从文本文件读取为arraylist / hashmap

Question

Okay so here's an explanation of what I have to write:

• getBreadInfo - reads bread.txt into an array list (containing bread name, $, and price) and then assigns to an array breadInfo[], then return this array for SandwichApp to display bread menu.
• getBread - is similar to getBreadInfo, except it only contains the bread name, and return another array bread[] for SandwichApp to figure out which bread the user selected because user type in a number associate with the bread (index+1), rather than bread name.
• getMapBreadPrice - is similar to the above two, except it returns a hash map containing pair values for bread name (key) and price (value) for SandwichApp to figure out what is the price for the bread user selected.

This is what I have written. Just wondering if this is correct or not?

public class SandwichDB {  
private ArrayList<String> breadsList = null;

public String[] getBreadInfo()
{ 
    breadsList = new ArrayList<>();

        try (BufferedReader in =
                new BufferedReader(
                new FileReader("bread.txt")))
        {
            String line = in.readLine();
            while (line != null)
            {
                String[] elems = line.split("~");
                breadsList.add(elems[0]+ " $" + elems[1]);  
            }

        }
        catch(IOException e)
        {
            System.out.println(e);
            return null;
        }
    String[] breadInfo = breadsList.toArray(new String[]{});
    return breadInfo;
}
public String[] getBread()
{
    breadsList = new ArrayList<>();

        try (BufferedReader in =
                new BufferedReader(
                new FileReader("bread.txt")))
        {
            String line = in.readLine();
            while (line != null)
            {
                String[] elems = line.split("~");
                breadsList.add(elems[0]);  
            }

        }
        catch(IOException e)
        {
            System.out.println(e);
            return null;
        }
        String[] bread = breadsList.toArray(new String[]{});
        return bread;
}
public HashMap<String, String> getMapBreadPrice()
        {
            HashMap<String, String> mapBreadPrice = new HashMap<>();
            String line, elems[];
            try
            {
                FileReader fr = new FileReader("bread.txt");
                BufferedReader br = new BufferedReader(fr);

                while ((line=br.readLine()) != null)
                {
                    elems = line.split("~");
                    mapBreadPrice.put(elems[0], elems[1]);
                }
            }
            catch(IOException e)
            {
                System.out.println(e);
                return null;
            }
            return mapBreadPrice;
        }
        }

Answer 1

The first readLine stands before the while and hence is not repeated. Hence the while does not end.

for (;;) {
    String line = in.readLine();
    if (line == null) {
        break;
    }

Answer 2

It seems like you're reading the same file 3 times in order to build 3 structures. You should build your data structures with one read of the file.