I have a spring boot application that currently runs in embedded Tomcat. I have a file, states.csv, that I want to parse on startup and seed my states database table (I tried via liquibase but that refuses to work).
I put the file in resources/main/ and that appears to work fine. My question is, if I decided against embedded Tomcat in the future (say moving to AWS or a regular Tomcat), is this still the best location to keep files for use?
I don't want to code myself into a corner if there is a better way to do this.
This depends entirely on how you're reading the file. As long as you're grabbing it out of the classpath, you should be fine. (And I've run single-jar applications on both basic AWS VMs and Cloud Foundry on EC2 with no difficulty at all.)
Related
In our Linux environment applications are restarted periodically (the reasons aren't important here). It would be convenient for us to deploy new versions of an application by copying the application Spring Boot jar on top of the existing (old) jar thereby overwriting it and then simply wait for the application to restart (that is, the JVM running the application to restart).
However, this seems to not work. We get different kinds of errors - sometimes the app just hangs, sometimes we get a ClassNotFoundException. It's as if Spring Boot (or something inside Spring Boot) reopens the jar and expects it to be the same one it was when the application was originally started.
We had a look through Spring's common application properties, but didn't see anything appropriate. Is there a way to make this work? When we were using WAR files we configured the servlet container to unpack the WAR file and run from the unpacked version. Can we do something similar with Spring Boot?
First of all the errors you are experiencing can come from multiple sources. Usually replacing the file from a process is not a big problem as the whole file is loaded into memory before execution. Java is a little bit different, because the actual process that is running is the JVM and it only loads the jar file from disk. The JVM loads classes only on demand, this means if there was any class that was not loaded before it will try to load it and most likely fail, if the jar file is different. In the case of spring boot there are also other resources (such as HTML files) inside the jar file that are dynamically loaded.
You mentioned you are using a linux environment. If you can just replace your startup with a script you can just copy the jar and start it from the copied location:
#!/bin/bash
JAR_NAME="spring-boot.jar"
NEW_JAR_NAME=".$JAR_NAME" # Use an appropriate name here
cp $JAR_NAME $NEW_JAR_NAME
java -jar $NEW_JAR_NAME
rm $NEW_JAR_NAME
Now every time you start the application a copy is being made and started from there. You can replace the original jar and on the next restart the new application will load.
You coud also use rsync instead of cp to avoid copying the same jar twice, if the application is restarted multiple times without changing the jar.
It would be convenient for us to deploy new versions of an application
by copying the Spring Boot jar on top of the existing (old) jar and
then simply wait for the application to restart
Why would you do such a thing to yourself? You are trying solve a usecase that's against best practices, sound like asking for trouble just to avoid an app restart. When you are doing a deployment, you need to make sure the deployment went through, otherwise how will you troubleshoot if something goes wrong in your application, you will have one more variable in hand when you troubleshoot, i,e the uncertainty of current version of the code.
If you are having downtime while deploying (I am assuming thats why you want to limit the restarts), why don't you bring up another instance with the newer version of code and once its healthy shutdown the old one
I've made a spring boot project called student-management using spring MVC, Thymeleaf, spring data JPA and MySql. When I run it locally on localhost:8081 it works perfectly. I made CRUD operations so I see all the changes in database when changed on the website and vice versa.
Now, I need to get my website "out there" for others to see, specifically a company. I'm new to Spring boot and everything that goes with it but I don't understand how to deploy my rather simple website so the company can access it by not using localhost.
This is my project_hierarchy. As you can see it's quite simple.
This is my StudentController.java. I've used #Controller and maybe I should've used #RestController. If so, how do I change it to #RestController so that my website still works.
My thymeleaf html files students.html edit_students.html create_student.html
Deploying remotely means choosing a host (e.g. AWS), setting up infrastructure, deploying your executable JAR with dependencies, and running it on a server.
You'll need to set up a separate MySQL instance and connect your app to it. That means you'll set up the database server, create the database and schema, and start it up before your app starts.
You should be thinking about security and who should be able to access your app and data. Most developers who have only deployed locally tend to put off those considerations. I'd urge you to think about them sooner.
If your purpose is to provide access inside your company, only to employees, perhaps you'd be better off making your local machine available to others on the network OR choose a server that's already on your company network. You'll have to work with others to make that happen.
I have an Eclipse RCP(E4) application, which I can start without any problem. Now I decide to connect it to my Spring-Boot embedded Tomcat-server. The Spring-Boot-container runs an H2 as an in memory DB. Running Spring-Boot as "Java Application", I access the data in the DB via a rest-service over the browser.
The problem is, I actually want to embed the Spring-Boot part in my RCP-application. So once I start the application it will start my embedded Sring-Boot tomcat and I can run my CRUD-operations directly from the RCP-UI.
Has anyone got experience dealing with Eclipse-RCP running with Spring-Boot?
P.S: I chose explicitly to not put any code hier, because I don't have any code problem yet. The applications run separately well. I just haven't no clue how to relate them.
Our application are built on Spring boot, the app will be packaged to a war file and ran with java -jar xx.war -Dspring.profile=xxx. Generally the latest war package will served by a static web server like nginx.
Now we want to know if we can add auto-update for the application.
I have googled, and people suggested to use the Application server which support hot deployment, however we use spring boot as shown above.
I have thought to start a new thread once my application started, then check update and download the latest package. But I have to terminate the current application to start the new one since they use the same port, and if close the current app, the update thread will be terminated too.
So how to you handle this problem?
In my opinion that should be managed by some higher order dev-ops level orchestration system not by either the app nor its container. The decision to replace an app should not be at the dev-ops level and not the app level
One major advantage of spring-boot is the inversion of the traditional application-web-container to web-app model. As such the web container is usually (and best practice with Spring boot) built within the app itself. Hence it is fully self contained and crucially immutable. It therefore should not be the role of the app-web-container/web-app to replace either part-of or all-of itself.
Of course you can do whatever you like but you might find that the solution is not easy because it is not convention to do it in this way.
Could be a silly question, but...
I have a Spring-based WAR application that runs 80% of the installations on Tomcat and the rest 20% on WebSphere.
I need to simply get the path of the folder where Spring's MultipartFilter (using Commons multipart resolver) stores files being uploaded. I have never set it manually, and it actually belongs to the Catalina work directory as I found out in my Tomcat installations.
For the moment, I just need to get that path. I have control of my application so no one is going to change it without notice.
I would like to know if there is a server-agnostic way to know where my Spring-based application is going to store Multipart files.
E.g. from this question I can see I can use catalina.base, but in Tomcat... not in JBoss or WebSphere. It could cost me a couple of if/else statements...
Spring tries to do it already when no default value is set
WebUtils.getTempDir(servletContext)
Which simply does:
return ((File)servletContext.getAttribute("javax.servlet.context.tempdir"));
So simply if no one overrides that location in the filter properties (and that is my case) I can rely on the default.
More in general, one may have to inspect the instance of DiskItemFileFactory to get the path to the repository