Java-按字母和数字顺序对带有对象的数组列表进行排序

Question

Im reading Classroom names ("B106") from a text file and saving them on a Array list. I need to sort that Array by letter and then by number. I read something about using Collections / Comparator but I wasnt able to implement them sucessfully, how can I do this?

Ex: Input: "B106", "D111", "A201", "B102"

Output: "A201", "B102", "B106", "D111"

Class Core_Salas where I manage my files

public class Core_Sala {

//---------------------------------------------------------------------------
public static ArrayList<Sala> Sala = new ArrayList<Sala>();
private static File SF = new File("Salas.txt");
public static void LerSalas()
{

    try
    {
        if(SF.exists()==true)
        {
            String[]parts;
            Sala.clear();//Array list limpar
            Scanner inputFile = new Scanner(SF);
            while (inputFile.hasNextLine()) {
                String line = inputFile.nextLine();
                Sala s1 = new Sala(line);
                Sala.add(s1);
            }
            inputFile.close();
        }
    } catch (FileNotFoundException e) 
    {
        e.printStackTrace();
    }
    if(SF.exists()==false)
    {
        PrintWriter out = null;
        try
        {
            out = new PrintWriter(SF);

        }catch (FileNotFoundException e) {
            JOptionPane.showMessageDialog(null, "O ficheiro de utilizadores estava danificado ou era inexistente, foi criado um novo com o utilizador admin!");
        }
        out.close();
    }
}
}

Class Sala with getter Setter and Constructor

public class Sala {
private String Salas;

public Sala(String salas)
{
    this.Salas=salas;
}
public String getSalas() {
    return Salas;
}
public void setSalas(String salas) {
    Salas = salas;
}

@Override
public String toString()
{
    return Salas;
}
}

Answer 1

Collections.sort() method can help you.

Example:

public class TestSort {
  public static void main(String args[]) {
    String init[] = {"B106", "D111", "A201", "B102"};
    List list = new ArrayList(Arrays.asList(init));
    System.out.println("Input: " + list);
    Collections.sort(list);
    System.out.println("Output: " + list);
  }
}

Answer 2

You can try this

 public static void main(String[] args) {
    LerSalas();
    Collections.sort(salaData, new Comparator<Sala>() {
        @Override
        public int compare(Sala o1, Sala o2) {
            return o1.getSalas().compareTo(o2.getSalas());
        }
    });
    salaData.stream().forEach(System.out::println);
}

let me know if it works for you

Answer 3

For my opinion,if your Sala Class has only one attribute that is String type,Then you no need to make Sala Class.You can add String directly to arrayList.and Use Collections.sort(),then it will sort alphabatically and numerically.For eg:

public class Test {

    public static void main(String args[]){
        List al = new ArrayList();
        al.add("B106");al.add("A201");al.add("D111");al.add("BC102");
        Collections.sort(al);
        System.out.println(al);
    }
}

but if you have to use Sala class,then you can implements Comparator or Comparable Interface.