Is there any development mode in Spring like in Struts. In Struts if we set dev mode to true all the configuration files are loaded in every request. However now when I'm developing in Spring MVC, I have to restart server after every change. Or is there some other method by which I can force reload.
No there is no such configuration for Spring MVC. But it is a good idea for an feature request.
Answering both of your questions and keeping it short.
No, there is nothing like a devmode in Spring framework so you can throw it out of your head.
Yes, you could skip reloading by using some bytecode manipulation techniques. You can use either:
external tool (like JRebel or Javaleon)
server with hot deployment (like Jetty)
IDE (some IDEs offer such functionalities as well)
Hope that helps.
What change you refer to? Template changes?
Even with struts, JSP and velocity templates shouldn't reload the servlet container. Only Java classes would do that.
I have written a blog post Spring-mvc + Velocity + DCEVM about how to use Spring + Velocity + Dynamic Code Evolution VM (DCEVM) in order to not restart the server when developing:
Yes: If you are using Tomcat or a derivative (VMWare vFabric tc Server), you can configure application reload behavior (hot deploy). This allows changes to say a method to be reloaded without restart. The key is to set:
Publishing set to Automatically publish when resources change
Your web module set to Auto Reload disabled.
VMWare vFabric tc Server 2.6+ (packaged with STS 2.9+) provides two options:
Java Agent-based reloading
JMX-based reloading
If you are using Spring Boot, then all you need to do is add the dependency devtools to your project. This allow you to have your application deployed each time you modify a classpath file.
maven
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
Gradle:
dependencies {
compileOnly("org.springframework.boot:spring-boot-devtools")
}
Spring docs: Spring boot devtools
Related
I've started learning Spring Boot coming from a NodeJS/Express background and I'm wondering what's the difference between the server that we create ourselves in an express app that listens on a certain port, and the Tomcat server in a spring application also called a container ? Why can't we do the same in a spring boot application where we create the server ourselves ?
const app = express();
app.listen(3000, () => console.log("Server listening on port 3000"));
Welcome to the Spring Ecosystem. We hope you enjoy your stay!
My first bit of advice, forget everything you know about Express because Spring is very different. I have not used Express in a while, but I remember it had a very programmatic approach. While that is possible in Spring, the most popular approach is declarative with annotations. Or, if you are old and like old technology, you can configure everything with XML.
What's Tomcat? Tomcat is a implementation of various Jakarta EE (formally Java EE) specifications. Depending on the Spring Boot version, you may see packages that start with jakarta or javax. Tomcat implements, Jakarta Servlet, Server Pages, Expression Language, WebSocket, Annotations, and Authentications. You can read more about each specification here. Note: Spring Boot by itself does not necessary use all of these modules and mostly Spring has many abstraction layers on top of them anyway, so you rarely will work with Tomcat directly. Specifically, spring-boot-starter-tomcat is the Spring module that uses Tomcat, and is most often included as a transitive dependency through spring-boot-starter-web.
Now, to answer your question...
Spring Boot Web configures Tomcat for you. You can definitely override this behavior! One basic way is through configuration properties. Anything under server.tomcat. A good IDE should autocomplete and show you the options. You can also change the address and port of the Tomcat server with server.address and server.port. Another popular property developers change is server.error.whitelabel.enabled. They set it to false and provide their own error page. Here is a great example. By the way, Baeldung offers a lot of free Spring tutorials and guides. It is a great place to get started. They also offer paid courses with certifications.
FYI, you do not have to use Tomcat. Read more here.
I setup Camunda in my Spring 3 project (Tomcat server) using this guide. I embedded the workflow engine in my project.
However, I cannot access the cockpit when I go to the url http://localhost:8080/camunda/app/. I get a 404 error.
I see that there is a dependency to be added in case of Spring boot according to this guide
But I see no such dependencies available for Spring. Do we not get access to webapps while integrating Camunda with Spring?
Also asked this question in the camunda form: https://forum.camunda.org/t/integrating-camunda-webapps-in-spring-framework/27661
You'll need the following dependency.
<dependency>
<groupId>org.camunda.bpm.webapp</groupId>
<artifactId>camunda-webapp-webjar</artifactId>
</dependency>
Then ensure you have the required configurations. Refer the spring boot auto configuration set up here and the web app initialiser here.
I have a web app built with Java, Spring MVC, and JDBC. The result is a WAR file.
To run it, the user has to install Java 8 JDK and Tomcat, and deploy the WAR file to the Tomcat server.
It would be great if they could just download the one file run it as a standalone application.
That is, run "the WAR file" and just browse to http://localhost:8080/myapp
Also, on Windows it would be great it was setup as a Server (like Tomcat is when installed with the installer).
Is there any way to do this? Maybe with Spring Boot or something new like that?
Yep, Spring boot is the way to go.
It allows you to build an executable Jar with all dependencies and a Tomcat (by default, can be changed) embedded.
But users will still need to download a JRE to execute the Jar, and a database if it's required, but you can use en embedded database like H2, HSQLDB..., depends what is your needs.
Yes . you can use spring boot to achieve your results. Kindly refer the below link for sample code
https://mkyong.com/spring-boot/spring-boot-hello-world-example-jsp/
You can use embedded jetty server using maven but that would require you to setup few things your app and may have align your existing app, please check this article for more information.
Jetty is similar to tomcat server in terms of running spring application, there are not much difference in terms of development. Tomcat is just more famous.
Other option as others said, is to migrate your app to spring boot which would be easy if you already have app written in spring (But that depends how much code you have and how much time you have)
I have developed a micro service (Spring Boot REST service, deployed as executable JAR) to track all activities from third party projects as my requirement and its working now.
Currently it's working apart of some projects, and now I have updated service with some additional features.
But I can't move it to live server without restarting the existing service as it is deployed as jar. I'm afraid to restart my service, restart may be leads to lose data of integrated projects.
What improvements can I make in my architecture to solve my problem?
What about JRebel plugin. It worked perfectly for me, but, unfortunately, it's not a free app. Like alternative, (i used this approach with Spring MVC, with Spring Boot it could be otherwise), I set up a soft link in work directory on a compiled path in JBoss (in my case it was dir with name target and *.class and *.jar files). As for me, the first solution with JRebel is the most appropriate for you.
Finally got a solution as commented by #Gimby .
We can do it by deploying multiple instances of services and it bound to a service registry ,Here i achieved it by using eureka as registry service and also used zuul as proxy .
I want to use RestTemplate/TestRestTemplate by including the artifact in a SpringBoot application
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
But this automatically starts Tomcat or Jetty. Is there a way to turn it off, or by not including the above artifact. TestRestTemplate is in the boot artifact, but not the base RestTemplate.
Spring Boot is not going to start a web container if it's not present. spring-web does not provide any embedded container. You may want to analyse the dependencies of your project (try mvn dependency:tree).
If you want to make sure a web server is not started in your spring boot application, you can set the following configuration key
spring.main.web-application-type=none
Or you can use the SpringApplicationBuilder
new SpringApplicationBuilder(YourApp.class)
.web(WebApplicationType.NONE).run(args);
Since Spring Boot 2.0.0 this property is deprecated and following is the new way:
spring.main.web-application-type=none
This change is because Spring Boot the support for reactive server.
You can just close the app according to https://spring.io/guides/gs/async-method/. Although this still stars Tomcat, but will stop the app at the end without keeping the tread running.
SpringApplication.run(MyApp.class, args).close();