Java, assigning variables from files

Question

I was wondering how I would create a java program which reads from a file and assigns variables.

import java.io.*;

public class Reader {
    public static void main(String[] args) {
        String str;
        String time=null;
        try  {
            BufferedReader reader = new BufferedReader(new FileReader("pathfilehere"));
            while((a = reader.readLine()) != null) {
                reader.readLine();
            }
        } catch(FileNotFoundException e){System.out.println("Error: "+e.getMessage());
        } catch(IOException e){System.out.println("Error: "+e.getMessage());
        }
        System.out.println(time);
    }
}

If I have a txt file with a variable "str" and its value is "randomstring", my question is how can I tell my java program to assign this variable from the text file and store it into the java program to use later on?

Read the text file into a Map<String, String>. Hopefully you're using a standard serialization, like JSON, so you don't have to roll your own parser. — Matt Ball
– Matt Ball, Commented Sep 11, 2013 at 2:27
If you have key values pairs, then you can use the Properties class which can read the key value paired data in a file and interpret them as properties — Prasad Kharkar
– Prasad Kharkar, Commented Sep 11, 2013 at 2:28
+1 for "use the Properties class". Unless I'm reading the question wrong, that's exactly what you're looking for. Here's the JavaDoc for Properties. Here's a related question and here's a tutorial. — jahroy
– jahroy, Commented Sep 11, 2013 at 2:39
java has serialization : store object to file and recreate same obj when you need , is that what you need . tutorialspoint.com/java/java_serialization.htm — Srinath Ganesh
– Srinath Ganesh, Commented Sep 11, 2013 at 3:25

upog · Accepted Answer · 2013-09-11 02:43:27Z

1

import java.io.*;

public class Reader {
    public static void main(String[] args) {

        BufferedReader reader = null;
        StringBuilder randomstring =  new StringBuilder();
        try  {
             reader = new BufferedReader(new FileReader("file.txt"));


            String line = reader.readLine();
            while(line !=  null) {
                randomstring.append(line + '\n');

                 line = reader.readLine();
            }
        } catch(FileNotFoundException e){System.out.println("Error: "+e.getMessage());
        } catch(IOException e){System.out.println("Error: "+e.getMessage());
        }
        finally{
            try{
                reader.close();
            }catch(Exception E){}
        }
        System.out.println(randomstring.toString());
    }
}

answered Sep 11, 2013 at 2:43

upog

5,6268 gold badges57 silver badges87 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

lreeder Over a year ago

How does this code sample answer the question? Looks like it's just printing out the lines in the file, not making them available for later use by the code.

Arc Over a year ago

It looks great, but lets just say for example, I'm making a bank account program. I need to be able to read the accounts information from the file and then use it later on in the program? How would I go upon doing that? (I quickly made the program used in the example just to show in a way what I wanted to do, although it does just print out the value in the txt file, I would like to know how I can use the value in the txt file later on)

Collectives™ on Stack Overflow

Java, assigning variables from files

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related