I'm developing a Java SE 11 Maven project. In my project I have a folder called assets (it's a sibling of the src folder). This folder contains several folders and files. The whole folder has to be available at the application path - during development (in Netbeans) AND when it is deployed via an MSI package.
When running in the IDE, my assets live in <projectRoot>/assets, while my current working dir is <projectRoot>. And that's ok. I can access the assets folder via ./assets from my current working directory.
But when I deploy my application, the current working directory might be something else, but not the application folder. So accessing the assets folder via ./assets will fail.
What's the best approach in Java SE, to access a folder within the application's folder, independent of the current working directory?
Turning the assets into a resource folder is not an option, because the files must editable by the user. The assets folder has to reside directly in the file system.
If you put your files/resources inside your source folder, you can access them through ClassName.getResource() and ClassName.getResourceAsStream() methods.
use a config file or maven profiles (local and production)
in that config or profile define a folder where the files are
old anwser:
use Resources, the files in the jar (i assume your application is in a jar)
will be accessible using the
URL url = Main.class.getResource("filename")
or
Inputstream stream = Main.class.getResourceAsStream("filename")
replace 'Main' with your classname
https://docs.oracle.com/javase/8/docs/technotes/guides/lang/resources.html
https://www.tutorialspoint.com/java/lang/class_getresourceasstream.htm
In my web application I have to send email to set of predefined users like finance#xyz.example, so I wish to add that to a .properties file and access it when required. Is this a correct procedure, if so then where should I place this file? I am using Netbeans IDE which is having two separate folders for source and JSP files.
It's your choice. There are basically three ways in a Java web application archive (WAR):
1. Put it in classpath
So that you can load it by ClassLoader#getResourceAsStream() with a classpath-relative path:
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("foo.properties");
// ...
Properties properties = new Properties();
properties.load(input);
Here foo.properties is supposed to be placed in one of the roots which are covered by the default classpath of a webapp, e.g. webapp's /WEB-INF/lib and /WEB-INF/classes, server's /lib, or JDK/JRE's /lib. If the propertiesfile is webapp-specific, best is to place it in /WEB-INF/classes. If you're developing a standard WAR project in an IDE, drop it in src folder (the project's source folder). If you're using a Maven project, drop it in /main/resources folder.
You can alternatively also put it somewhere outside the default classpath and add its path to the classpath of the appserver. In for example Tomcat you can configure it as shared.loader property of Tomcat/conf/catalina.properties.
If you have placed the foo.properties it in a Java package structure like com.example, then you need to load it as below
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("com/example/foo.properties");
// ...
Note that this path of a context class loader should not start with a /. Only when you're using a "relative" class loader such as SomeClass.class.getClassLoader(), then you indeed need to start it with a /.
ClassLoader classLoader = getClass().getClassLoader();
InputStream input = classLoader.getResourceAsStream("/com/example/foo.properties");
// ...
However, the visibility of the properties file depends then on the class loader in question. It's only visible to the same class loader as the one which loaded the class. So, if the class is loaded by e.g. server common classloader instead of webapp classloader, and the properties file is inside webapp itself, then it's invisible. The context class loader is your safest bet so you can place the properties file "everywhere" in the classpath and/or you intend to be able to override a server-provided one from the webapp on.
2. Put it in webcontent
So that you can load it by ServletContext#getResourceAsStream() with a webcontent-relative path:
InputStream input = getServletContext().getResourceAsStream("/WEB-INF/foo.properties");
// ...
Note that I have demonstrated to place the file in /WEB-INF folder, otherwise it would have been public accessible by any webbrowser. Also note that the ServletContext is in any HttpServlet class just accessible by the inherited GenericServlet#getServletContext() and in Filter by FilterConfig#getServletContext(). In case you're not in a servlet class, it's usually just injectable via #Inject.
3. Put it in local disk file system
So that you can load it the usual java.io way with an absolute local disk file system path:
InputStream input = new FileInputStream("/absolute/path/to/foo.properties");
// ...
Note the importance of using an absolute path. Relative local disk file system paths are an absolute no-go in a Java EE web application. See also the first "See also" link below.
Which to choose?
Just weigh the advantages/disadvantages in your own opinion of maintainability.
If the properties files are "static" and never needs to change during runtime, then you could keep them in the WAR.
If you prefer being able to edit properties files from outside the web application without the need to rebuild and redeploy the WAR every time, then put it in the classpath outside the project (if necessary add the directory to the classpath).
If you prefer being able to edit properties files programmatically from inside the web application using Properties#store() method, put it outside the web application. As the Properties#store() requires a Writer, you can't go around using a disk file system path. That path can in turn be passed to the web application as a VM argument or system property. As a precaution, never use getRealPath(). All changes in deploy folder will get lost on a redeploy for the simple reason that the changes are not reflected back in original WAR file.
See also:
getResourceAsStream() vs FileInputStream
Adding a directory to tomcat classpath
Accessing properties file in a JSF application programmatically
Word of warning: if you put config files in your WEB-INF/classes folder, and your IDE, say Eclipse, does a clean/rebuild, it will nuke your conf files unless they were in the Java source directory. BalusC's great answer alludes to that in option 1 but I wanted to add emphasis.
I learned the hard way that if you "copy" a web project in Eclipse, it does a clean/rebuild from any source folders. In my case I had added a "linked source dir" from our POJO java library, it would compile to the WEB-INF/classes folder. Doing a clean/rebuild in that project (not the web app project) caused the same problem.
I thought about putting my confs in the POJO src folder, but these confs are all for 3rd party libs (like Quartz or URLRewrite) that are in the WEB-INF/lib folder, so that didn't make sense. I plan to test putting it in the web projects "src" folder when i get around to it, but that folder is currently empty and having conf files in it seems inelegant.
So I vote for putting conf files in WEB-INF/commonConfFolder/filename.properties, next to the classes folder, which is Balus option 2.
Ex: In web.xml file the tag
<context-param>
<param-name>chatpropertyfile</param-name>
<!-- Name of the chat properties file. It contains the name and description of rooms.-->
<param-value>chat.properties</param-value>
</context-param>
And chat.properties you can declare your properties like this
For Ex :
Jsp = Discussion about JSP can be made here.
Java = Talk about java and related technologies like J2EE.
ASP = Discuss about Active Server Pages related technologies like VBScript and JScript etc.
Web_Designing = Any discussion related to HTML, JavaScript, DHTML etc.
StartUp = Startup chat room. Chatter is added to this after he logs in.
It just needs to be in the classpath (aka make sure it ends up under /WEB-INF/classes in the .war as part of the build).
You can you with your source folder so whenever you build, those files are automatically copied to the classes directory.
Instead of using properties file, use XML file.
If the data is too small, you can even use web.xml for accessing the properties.
Please note that any of these approach will require app server restart for changes to be reflected.
Assume your code is looking for the file say app.properties. Copy this file to any dir and add this dir to classpath, by creating a setenv.sh in the bin dir of tomcat.
In your setenv.sh of tomcat( if this file is not existing, create one , tomcat will load this setenv.sh file.
#!/bin/sh
CLASSPATH="$CLASSPATH:/home/user/config_my_prod/"
You should not have your properties files in ./webapps//WEB-INF/classes/app.properties
Tomcat class loader will override the with the one from WEB-INF/classes/
A good read:
https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html
I need to include a file into my war. Currently, in non Web applications the file in question is added to the top level directory, the class that uses it searches for this file at this level.
I need to use Maven, or somehow in the web app to include this file at the top level of the war file. My current directory structure is as follows:
Project
|--Src/Main/Java
|--Package
|--X.class
|--WebContent
|-- META-INF
|-- resources
|-- WEB-INF
|--POM.XML
|--FileToInclude.Properties
The diagram above shows the X.class in my spring application, it uses the FileToInclude.properties file, and it must be at the top level. Any ideas?
This structure would work on a normal project, just not when its a web application and the certain files get built.
thanks
You can include that file in any directory that is part of the classpath.
If you need to include it inside the war you need to add in the WEB-INF/classes directory.
If you like to add it externally you can add it to any directory that is part of the classpath when your war is loaded by the application server. Generally is possible to specify to the application server which directories use as part of the classpath
I have one java web project folder and it contains folders like /conf, /css, /html, /js, /jsp and /WEB-INF.
/conf folder contains vestweb.cfg, *.css, *.html, *.js, *.jsp files.
/WEB-INF has /src folder and contains java source files(not able to find project to import.).
I could not find any root files(.war) in those folders.
How can I configure this folders to run the application?
If I understand you correctly, what you need to do is package the folder structure into a deployable package (exploded or compressed).
Compile the java source from "WEB-INF/src" folder and copy the class files to "WEB-INF/classes" folder
You can rename the root folder as "[YOUR_PROJECT].war" or you can compress it to a .WAR file
Deploy the package into any web-application server
Access your files from browser
Question 1: May I ask what is the difference between deploying a java webapp with it's WAR file vs just copy/pasting the build folder into tomcat webapp folder?
Question 2: Somehow I am told to deploy my project just by renaming my /build/web folder to /build/, then copy and paste this folder into tomcat/webapp folder. Tomcat did serve the web app and I could access it via url. But the problem is that I suspect my System variables were not set. I start up a servlet and put this code in this init(ServletConfig config) method:
System.setProperty("LogPath","D:/Test/logs");
And doing this in my log4j.properties
log4j.appender.file.FILE=${LogPath}/wrapper.log
wrapper.log is not found in the designated directory but a stdout.log is found in tomcat/logs folder.
I am sure the init() method was fired because I have a quartz scheduler there. I am suspecting that my System.setProperty was not set. Any hint?
Update: With all the same source code, I have no problem if I am deploying with a WAR file. The ${LogPath} in log4j.properties work as expected.
Let me answer you the first question.
WAR file is a zip archive with different name. When you deploy this file to the Tomcat server, it unpacks this file to its folder as you would do it by copy-paste. If you are just developing your own project in your own environment and you don't want to distribute it, you don't need to create a war file. But if you want to distribute this project, I recommend you to create a war file. One file is easier to be sent.
Read more on Wikipedia http://en.wikipedia.org/wiki/WAR_%28file_format%29