How To Become Surround Variables Inward Java- Event Tutorial
Environment variables inwards Java
There are 2 ways to teach surroundings variable inwards Java, yesteryear using System properties or yesteryear using System.getEnv(). System properties provides exclusively express ready of predefined surroundings variables similar java.classpath, for retrieving Java Classpath or java.username to teach User Id which is used to run Java programme etc but a to a greater extent than robust in addition to platform independent agency of getting surroundings variable inwards Java program on the other manus System.getEnv() method render access to all surroundings variables within Java programme but dependent champaign to innovate platform dependency if programme relies on a item surroundings variable. System.getEnv() is overloaded method inwards Java API in addition to if invoked without parameter it returns an unmodifiable String map which contains all surroundings variables in addition to at that spot values available to this Java procedure spell System.getEnv(String name) returns value of surroundings variable if exists or null. In our before posts nosotros convey seen How to teach electrical current directory inwards Java in addition to How to run trounce ascendency from Java program in addition to inwards this Java tutorial nosotros volition come across how to access surroundings variable inwards Java.
How to teach surroundings variables inwards Java - Example
String map of all surroundings variables spell System.getEnv(String name) only render value of named surroundings variable similar JAVA_HOME volition render PATH of your JDK installation directory.
/**
* Java programme to demonstrate How to teach value of surroundings variables inwards Java.
* Don't confuse betwixt System holding in addition to Environment variable in addition to at that spot is separate
* agency to teach value of System holding than surroundings variable inwards Java, every bit shown inwards this
* example.
*
* @author Javin Paul
*/
public class EnvironmentVariableDemo {
public static void main(String args[]){
//getting username using System.getProperty inwards Java
String user = System.getProperty("user.name") ;
System.out.println("Username using organization property: " + user);
//getting username every bit surroundings variable inwards java, exclusively plant inwards windows
String userWindows = System.getenv("USERNAME");
System.out.println("Username using surroundings variable inwards windows : " + userWindows);
//name in addition to value of all surroundings variable inwards Java program
Map<String, String> env = System.getenv();
for (String envName : env.keySet()) {
System.out.format("%s=%s%n", envName, env.get(envName));
}
}
}
Output:
Username using organization property: harry
Username using surroundings variable inwards windows : harry
USERPROFILE=C:\Documents in addition to Settings\harry
JAVA_HOME=C:\Program Files\Java\jdk1.6.0_20\
TEMP=C:\DOCUME 1\harry\LOCALS 1\Temp
* Java programme to demonstrate How to teach value of surroundings variables inwards Java.
* Don't confuse betwixt System holding in addition to Environment variable in addition to at that spot is separate
* agency to teach value of System holding than surroundings variable inwards Java, every bit shown inwards this
* example.
*
* @author Javin Paul
*/
public class EnvironmentVariableDemo {
public static void main(String args[]){
//getting username using System.getProperty inwards Java
String user = System.getProperty("user.name") ;
System.out.println("Username using organization property: " + user);
//getting username every bit surroundings variable inwards java, exclusively plant inwards windows
String userWindows = System.getenv("USERNAME");
System.out.println("Username using surroundings variable inwards windows : " + userWindows);
//name in addition to value of all surroundings variable inwards Java program
Map<String, String> env = System.getenv();
for (String envName : env.keySet()) {
System.out.format("%s=%s%n", envName, env.get(envName));
}
}
}
Output:
Username using organization property: harry
Username using surroundings variable inwards windows : harry
USERPROFILE=C:\Documents in addition to Settings\harry
JAVA_HOME=C:\Program Files\Java\jdk1.6.0_20\
TEMP=C:\DOCUME 1\harry\LOCALS 1\Temp
Getting surroundings variable inwards Java – Things to remember
Java is platform independent linguistic communication but at that spot are many things which tin make a Java programme platform dependent e.g. using a native library. Since surroundings variables too vary from ane platform to unopen to other e.g. from windows to Unix you lot request to last chip careful spell take away accessing surroundings variable within Java program. Here are few points which is worth noting :
1) Use organization properties if value of surroundings variable is available via system property e.g. Username which is available using "user.name" organization property. If you lot access it using surroundings variable take away you lot may request to inquire for unlike variable every bit it may last unlike inwards Windows e.g. USERNAME in addition to Unix every bit USER.
2) Environment variables are case sensitive inwards Unix spell instance insensitive inwards Windows then relying on that tin ane time again brand your Java programme platform dependent.
3) System.getEnv() was deprecated inwards unloosen JDK 1.3 inwards back upwards of using System.getProperty() but reinstated ane time again inwards JDK 1.5.
That's all on how to teach surroundings variable inwards Java. Though you lot convey convenient method similar System.getEnv() which tin render value of surroundings variable, its amend to purpose System.getProperty() to teach that value inwards a platform independent way, if that surroundings variable is available every bit organization holding inwards Java.
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