Store an array in HashMap
i'm new to Java. How can i store an array of integers values in a HashMap, after that i write this HashMap in a txt file but this isn't important at the moment. I can store single fields but not an array. Any ideas ?
public void salveazaObiectulCreat(String caleSpreFisier) {
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);
m开发者_JAVA百科ap.put ("Numarul de pagini",numarulDePagini);
map.put ("Pretul cartii",pretulCartii);
try {
File file = new File(caleSpreFisier);
FileOutputStream f = new FileOutputStream(file);
ObjectOutputStream s = new ObjectOutputStream(f);
s.writeObject(map);
s.close();
} catch(Exception e){
System.out.println("An exception has occured");
}
}
HashMap<String, List<Integer>> map = new HashMap<String, List<Integer>>();
HashMap<String, int[]> map = new HashMap<String, int[]>();
pick one, for example
HashMap<String, List<Integer>> map = new HashMap<String, List<Integer>>();
map.put("Something", new ArrayList<Integer>());
for (int i=0;i<numarulDeCopii; i++) {
map.get("Something").add(coeficientUzura[i]);
}
or just
HashMap<String, int[]> map = new HashMap<String, int[]>();
map.put("Something", coeficientUzura);
Not sure of the exact question but is this what you are looking for?
public class TestRun
{
public static void main(String [] args)
{
Map<String, Integer[]> prices = new HashMap<String, Integer[]>();
prices.put("milk", new Integer[] {1, 3, 2});
prices.put("eggs", new Integer[] {1, 1, 2});
}
}
Yes, the Map interface will allow you to store Arrays as values. Here's a very simple example:
int[] val = {1, 2, 3};
Map<String, int[]> map = new HashMap<String, int[]>();
map.put("KEY1", val);
Also, depending on your use case you may want to look at the Multimap support offered by guava.
If you want to store multiple values for a key (if I understand you correctly), you could try a MultiHashMap (available in various libraries, not only commons-collections).
Your life will be much easier if you can save a List as the value instead of an array in that Map.
You can store objects in a HashMap.
HashMap<String, Object> map = new HashMap<String, Object>();
You'll just need to cast it back out correctly.
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