Thread: Difficulty in creating/writing to a file (also, with reading file with data)

Hi guys.

 
/*
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package daos;
 
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import model.City;
import model.YearData;
 
import repositories.Repository;
 
/**
 *
 * @author mga
 */
public class DAOTextImpl implements DAOInterface {
      private ArrayList<YearData>yeardata;
 
    static final char DELIMITER=',';   
 
 
 
 
    @Override
    public Repository load(String filename) {
 
        Repository repository = new Repository();
 
        try (BufferedReader br = new BufferedReader(new FileReader(filename))) { 
            String[] temp;
            String line = br.readLine();
            while(line!=null){
                temp=line.split(Character.toString(DELIMITER));        
                int id = Integer.parseInt(temp[0]);
                String cityName = stripQuotes(temp[1]);
                String country=stripQuotes(temp[2]);
                City city=new City (id, cityName, country);
 
 
 
 
                  /*  line=br.readLine();
                    temp=line.split(Character.toString(DELIMITER));
                    String year=stripQuotes(temp[4]);
                    float precipitation=Float.parseFloat(temp[5]);
                    int maxTemp=Integer.parseInt(temp[6]);
                    int minTemp=Integer.parseInt(temp[7]);
                    int windSpeed=Integer.parseInt(temp[8]);
                    String windDirection=stripQuotes(temp[9]);
                 YearData yeardata=new YearData(year, precipitation, maxTemp, minTemp,windSpeed, windDirection); */
 
               repository.getItem(id);
 
             //   repository.add(city);
 
                line = br.readLine();                
            }
 
 
 
 
 
 
 
            br.close();
        } catch (IOException ex) {
            Logger.getLogger(DAOTextImpl.class.getName()).log(Level.SEVERE, null, ex);
        }
        return repository;
 
    }
 @Override
    public void store(String filename, Repository repository) {
            try (PrintWriter output = new PrintWriter(filename)) {
 
 
           output.print(repository.toString());
 
            output.close();
 
        } catch (FileNotFoundException ex) {
            Logger.getLogger(DAOTextImpl.class.getName()).log(Level.SEVERE, null, ex);
                }
 
        }        
 
 
 
    private String stripQuotes(String str) {
        return str.substring(1, str.length()-1);
    }
}

I am having problems with the above code. Whenever I run the code, all I get is:

[] I suspect that this is due to the fact that the array is empty....i.e. is not being read properly and so returns its default value, i.e. NULL.


Whenever I try and open a file, I get NumberFormatException. This, I suspect is due to the fact that it contains illegal characters, such as a date, floats etc.

I am also unsure as to how I would utilise an arraylist of objects, I have two (model) classes. One class contains an ArrayList, the second class contains the member variables which are to populate the ArrayList. However, I am utterly baffled as to what I do to implement the ArrayList with the code above. I cannot convert it to String, so this means that using something like:

ArrayList<String> result = new ArrayList<>();

try (FileReader f = new FileReader(filename)) {
StringBuffer sb = new StringBuffer();
while (f.ready()) {
char c = (char) f.read();
if (c == '\n') {
result.add(sb.toString());
sb = new StringBuffer();
} else {
sb.append(c);
}
}
if (sb.length() > 0) {
result.add(sb.toString());
}
}
return result;

For example, won't work due to the mismatch due to string/object.



Cab anyone please advise me? I'm totally stuck