如何使用CompareTo()和TreeSet()

我有两个文件,行如下:ProductName(String);产品代码(字符串);SellData(Int)。

class Gyumi implements Comparable<Gyumi> {
   String termek = "";
   String termekkod = "";
   int[] evek = new int[3];

  @Override
  public String toString() {
      return termek + ", " + termekkod + ", " + Arrays.toString(evek);
  }

  @Override
  public int compareTo(Gyumi t) {
      if(termekkod >((Gyumi)t.termekkod){
          return 1;
      }
      if(termekkod <((Gyumi)t.termekkod){
        return -1;
      }
        return 0;
    }
 }
}

public class Gyumolcs {

static ArrayList<Gyumi> lista = new ArrayList<Gyumi>();
static ArrayList<Gyumi> lista2 = new ArrayList<Gyumi>();
static TreeSet<Gyumi> halmaz = new TreeSet<Gyumi>();

public static void Feltolt() {
    File r = new File("termekkod_uzlet2.csv");
    File f = new File("termekkod_uzlet1.csv");
    try {
        Scanner scan = new Scanner(f, "iso-8859-2");
        while (scan.hasNextLine()) {
            String sor = scan.nextLine();
            String[] tomb = sor.split(";");
            Gyumi gy = new Gyumi();
            gy.termek = tomb[0];
            gy.termekkod = tomb[1];
            gy.evek[0] = Integer.parseInt(tomb[2]);
            gy.evek[1] = Integer.parseInt(tomb[3]);
            gy.evek[2] = Integer.parseInt(tomb[4]);
            lista.add(gy);
            halmaz.add(gy);
        }
    } catch (Exception e) {
        System.out.println("Hiba " + e.getMessage());
    }
    try {
        Scanner scan2 = new Scanner(r, "iso-8859-2");
        while (scan2.hasNextLine()) {
            String sor = scan2.nextLine();
            String[] tomb = sor.split(";");
            Gyumi gy = new Gyumi();
            gy.termek = tomb[0];
            gy.termekkod = tomb[1];
            gy.evek[0] = Integer.parseInt(tomb[2]);
            gy.evek[1] = Integer.parseInt(tomb[3]);
            gy.evek[2] = Integer.parseInt(tomb[4]);
            lista2.add(gy);
            halmaz.add(gy);
        }
    } catch (Exception e) {
        System.out.println("valami" + e.getMessage());
    }
}

public static void main(String[] args) {
    Feltolt();
    System.out.println(halmaz);
  }
}