CODEWITHSUNDEEP
java
upendra
upendra

Reputation: 49

Retrieve the value<List> from the Map and store the each value in the String variable

I am not able to convert the value which is the List<String>, of the Map into the String.

Source code is as follows:

Map<String ,List<String>> profileFields)

String argValue[] = null;
    int loopCounter = 0;


    Object[] obj = profileFields.values().toArray();
    for(int i = 0 ; i < obj.length ; i++){
        System.out.println("Values####"+obj[i]);
        argValue[loopCounter] = (String) obj[i];
     }

This code is not working.

Please let me know, how I am able to convert these values to String.

Upvotes: 1

Views: 978

Answers (4)

stacker
stacker

Reputation: 69002

You forgot to initialze argValue:

String argValue[] = new String[ profileFields.values().size() ];

and

loopCounterisn't incremented either resue i or loopCounter++

This would work:

ArrayList<String> allLists = new ArrayList<String>();
for ( List<String> list : profileFields.values() ) {
    allLists.addAll( list );
}
String[] argValue = new String[ allLists.size() ];

for ( int i = 0 ; i < argValue.length ; i++ ) {
    argValue[i] = allLists.get( i );
    System.out.println( "Values####" + argValue[i] );
}

EDIT:

You also replace the last loop (without printing) by

String[] stringArray = Arrays.copyOf(objectArray, objectArray.length, String[].class);

Upvotes: 0

Shivan Dragon
Shivan Dragon

Reputation: 15229

Map<String, List<String>> profileFields = new HashMap<String, List<String>>();
        profileFields.put("s1", new ArrayList<String>() {
            {
                add("l11");
                add("l12");
            }
        });
        profileFields.put("s2", new ArrayList<String>() {
            {
                add("l21");
                add("l22");
            }
        });

        List<String> argValue[] = null;
        int loopCounter = 0;

        //this will get you an array of elements, each element representing a Map value
        //your map Values are if type List<String>, so you'll get an array of Lists
        Object[] obj = profileFields.values().toArray();
        for(int i = 0 ; i < obj.length ; i++){
            System.out.println("Values####"+obj[i]);
            argValue[loopCounter] = (List<String>) obj[i];
         }

Upvotes: 0

John B
John B

Reputation: 32969

Your array is an array of List<String>.

Object[] obj = profileFields.values().toArray();

is actually

List<String>[] obj = profileFields.values().toArray();

because values is returning a collection of List objects.

Also Consider using Guava's ListMultimap which implements a Map of Lists.

Upvotes: 1

Jonathan
Jonathan

Reputation: 2776

You are missing the instantiation of the argValue-array.

Map<String ,List<String>> profileFields)
String argValue[] = null;
int loopCounter = 0;

Object[] obj = profileFields.values().toArray();

argValue = new String[obj.length];

for(int i = 0 ; i < obj.length ; i++){
    System.out.println("Values####"+obj[i]);
    argValue[loopCounter] = (String) obj[i];
 }

Upvotes: 1

Related Questions