'Java read file by command line, <(less than) symbol

I am trying to read the filename by the command line,

This is command that our professor wants us to type:

java MultiBinaryClient xxxxxx.edu 6001 < files.txt

I was trying to use args[3] to get the file name, but args only contains "xxxxxx.edu" and "6001". why not "<" and "files.txt" in the args[]? Can anyone help me out?

BTW, I am using MAC terminal to test my code, I believe my professor uses win CMD, will it make differences?

Thank you!

javacmdterminalcommand-line-arguments


Solution 1:[1]

Let's see what each fragment means. This is how we execute a Java class containing a main method:

java MultiBinaryClient

The only command-line arguments that are being passed to your program are these ones:

xxxxxx.edu 6001

And this snippet is not part of the expected arguments to the Java program:

< files.txt

It's just Unix shell syntax to specify that the contents of files.txt must be read into your program via the standard input.

Solution 2:[2]

I know it's an old question, but I've had this problem recently. Here's what I've done to handle it:

Well, as the others said, the "<" redirects the file contents to stdin. If you want to use the file contents as program arguments, you can use xargs:

xargs -a FILE java JAVA_ARGS

or, more specifically:

xargs -a FILE java -cp CLASSPATH CLASS_WITH_MAIN_METHOD

Solution 3:[3]

< is a redirection. The file will be streaming over stdin.

Solution 4:[4]

You should escape the '<'

java MultiBinaryClient xxxxxx.edu 6001 \< files.txt

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Gabriel dos Santos
Solution 3 Alex Fitzpatrick
Solution 4 tianwei

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