如何在另一个Jar中多次调用具有另一个Jar中的参数的Java类

Question

I have a project in RAD. Package is inputFileEdit, and the java class I need is InputFileTest.java.

package inputFileEdit;

public class InputFileTest {

    public static void main(String[] args) {
        String var1 = args[0];
        String var2 = args[1].toLowerCase();

        // do stuff with args
    }
}

I want to create a new package / java program that can call or instantiate the class InputFileTest above, with arguments, multiple times in parallel. I'm basically going to be bringing back a String list, looping through that list to create parallel threads, each row on the list calling InputFileTest.

Question 1) What's the best way to call InputFileTest? I'm using RAD and I created a new Project, a package called CallerPackage, and a Caller.java inside that package? I also including a "Jar" of the whole InputFileEdit project under /lib via Java Build Path -> Libraries -> Add External Jars. I don't know how to call the class with parameters (I tried something like InputFileEdit ifeObj = new InputFileEdit("parm 1", "parm 2"); or InputFileEdit ifeObj = new InputFileEdit("parm 1 parm 2"); ) but neither worked so then I tried to just call the jar like Process p = Runtime.getRuntime().exec("java -jar /lib/InputFileEdit.jar parm1 parm2"); or since I want the actual Class InputFileTest, Process p = Runtime.getRuntime().exec(new String[]{"java","-cp","/lib/InputFileEdit.jar", "InputFileTest", "parm1","parm1"}); :

package CallerPackage;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
//import inputFileEdit.*;

public class Caller {

     static int i = 0;

        public static void main(String args[]) throws IOException, InterruptedException {
            try {
                System.out.println("Calling jar");
                Process p = Runtime.getRuntime().exec("java -jar /lib/InputFileEdit.jar parm1 parm2");

BufferedInputStream errStrm = new BufferedInputStream(p.getErrorStream());   

                // get the error stream of the process and print it
                for (int i = 0; i < errStrm.available(); i++) {
                    System.out.println("" + errStrm.read());
                }

                System.out.println("Called jar");

                p.destroy();

            } 
            catch (Exception ex) {
                ex.printStackTrace();
            }

       }
}

but this doesn't seem to work either or print out anything helpful. Any ideas of the best way to go about this? I'm only trying to get 1 call to work for now before I loop through my list and call them in parallel. Eventually it'll be calling the jar/class looping through a string arraylist.

Answer 1

you should be able to call the main method in InputFileTest the same way you would call any other static method: InputFileTest.main(args);

However, generally directly calling main is frowned upon. If you are able, I would advise you to take the code in InputFileTest's main, and put it into another, more descriptively named method, something like processFiles .