[Q#18070629][A#18070669] How to read from user's input in Java and write it to a file

https://stackoverflow.com/q/18070629

I want to create a simple stand-alone application that will take some input from user (some numbers and mathematical functions f(x,y…)) and write them to a file. Then with the help of this file I will run a command. Basic ingredients that I need: – JTextArea for users input. – ButtonHandler/ActionListener and writing of the input to a (txt) file – ButtonHandler/ActionLister to execute a command What is the best way to do it? A current running code that I have (basically a toy) - which does not write anything, just executes - is: In the above example how can I write 'value' to a file? Then, how can I add more input (more textfields)? Can I do it in the same class or I need more? My confusion comes (mainly but not only) from the fact that inside the ButtonHandler class I can NOT define any other objects (ie, open and write files etc).

Answer

https://stackoverflow.com/a/18070669

This is the way I would write to a file. I will let you convert this code into your GUI for practice. See more on BufferedWriter and FileWriter

APIzation

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Scanner;

public class Files {

    public static void main(String args[]){

        System.out.print("Enter Text: ");
        Scanner scan = new Scanner(System.in);
        String text = scan.nextLine();
        FileWriter fWriter = null;
        BufferedWriter writer = null;
        try {
          fWriter = new FileWriter("text.txt");
          writer = new BufferedWriter(fWriter);
          writer.write(text);
          writer.newLine();
          writer.close();
          System.err.println("Your input of " + text.length() + " characters was saved.");
        } catch (Exception e) {
            System.out.println("Error!");
        }
    }

}

package com.stackoverflow.api;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Scanner;

public class Human18070669 {

  public static void writeToFile(String str1) {
    System.out.print("Enter Text: ");
    Scanner scan = new Scanner(System.in);
    String text = scan.nextLine();
    FileWriter fWriter = null;
    BufferedWriter writer = null;
    try {
      fWriter = new FileWriter(str1);
      writer = new BufferedWriter(fWriter);
      writer.write(text);
      writer.newLine();
      writer.close();
      System.err.println(
        "Your input of " + text.length() + " characters was saved."
      );
    } catch (Exception e) {
      System.out.println("Error!");
    }
  }
}

package com.stackoverflow.api;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Scanner;

/**
 * How to read from user's input in Java and write it to a file
 *
 * @author APIzator
 * @see <a href="https://stackoverflow.com/a/18070669">https://stackoverflow.com/a/18070669</a>
 */
public class APIzator18070669 {

  public static void read(String str1) {
    System.out.print("Enter Text: ");
    Scanner scan = new Scanner(System.in);
    String text = scan.nextLine();
    FileWriter fWriter = null;
    BufferedWriter writer = null;
    try {
      fWriter = new FileWriter(str1);
      writer = new BufferedWriter(fWriter);
      writer.write(text);
      writer.newLine();
      writer.close();
      System.err.println(
        "Your input of " + text.length() + " characters was saved."
      );
    } catch (Exception e) {
      System.out.println("Error!");
    }
  }
}