How does Eclipse IDE resolve File/Resource location? - java

My question is expressed in terms of these
two Images.
In the first one, configuration.configure() method of hibernate loads the
file from src folder as indicated by red arrows
While in this second image,
it is shown that PropertyConfigurator.configure() method of Log4j loads the file from
root folder of Project as indicated by the red arrows again
In both projects, this and only this setup works and no alternate setup works.
Thanks for help.

Eclipse isn't doing anything, it's all the JVM. the results would be the same if you used the command line or another IDE.
The different programs load configuration diferently in your 2 examples.
Hibernate loads config files as a resource which looks for a file with that path on your class path which is why it can be in src.
sourcode of Hibernate's Configuration#configure(String)
Log4j uses the String as a path to open a FileInputStream. Since you give a relative path, it looks for a file relative the root of your project
sourcecode of log4j PropetyConfigruator#configure(String)

load hibernate.cfg.xml
configuration.configure(hibernate.cfg.xml) means your hibernate configuration file “hibernate.cfg.xml” is at the root of your project classpath.Even if you don't pass the configuration file name in the configure() method, it will work, but in that case name should be hibernate.cfg.xml.
If you want to place this configuration file into a different directory then you need do like below
new Configuration().configure("/com/config/hibernate.cfg.xml")
load log4j.properties
Loading log4j.properties also works in the similar way.
If you want to put your log4j.properties in to com-->config source folder you can do like below
PropertyConfigurator.configure("classpath:com/config/log4j.properties");

Related

Reading application.properties file in ResourceBundle class [duplicate]

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

Overriding a resource contained in a jar file

I am running a tool (a virtual globe) through code from a jar file. The code reads a resource (an XML file) to provide some configuration options, using syntax like this, in a method of class Config:
URL localURL = Config.class.getResource("Config.xml");
I would like to provide my own Config.xml file with settings that override those in the file contained in the jar file.
I am not clear about how I can do this. I understand that the getResource() method explores the classpath to find the resource. So I thought of this:
- putting a copy of the file with my own settings in a specific directory
- putting this directory in front of the classpath
But to no avail: the getResource() still always loads the resource from the jar file.
I must be missing something ...
I tried removing the Config.xml file from the application jar. That fails: the application fails because getResource() returns null. It seems to me like
Config.class.getResource("Config.xml")
only looks for resources inside the jar file that contains class Config, whereas I thought it was looking in the classpath.
OK, got it. The issue is this: my Config class is really in a package, i.e. vis.globe.Config.java, so getResource("Config.Xxml") really looks for a file called vis.globe.Config.xml.
Therefore, with a classpath such as "../config:../jar/appl.jar", it will look for file Config.xml, not in ../config, but in ../config/vis/globe.
So the solution was to create a sub-directory structure in ../config that reflects the fully qualified name of class Config.java, i.e.
../config/vis/globe/Config.xml
You could always look to do something programmatically. So for example you would first search for a file named UserConfig.xml and if it was not found fall back on the file named Config.xml which would be found in the jar file.

cloudbees & ESAPI - how do I point to the ESAPI directory?

I'm using ESAPI for my project, and added the ESAPI configuration directory to src/main/resources so it is copied to my WAR file (I downloaded the WAR from cloudbees, I can see it was put in WEB-INF/classes/esapi/ directory)
Locally, I just point to where the directory is and all works fine, but on cloudbees it just doesn't work for me.
In order to access its properties, ESAPI project tries all kinds of stuff, including checking the org.owasp.esapi.resources system property, so I've added the following code to cloudbees-web.xml:
<sysprop name="org.owasp.esapi.resources" value="WEB-INF/classes/esapi/" />
and I can see that the system property value is found because of the following error in the logs:
Not found in 'org.owasp.esapi.resources' directory or file not readable: /var/genapp/apps/akld3873/WEB-INF/classes/esapi/ESAPI.properties
so it finds the system property (because the path is like I've specified), but when it looks for the actual directory and files in it, I guess the directory is either not there or not readable.
Do I need to move it somewhere else? Inside the WEB-INF directory maybe? Is the setting not right? I've read that others solved similar issues by building a JAR just for this directory, but this doesn't seem like a good solution, there must be a simple setup that will work for cloudbees.
Design for ESAPI lib to require a directory access to configuration is not very flexible.
A general purpose option is to use ServletContext.getRealPath to resolve the absolute filesystem path to this directory and pass it to ESAPI.
Another option is for you to have some init code to copy WEB-INF/classes/esapi content in a temporary directory (using java.io.temp system property to point to the currently configured temp dir for your app) and point ESAPI lib to this path.
Ok so after searching and testing, I finally figured it out.
Cloudbees deploys your web app to the following directory:
staxcat/install/webapp.war/
notice that this is a relative path, with prefix of this path attached it looks something like this:
/var/genapp/apps/xxxxxxxx/staxcat/install/webapp.war/WEB-INF/esapi/ESAPI.properties
so, in order to get ESAPI to work, I had to set the following in cloudbees-web.xml:
<sysprop name="org.owasp.esapi.resources" value="staxcat/install/webapp.war/WEB-INF/esapi" />
this will enable ESAPI to find the directory if in your project it is located under:
src/main/webapp/WEB-INF/esapi
and you should get the following log line:
Found in 'org.owasp.esapi.resources' directory: /var/genapp/apps/xxxxxxxxx/staxcat/install/webapp.war/WEB-INF/esapi/ESAPI.properties

Java (maven web app), getting full file path for file in resources folder?

I'm working with a project that is setup using the standard Maven directory structure so I have a folder called "resources" and within this I have made a folder called "fonts" and then put a file in it. I need to pass in the full String file path (of a file that is located, within my project structure, at resources/fonts/somefont.ttf) to an object I am using, from a 3rd party library, as below, I have searched on this for a while but have become a bit confused as to the proper way to do this. I have tried as below but it isn't able to find it. I looked at using ResourceBundle but that seemed to involve making an actual File object when I just need the path to pass into a method like the one below (don't have the actual method call in front of me so just giving an example from my memory):
FontFactory.somemethod("resources/fonts/somefont.ttf");
I had thought there was a way, with a project with standard Maven directory structure to get a file from the resource folder without having to use the full relative path from the class / package. Any advice on this is greatly appreciated.
I don't want to use a hard-coded path since different developers who work on the project have different setups and I want to include this as part of the project so that they get it directly when they checkout the project source.
This is for a web application (Struts 1.3 app) and when I look into the exploded WAR file (which I am running the project off of through Tomcat), the file is at:
<Exploded war dir>/resources/fonts/somefont.ttf
Code:
import java.io.File;
import org.springframework.core.io.*;
public String getFontFilePath(String classpathRelativePath) {
Resource rsrc = new ClassPathResource(classpathRelativePath);
return rsrc.getFile().getAbsolutePath();
}
In your case, classpathRelativePath would be something like "/resources/fonts/somefont.ttf".
You can use the below mentioned to get the path of the file:
String fileName = "/filename.extension"; //use forward slash to recognize your file
String path = this.getClass().getResource(fileName).toString();
use/pass the path to your methods.
If your resources directory is in the root of your war, that means resources/fonts/somefont.ttf would be a "virtual path" where that file is available. You can get the "real path"--the absolute file system path--from the ServletContext. Note (in the docs) that this only works if the WAR is exploded. If your container runs the app from the war file without expanding it, this method won't work.
You can look up the answer to the question on similar lines which I had
Loading XML Files during Maven Test run
The answer given by BobG should work. Though you need to keep in mind that path for the resource file is relative to path of the current class. Both resources and java source files are in classpath

"log4j:WARN Please initialize the log4j system properly" error

I have a web application, in which one of the JSPs contain:
PropertyConfigurator.configure(System.getenv("MY_HOME") + "/cfg/log4j.properties");
I double-checked that MY_HOME is setup
The Tomcat web server says:
log4j:WARN No appenders could be found for logger (com.mycompany.data.JobData).
log4j:WARN Please initialize the log4j system properly.
The same setup works fine in one of the other servers.
Any hints?
The problem is that no logs are created
Not related to your answer, but this helps too.
If it's a web application, the easiest way is to make sure that your log4j.properties is situated in WEB-INF/classes folder in your WAR file. When your application will be deployed, log4J will be configured.
The PropertyConfigurator must be called before anything in your system attempts to log to avoid this warning. You may find setting the log4j configuration on the command line more reliable.
Or you could ignore the warning. ;)
BTW: You don't want to call this method too often, ideally only once.
You can try this, its helps to me.
http://www.log4j.ru/articles/HelloWorld.html
I was able to find the solution to this problem running a Eclipse Dynamic Web Project in Apache Tomcat 6. Bascially, you need to load the log4j properties file out of your context.
Two basic steps
(1) Get the log4j.properties file into the "class directory" of the war file.
(2) Read the log4j properties file out of the current context. I found the best way to do this is to access the current thread's context and work from there.
For the first step above, alter the Eclipse build process to add an additional directory that will eventually load into the WEB-INF/classes directory in the war file. Specifically....
(1) In Eclipse, right click your project in the project explorer, select 'New'->'Folder'. You can name the folder anything, but the standard in this case is 'resources'. The new folder should appear at the root level of your project.
(2) Move the log4j.properties file into this new folder.
(3) Right click the project again, and select 'Build-Path'->'Configure Build Path'. Select the 'Sources' tab. Click the 'Add Folder' button. Browse to find your new folder you created in step (1) above. Select 'OK'.
(4) Once back to the eclipse Project Explorer view, note that the folder has now moved to the 'Java Resources' area (ie it's no longer at the root due to eclipse presentation abstraction).
(5) Clean build your project.
(6) To validate that the .properties file now exists in WEB-INF/classes in your war file, export a war file to an easy location (right click Project -> Export -> War file) and checkout the contents. Note that the log4j.properties file now appears in the WEB-INF/classes.
Now for the second step above, accessing the context to read the file. Add the following code where attempting to read the file. Note that this reads this out of the war file context, so this 'should' work as the war file moves from server to server.
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
PropertyConfigurator.configure(classLoader.getResourceAsStream("log4j.properties") );

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