Run R script using JAVA program

Question

I am new to R programming. I have created a simple R script and trying to run it using JAVA class, but I am unable to do it.

I have tried by using Rserve as well as rJava. Using Rserve, code execution stopped after creating instance of "RConnection" whereas using rJava giving exception "java.lang.UnsatisfiedLinkError: jri.dll: Can't find dependent libraries".

The JAVA class code is as below:

For rJava:

    import org.rosuda.JRI.Rengine;
public class Temp {

public static void main(String a[]) {
    // Create an R vector in the form of a string.
    String javaVector = "c(1,2,3,4,5)";

    // Start Rengine.
    Rengine engine = new Rengine(new String[] { "--no-save" }, false, null);

    // The vector that was created in JAVA context is stored in 'rVector' which is a variable in R context.
    engine.eval("rVector=" + javaVector);

    //Calculate MEAN of vector using R syntax.
    engine.eval("meanVal=mean(rVector)");

    //Retrieve MEAN value
    double mean = engine.eval("meanVal").asDouble();

    //Print output values
    System.out.println("Mean of given vector is=" + mean);

}
}

For Rserve:

import org.rosuda.REngine.REXPMismatchException;
import org.rosuda.REngine.Rserve.RConnection;
import org.rosuda.REngine.Rserve.RserveException;
public class Temp {

public static void main(String a[]) {
    RConnection connection = null;
    System.out.println("line 10");
    try {
        // Create a connection to Rserve instance running on default port 6311

        System.out.println("line 15");
        connection = new RConnection();
        System.out.println("line 17");
        //Note four slashes (\\\\) in the path
        connection.eval("source('D:\\\\RExamples\\\\helloworld.R')");
        System.out.println("line 19");
        int num1=10;
        int num2=20;
        int sum=connection.eval("myAdd("+num1+","+num2+")").asInteger();
        System.out.println("The sum is=" + sum);
    } catch (RserveException e) {
        e.printStackTrace();
    } catch (REXPMismatchException e) {
        e.printStackTrace();
    }
}
}

Please let me know if my question is not clear to you or if you want to know anything else. Thanks in advance.

Answer 1

You just want to call an external application: wouldn't the following work?

Runtime.getRuntime().exec("Rscript myScript.R"); 

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