如何通过终端将文本文件输入到 Java 程序中（就像在 C++ 中是如何完成的那样）？

Question

If i do

$ java ProgramName string1 string2 string3

from the linux terminal, ProgramName gets string1 string2 string3 via main(String arg[]) using arg[i] , and all is well.

Here's what I want to do: Instead of typing string1 string2 string3 at the terminal, i want to type

$ java ProgramName < input.txt

where "input.txt" contains string1, string2, and string3

Edit: "input.txt" has one word on a separate line with an 'enter' at the end of the line

string1

string2

stringn

This can be done it C++ ; can it be done similarly in Java?

Answer 1

You can do:

export parameters=`cat file.txt`
java programname $parameters

note the inverse ` (not ')

or even:

java programname `cat file.txt`

Answer 2

Since you are redirecting a file to the standard input of your program, you can try the following:

Scanner in = new Scanner(System.in);
String line = new String();
while(in.hasNext())//while there are lines on the file
{
    line = in.nextLine();//read the line
    //do stuff here
}

Answer 3

Please use this command:

java MyProg "$(cat file.txt | tr '\n' ' ')"

If its not working please check that arguments are properly defined in source file.