Convert ArrayList fetched from HashMap to an Array

Question

How can i do this ? When i stored my fields in HashMap , i did it like simple Objects

HashMap map = new HashMap();

    map.put ("Autorul",numelePrenumeleAutorului);
    map.put ("Denumirea cartii",denumireaCartii);
    map.put ("Culoarea cartii",culoareaCartii);
    map.put ("Genul cartii",gen);
    map.put ("Limba",limba);
    map.put ("Numarul de copii",numarulDeCopii);
    map.put ("Numarul de pagini",numarulDePagini);
    map.put ("Pretul cartii",pretulCartii);

     ArrayList arl=new ArrayList();

     for (int i = 0;i<numarulDeCopii;i++) {

     arl.add(coeficientUzura[i]);
}
     map.put ("Coeficientii de Uzura",arl);

I access values from HashMap (look for the last lines)

Carte (String caleSpreFisier) {

HashMap map = new HashMap();

File file = new File(caleSpreFisier); 

try  {

FileInputStream f = new FileInputStream(file);  
ObjectInputStream s = new ObjectInputStream(f);  
map = (HashMap)s.readObject();         
s.close();

 } catch(Exception e){

           System.out.println("An exception has occured : "+e);     
    }

for (Object key :map.keySet()) {

    if (key.equals("Autorul")) {

        numelePrenumeleAutorului = (String)map.get(key);

    }

      if (key.equals("Denumirea cartii")) {

      denumireaCartii = (String) map.get(key);
    }

    if (key.equals("Culoarea cartii")) {

        culoareaCartii = (String)map.get(key);
    }


    if (key.equals("Genul cartii")) {

        gen = (String) map.get(key);

    }

    if (key.equals("Limba")) {

        limba = (String) map.get(key);

    }

    if (key.equals("Numarul de copii")) {

        numarulDeCopii = (Integer) map.get(key);

    }

    if (key.equals("Numarul de pagini")) {

        numarulDePagini = (Integer) map.get(key);

    }

    if (key.equals("Pretul cartii")) {

         pretulCartii = (Double) map.get(key);
    }

    if (key.equals("Coeficientii de Uzura")) {

        ArrayList temp = new ArrayList();


        Object me = map.get(key);

        System.out.println(me);

        //temp = (ArrayList) map.get(key);
    }   
}

score 0 · Accepted Answer · answered Sep 30 '11 at 08:15

0

Object[] array = ((ArrayList) map.get(key)).toArray();

answered Sep 30 '11 at 08:15

dacwe

43,066
12
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140

score 0 · Answer 2 · edited May 23 '17 at 10:26

0

First of: you're in object denial. Your HashMap should really be a proper class that you wrote with the real properties to hold your different fields.

That way you also don't have to do that ugly "name of the property"-to-local-variable mapping.

Next: if what you put into the map is an ArrayList, then you can just cast what you get out to that type again:

ArrayList temp = (ArrayList) map.get(key);

edited May 23 '17 at 10:26

Community

1
1

answered Sep 30 '11 at 08:17

Joachim Sauer

302,674
57
556
614

thx, but what about name of properties , this is normal cause a typed names in my native language – Sep 30 '11 at 08:20

Convert ArrayList fetched from HashMap to an Array

2 Answers2