Storing objects in hashmap

[Rajendra Prakash]

The following code used to store and retrieve values in hashmap
HashMap<Integer,String>hmap = new HashMap<Integer,String>();
hmap.put(5,"prak");
hmap.put(1," sachin");

hmap.put(4,"raja");
hmap.put(4,"raja");
Iterator itr= hmap.entrySet().iterator();
while(itr.hasNext())
{
System.out.println(itr.next());
}
Give me idea for this situation. I need to store objects(long empid,String name, int salary, String Designation)in
hashmap , use empid as key for all the objects.

[Rahul Nair]

Hi,

You can also store the Model Class/Form Bean object to the HashMap, and as use that object's property as a key in HashMap.

Please let me know, if you have any issue.

[Hunter McMillen]

So just create a HashMap and make the key the empid field and the value the entire object.

Hunter

[Fred Muhlenberg]

When you store User defined objects in a hashmap (or any collection for that matter), you need to implement the equals() and hashMap() methods. the default implementations of these methods (from java.lang.Object) is generally not sufficient

-Fred.

[Ernest Friedman-Hill]

Fred Muhlenberg wrote:When you store User defined objects in a hashmap (or any collection for that matter), you need to implement the equals() and hashMap() methods. the default implementations of these methods (from java.lang.Object) is generally not sufficient

This is absolutely true of any objects used as keys in a HashMap; the "value" half of the key/value pair doesn't actually benefit from having these methods. They're important, though, if you want to store the values in a List or Set and be free to use all of the methods of those interfaces.