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in Technique[技术] by (71.8m points)

how to read data from file into array in Java?

I need some help reading data from a text file into my ArrayList. The first part with the creating and putting the ArrayList into the text file works perfectly. I just need some help at the end in the "marked" area.

Note that some identifiers are in my native language.

public class ContAngajat {   
   String username;
   String password;
}

public class CreazaCont {

// creating the arraylist and putting it into a file 

public static void  ang(String args[])   { 

    ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50);

 Scanner diskScanner = new Scanner(in);

 Scanner forn = new Scanner(in);


 int n;

     out.print("Introduceti numarul de conturi noi care doriti sa le introduceti: ");
     n=forn.nextInt();
  out.println();

     try{

    FileWriter fw = new FileWriter("ConturiAngajati.txt", true);


    for(int i=0; i<n; i++){
  ContAngajat cont = new ContAngajat();

  out.print("Username: ");
  cont.username=diskScanner.nextLine();


  out.print("Password: ");
  cont.password=diskScanner.nextLine();

  angajati.add(cont);

  fw.write(cont.username + " ");
  fw.write(cont.password +"|");


  }
  fw.close();
     }
     catch(IOException ex){

      System.out.println("Could not write to file");

      System.exit(0);
     }




 for (int i=0; i<n; i++) {
  out.println("username: " + angajati.get(i).username + "  password: " +angajati.get(i).password );

 }


  }


// HERE I'M TRING TO GET THE ARRAYLIST OUT OF THE FILE

public static void  RdAng(String args[])   { 

 ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50);
 ContAngajat cont = new ContAngajat();
 int count,i2,i;

 try{


   FileReader fr = new FileReader("ConturiAngajati.txt");
   BufferedReader br = new BufferedReader(fr);

   String line = "";


   while((line=br.readLine())!=null) {

   String[] theline=line.split("|"); 
   count=theline.length;

   for(i=0;i<theline.length;i++) {

   String[] theword = theline[i].split(" "); 
  }     

   }   

   for(i2=0;i2<count;i2++)  {

   ContAngajat contrd = new ContAngajat();

// "ERROR" OVER HERE 

 for (int ird=0; ird <theword.length; ird++) {  

 cont.username=theword[0];
     cont.password=theword[1];

// they keep telling me "theword cannot be resolved" whenever i try to run this

}
       angajati.add(contrd); 
 }

 } 


 catch(IOException ex){

      System.out.println("Could not read to file");

      System.exit(0);
     }
}


}

The compilation error is theword cannot be resolved.

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1 Reply

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by (71.8m points)

they keep telling me "theword cannot be resolved" whenever I try to run this

This means that theword is not declared in the scope. You cannot access it to invoke any methods. They have it right. You need to declare theword in a broader scope, or to move the code which depends on theword into the scope where it is been declared. Maybe you've declared it inside an if or while block or so and you're trying to use it outside the block where it is been declared. That ain't going to work.

A more detailed answer may be given whenever you clean up the code so that it's better readable.


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