Command line arguments in java

I am trying to set command line arguments in a Netbeans 7.1 Java project on Windows 7 64 bit. Netbeans is not passing the arguments I give it. I go to Project --> Properties --> Run --> and type the arguments next to "Arguments" however the arguments are not passed to the program. How do I pass them? I am guessing that you are running the file using Run | Run File (or shift-F6) rather than Run | Run Main Project. The NetBeans 7.1 help file (F1 is your friend!) states for the Arguments parameter: Add arguments to pass to the main class during application execution. Note that arguments cannot be passed to individual files. I verified this with a little snippet of code: public class Junk I set Run -> Arguments to x y z. When I ran the file by itself I got no output. When I ran the project the output was: arg -> x arg -> y arg -> z • Create the Java code that can receive an argument as a command line argument. class TestCode • Run the program without arguments (press F6). • In the Output window, at the bottom, click the double yellow arrow (or the yellow button) to open a Run dialog. • If the argument you need to pass is testArgument, then here in this window pass the argument as application.args=testArgument. This will give the output as follows in the same Output window: first argument is: testArgument For Maven, the instructions are similar, but change the exec.args property instead: exec.args=-classpath %classpath package.ClassName PARAM1 PARAM2 PARAM3 Note: Use single qu...

• • • • • There are several ways to parse options in Java. My favorite is the commons-cli for short. Installing commons-cli If you're using a project management system like pom.xml or a configuration screen in Eclipse or NetBeans). If you're managing libraries manually, you can download commons-cli-X.Y.jar (where X and Y are the latest version numbers.) Add that JAR to your project, either manually or in your IDE, and then you can use it in your code. Importing a library into your Java code To use the commons-cli library in your code, you must import it. For this simple option parsing example, you can populate a file called Main.java with the standard minimal code: package com.opensource.myoptparser; import org.apache.commons.cli.*; public class Main Using Java and options Options allow users to modify how commands work. There are many ways to parse options when using Java, and the commons-cli is a robust and flexible open source solution. Give it a try in your next Java project.

The command-line arguments in Java allow us to pass arguments during the execution of the program. As the name suggests arguments are passed through the command line. Example: Command-Line Arguments class Main Let's try to run this program using the command line. 1. To compile the code javac Main.java 2. To run the code java Main Now suppose we want to pass some arguments while running the program, we can pass the arguments after the class name. For example, java Main apple ball cat Here apple, ball, and cat are arguments passed to the program through the command line. Now, we will get the following output. Command-Line arguments are Apple Ball Cat In the above program, the main() method includes an array of strings named args as its parameter. public static void main(String[] args) Let's try to run the program through the command line. // compile the code javac Main.java // run the code java Main 11 23 Here 11 and 23 are command-line arguments. Now, we will get the following output. Arguments in integer form 11 23 In the above example, notice the line int argument = Intege.parseInt(str); Here, the parseInt() method of the Integer class converts the string argument into an integer. Similarly, we can use the parseDouble() and parseFloat() method to convert the string into double and float respectively. Note: If the arguments cannot be converted into the specified numeric value then an exception named NumberFormatException occurs.

Check these out: • • Or roll your own: • For instance, this is how you use commons-cli to parse 2 string arguments: import org.apache.commons.cli.*; public class Main usage from command line: $> java -jar target/my-utility.jar -i asd Missing required option: o usage: utility-name -i,--input input file path -o,--output output file @RemkoPopma your picocli library looks just great and thank you for doing it, really. But I consider what you are doing here and in other posts (edit accepted answers and promote your library at the top of it without even disclosing it's an edit not from post's original author and it's your lib) a horrible horrible abuse of your moderation powers. Flagging this to other mods. I have been trying to maintain a • Airline • Active Fork: • argparse4j • argparser • args4j • clajr • cli-parser • CmdLn • Commandline • DocOpt.java • dolphin getopt • DPML CLI (Jakarta Commons CLI2 fork) • Dr. Matthias Laux • Jakarta Commons CLI • jargo • jargp • jargs • java-getopt • jbock • JCLAP • jcmdline • jcommander • jcommando • jewelcli (written by me) • JOpt simple • jsap • naturalcli • Object Mentor CLI article (more about refactoring and TDD) • parse-cmd • ritopt • Rop • TE-Code Command • picocli has ANSI colorized usage help and autocomplete Most of the projects listed are essentially abandonware. After going through the list I'd say the big hitters, that are actively maintained and popular, seem to commons-cli, jcommander, args4j, jopt-simple and picocli. Apo...

A Java application can accept any number of arguments from the command line. This allows the user to specify configuration information when the application is launched. The user enters command-line arguments when invoking the application and specifies them after the name of the class to be run. For example, suppose a Java application called Sort sorts lines in a file. To sort the data in a file named friends.txt, a user would enter: java Sort friends.txt When an application is launched, the runtime system passes the command-line arguments to the application's main method via an array of Strings. In the previous example, the command-line arguments passed to the Sort application in an array that contains a single String: "friends.txt". Echoing Command-Line Arguments The Echo example displays each of its command-line arguments on a line by itself: java Echo Drink Hot Java Drink Hot Java Note that the application displays each word — Drink, Hot, and Java— on a line by itself. This is because the space character separates command-line arguments. To have Drink, Hot, and Java interpreted as a single argument, the user would join them by enclosing them within quotation marks. java Echo "Drink Hot Java" Drink Hot Java Parsing Numeric Command-Line Arguments If an application needs to support a numeric command-line argument, it must convert a String argument that represents a number, such as "34", to a numeric value. Here is a code snippet that converts a command-line argument to an ...

When passing a -D parameter in Java, what is the proper way of writing the command-line and then accessing it from code? For example, I have tried writing something like this... if (System.getProperty("test").equalsIgnoreCase("true")) And then calling it like this... java -jar myApplication.jar -Dtest="true" But I receive a NullPointerException. What am I doing wrong? I suspect the problem is that you've put the "-D" after the -jar. Try this: java -Dtest="true" -jar myApplication.jar From the command line help: java [-options] -jar jarfile [args...] In other words, the way you've got it at the moment will treat -Dtest="true" as one of the arguments to pass to main instead of as a JVM argument. (You should probably also drop the quotes, but it may well work anyway - it probably depends on your shell.) That should be: java -Dtest="true" -jar myApplication.jar Then the following will return the value: System.getProperty("test"); The value could be null, though, so guard against an exception using a Boolean: boolean b = Boolean.parseBoolean( System.getProperty( "test" ) ); Note that the getBoolean method delegates the system property value, simplifying the code to: if( Boolean.getBoolean( "test" ) ) You're giving parameters to your program instead to Java. Use java -Dtest="true" -jar myApplication.jar instead. Consider using "true".equalsIgnoreCase(System.getProperty("test")) to avoid the NPE. But do not use " Yoda conditions" always without thinking, sometimes throwing the ...