I have a hashMap of Integer,String (K,V) and want to write only the string values to a file (not the key Integer) and I want to write only some 1st n entries (no specific order) to the file and not the entire map. I have tried looking around a lot but could not find a way to write 1st n entries to file.(There are examples where I can convert the value to array of Strings and then do it] but then it does not provide the correct format in which I want to write the file)
This sounds like homework.
public static void main(String[] args) throws IOException {
// first, let's build your hashmap and populate it
HashMap<Integer, String> map = new HashMap<Integer, String>();
map.put(1, "Value1");
map.put(2, "Value2");
map.put(3, "Value3");
map.put(4, "Value4");
map.put(5, "Value5");
// then, define how many records we want to print to the file
int recordsToPrint = 3;
FileWriter fstream;
BufferedWriter out;
// create your filewriter and bufferedreader
fstream = new FileWriter("values.txt");
out = new BufferedWriter(fstream);
// initialize the record count
int count = 0;
// create your iterator for your map
Iterator<Entry<Integer, String>> it = map.entrySet().iterator();
// then use the iterator to loop through the map, stopping when we reach the
// last record in the map or when we have printed enough records
while (it.hasNext() && count < recordsToPrint) {
// the key/value pair is stored here in pairs
Map.Entry<Integer, String> pairs = it.next();
System.out.println("Value is " + pairs.getValue());
// since you only want the value, we only care about pairs.getValue(), which is written to out
out.write(pairs.getValue() + "\n");
// increment the record count once we have printed to the file
count++;
}
// lastly, close the file and end
out.close();
}