I want to set the log4j configuration file path/other folder paths that can be used across other class files, without hard-coding the folder path.
Rightnow, I have set the variables as Environment variable. But It can only be modified if I launch Eclipse. How do I set this variable in such away that anyone (doesn't want to launch Eclipse) can modify it, from outside. Also, it will be used in test configurations. So it's better to not hard-code it and have all the file paths etc. easy to refactor.
final static String log4jpath = System.getenv("LOG4J_PATH");
Paraphrasing a comment:
[How to get value from] outside of the Java program such as a separate file, that contains all other filepaths?
That is called a configuration file.
It is often a properties file, similar to a Log4j configuration file, but it can be any types of file, e.g. XML, JSON, YAML, ...
To identify a single such file, you can use:
An environment variable (like you are right now)
A system property (more common)
A specifically named file in the current directory
...
The entries in that file will identify all the values you really want.
For example, Spring, which is a populate Java framework, will look for configuration values in many places. See 24. Externalized Configuration for full detail, but here is a summary of the most common ones:
Command line arguments, e.g. java -jar MyApp.jar --foo=bar
Java System properties, e.g. set using -Dfoo=bar on the command-line
OS environment variables, e.g. SET foo=bar (Windows) or export foo=bar (Linux)
Application properties outside of your packaged jar, i.e. relative to current directory.
Name and location can be overridden on command-line.
config/application.properties
config/application.yaml
application.properties
application.yaml
Soni, If you want to put the log4j configuration file in one place so that everybody can access. Follow the steps.
Create a project with some name and inside src/main/resources folder keep the log4j configuration file.
Create a jar file which must contain this log4j configuration file.
Use this created jar file wherever it is required. Log4j will automatically use the configuration for desired logging. If you want, you can distribute this jar file to anybody who wants to use it.
The above option is if you do not want to change the configuration file.
Now if there is a situation where someone wants to modify the configuration file.
In this case, simply put the configuration in any project classpath, means inside resource folder. As long as log4j jar files are there in the classpath and configuration files. It will log everything.
However, if you want, you can extend the functionality of Log4j by passing configuration as an object. You can refer below the link to access pro grammatically.
https://howtodoinjava.com/log4j/how-to-programmatically-configure-appenders-in-log4j/
I have added all file and folder paths inside the properties file (example config.properties) and then used it inside the testsetup method by InputStream input = new FileInputStream("Path to//config.properties");
Properties prop = new Properties();
prop.load(input);
System.setProperty("log4j2.configurationFile", prop.getProperty("log4j.path"));
this way, all files/folder paths can be modifies from outside and there's no need to set environment variable from inside the project.
Related
I have a properties file in one of the .jar of my maven dependencies. I would like to override the values in my application so I created a file with the same name and the same package, but the values from the jar file are still being used. If I delete the properties file from the jar, the values of the file in my application are used. How can I always use the properties from my application instead of the .jar ?
As long as code takes your property file from class path it depends how your class path configured.
If you externalized your file out of any jar files - Try to put path to directory where your actual file located upfront of any other jar files in your java command -cp parameter.
If you keep your file inside your own jar file, in classpath - your jar file must be before that dependency jar file with default properties file.
Still those are not good solutions (sometime it is hard to control which path JVM will use first).
So, try to find documentation about your dependency jar - it may have a property to point from where and which properties file to use.
You can use Maven Resource Plugin and parametrize your configuration file so you can pass the parameters as arguments through command line
Use the properties resource in the jar as template, initial file for the properties file you will use:
Path propertiesFile = Paths.get(System.getProperty("user.home"),
".myapp/config.properties");
Files.createDirectories(propertiesFile.getParent());
if (!Files.exists(propertiesFile)) {
Files.copy(getResourceAsStrem("/config.properties"), propertiesFile);
}
Properties props = new Properties();
props.load(new FileInputStream(propertiesFile.toString());
How about this ?
rename the properties file with overridden values,
like this _override.properties (if the actual file is
called original.properties.
Now, in your code, read a system property, called 'toOverrideProps', if true, to load the overridden properties file
when running your program, you can set this property using the -Dprop=value method
This way, you have a choice on startup, to use the actual properties file or the overridden one, without conflict.
I need to be able to read in a property file, that lives outside of my war. My problem is that a need a solution that will allow me to tell my war file where my property file is located. Can this be done through bashrc variables and windows env variables?
I need to do this because I need to be able to drop the property file in different locations that could be away from the war file.
I am struggling to come up with a solution.
This will very much depends what the property file is for. Some libraries will have have the possibility of setting it on the command-line and others will allow you to explicitly load them in code.
In case of the latter, System.getProperties() can prove helpful, since it allows you to read properties passed to the JVM using the '-D' flag. For example
java -jar -Dfilelocation="yourfilelocation" yourapp.jar
would populate the system property 'filelocation' with the string 'yourfilelocation'. This could then be used in your code to load the property file (or whatever you want to do with it).
Since you are running inside some sort of application server, there are different ways you can accomblish this. For jetty you can put them in start.ini (or simply pass them on the command-line when you start jetty)
where tomcat uses an enviroment variable called JAVA_OPTS, so
JAVA_OPTS='-Dfilelocation=yourfilelocation' start.sh
would set the system property when you start tomcat.
one way is to provide specific location by passing java argument or setting up environment varialble and read it from app to determine the location
and as a fallback (default) app should be announcing to look at
${user.home}/appname/some.peroperties
You could defines a list of possible directories ... and try to read each one ...
I have a solution that read a property file in the file system using a default directory structure.
Eg: c:\properties\code-suit\prd\application.properties
Where:
code-suit is a variable defined by application name;
prd is a environment that I will use
Good luck
I am having issues with properties file when I try to make my standalone Java aplication a runnable jar.
I have 2 properties file, depending upon the machine where its running one gets initialized.
Inside eclipse it was working fine. I was using:
Properties configProps = new Properties();
....
if(machine1)
....
configProps.load(Config.class.getResourceAsStream("machine1.properties"));
else
configProps.load(Config.class.getResourceAsStream("machine2.properties"));
It was working as Config.java and properties were in the same package.
On top of that I have log4j properties located on the root of the project.
That is also not working whne i made Jar.
How to handle the current sutuation.I know putting properties file outside jar is good idea.
How do I accomplish this.
Please help.
Putting the properties file outside of the jar is only a good idea if you need to write to that property file (it's for configuration). Given your naming, I assume it is for configuration.
For reading only, your method is fine if the properties file is properly being packaged in the Jar. Is it? Have you peaked at the contents using jar tf MyJar.jar? Does it show your properties file at the correct path?
Where to store configuration files is a broader issue. Here's a good SO article that examines a few aspects of it (namely where to put it): What is the proper way to store app's conf data in Java?
It seems to me you want to choose a location (see the above article). Once you've done that, the first time the application is run you should load the default properties from your Jar file as you are trying to do, then immediately save them to the location you've chosen. Then, and afterwards, read from and write to that location instead. You will need to use a FileInputStream/FileOutputStream.
Try adding a manifest to your JAR's META-INF with Class-Path set appropriately.
Currently i have placed the Displaytag.properties in 'src' directory, and it is working fine. Is it posssible to have this file on some different location like src/comp/bre/sub/config ?
From the docs for the DisplayTag library:
For the whole web application, create
a custom properties file named
"displaytag.properties" and place it
in the application classpath.
Displaytag will use the locale of the
request object to determine the locale
of the property file to use; if the
key required does not exist in the
specified file, the key will be loaded
from a more general property file.
So in your case make sure your build scripts (or IDE) copy your displaytag.properties file from src/comp/bre/sub/config the onto the classpath.
In an IDE this is normally as simple as specifying that a particular directory contains source code. In ANT just make sure the displaytag.properties file ends up in your /WEB-INF/classes.
Find the code which loads this properties file and add the new path. You can also place it in a folder yourProject/src/resources/ and add it to the classpath. Therefore, your properties file will be placed in the binary folder once the code will be compiled.
What is the best way to store and load application level properties in Java.
Is there anything simulare to .net where I would just put something in the app.config
<appSettings>
<add key="emailAddress" value="me#example.com" />
</appSettings>
And then retrieve it like this:
string AdminEmail = ConfigurationManager.AppSettings["emailAddress"];
Do I have to load properties files into file streams and such? seems like unnecessary work.
I have tried this:
Properties props = new Properties();
FileInputStream fis = new FileInputStream("myProps.properties");
props.load(fis);
fis.close();
But this is give me a java.io.FileNotFoundException exception. Where does the properties file need to go to in relation to the class?
The Preferences API provides this functionality. It has many warts, but if you are looking to do this in an OS-agnostic fashion, this is the only way to accomplish this using the standard Java runtime libraries. You can of course always write your own OS-specific code to meet your needs. Yes, you can write simple code to load a properties file, but the location of that file can become a problem across multiple operating systems. I assume since you are writing a desktop app in Java, you care about OS portability. Otherwise Java might not be the best choice for a desktop app.
If you use a FileInputStream like that, your path is relative to the current directory of the OS, which usually is the startup directory.
If you instead use the Java built in resources mechanism (as described in the API, getResourceAsStream() et al), the path will be relative to the location of your class. With this approach you can also load resources from within jars and even over networks (for Applets for instance). The concept which is used is a sort of virtual filesystem, which is called the 'classpath' in Java jargon. There is a devx article covering it a litte more in detail.
In short, this sort of code works well:
Properties prop = new Properties();
//with properties in the same dir as current class
prop.load(getClass().getResourceAsStream("my.properties"));
//with properties in the root dir of your jar, or in base of classpath
prop.load(getClass().getResourceAsStream("/my.properties"));
You will need to add error handling...
Typically it will attempt to load from the application's current directory, which can vary depending on how you run it. You should be able to determine this at runtime by doing:
String currentFolder = System.getProperty("user.dir");
The file path it would be looking for in that case is relative to where you started your java application from. This is not where the main class is or the jar file but where you called Java from. If you are starting your application with a script that calls Java, then it is that directory.
Say for example, you application is bundled in a jar file 'app.jar'. Put 'myProps.properties' in the same directory and run 'java -jar app.jar' from that directory. It should find your properties file that way.
You can use Properties with a ResourceBundle. I use this in a application to store labels, buttons and messages in different languages
First you create a properties file, like test.properties. It´s a text file and inside it you put your information like this:
propertyname=value
In your case
emailAddress=me#example.com
email2=blablabla#example.com
and so on...
To get this properties in the code, create a ResourceBundle object with the name of your property file to call the properties.
ResourceBundle rb = ResourceBundle.getBundle("test");
To get an specific value from a properties file, just call the ResourceBundle
String value = rb.getString("emailAddress");
This way, the String named value contains the value of the property named "emailAddress", located in the test.properties file
String value2 = rb.getString("email2");
Likewise, the String named value2 contains the value of the property named "email2", located in the test.properties file
When you do not specify an absolute path, the one chosen is the current one.
It's not exactly what you asked, but if you want to use XML files as configuration, you could have a look at Apache Commons Configuration