML file in the resources/ templates folder. Save it and check the webbrowser again, it will be reflected there...

Answer 17

This is my solution using Spring Boot 3.1.2, Spring Boot Web Starter, and Spring Boot Devtools.

Set the following properties in application-dev.properties:

spring.web.resources.static-locations=file:src/main/resources/static/
spring.devtools.restart.additional-paths=file:src/main/resources/static/

Notice that this is a development-only set up because in production static content will be served from the classpath.

What it does:

• Devtools is instructed to restart the service whenever there are changes in the static directory. This will trigger a live reload. It pairs great with live-reload browser extensions.
• Static resources are served from the file system instead of the classpath. It allows serving updated static files without needing to rebuild the project. Thus, eliminating the need to configure your IDE to rebuild on every save which may be a little slow, depending on the project.

I use this setup for a web project built with Vite, (vite build --watch) dumping all output in src/main/resources/static/ and Spring Boot Devtools picking up the changes almost immediately.