Question

I need to read two files by using multiple threads and print the content of the files in the console.The user will enter the file paths and use the threads to read the contents of the files. I have a hard time understanding files. Can anyone just suggest me what should be done in the run method?

import java.io.*;

public class Ch3Ex4 implements Runnable
 {
  public void ReadFile(String str,Thread thread)
   {
    try
     {
      File inputFile = new File(str);
      FileInputStream in = new FileInputStream(inputFile);
     }
    catch(Exception e)
    {
        e.printStackTrace();
    }
  } 
    public void run()
      {

      } 

 public static void main (String[] args)
  {
    try
    {
    Ch3Ex4 obj = new Ch3Ex4();
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    System.out.println("Enter the two file paths:");
    String s1 = br.readLine();
    String s2 = br.readLine();
    Thread thread1 = new Thread(obj);
    Thread thread2 = new Thread(obj);
    obj.ReadFile(s1, thread1);
    obj.ReadFile(s2, thread2);
    thread1.start();
    thread2.start();
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
  }
 }

Answer 1

The run method is meant to contain the code which is executed by that thread. So, as you want to read two files from two different threads, you’ll need to use run for doing whatever you’re doing in ReadFile method.

Note that you’ll need to create an instance of Ch3Ex4 class and invoke the start method in order to start to start a new thread.

EDIT: In that case, you can use a BufferedReader inside the run method like this: (From mkyong‘s website)

    BufferedReader br = null;

    try {

        String sCurrentLine;

        br = new BufferedReader(new FileReader("C:\\testing.txt"));

        while ((sCurrentLine = br.readLine()) != null) {
            System.out.println(sCurrentLine);
        }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            if (br != null)br.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }