parsing - How to check for duplicate records in .csv using java -

i have csv file:

10;name1;id1 20;name2;id2 10;name3;id3 

row row push data method called forward:

forward(nr, name, id);

how can check whole csv if "nr" duplicate? in above example is: 10.

my code now:

while ((line = reader.readline()) != null) {     scanner = new scanner(line);     scanner.usedelimiter(";");     while (scanner.hasnext()) {         string data = scanner.next();         if (index == 0)             nr = integer.parseint(data);         else if (index == 1)             name = data;         else if (index == 2)             id = data;         else             system.out.println("invalid data::" + data);         index++;     }     index = 0;     forward(nr, name, id);   } 

if duplicate found, want print on screen.

use map<long, string>. each time before forward output can check if map contains key (the number) already.

map<long, string> entrymap = new hashmap<long, string>(); [...] if (!entrymap.containskey(nr)) {      entrymap.put(nr, name);      forward(nr, name, id); } else       system.out.println("entry number " + nr + " added .csv file"); 

if number relevant , don't need put exceptions (e.g., entry name , number in file), might want choose other data structures, e.g., list.

as read in comments above, if replacing intention following:

create class keeps parameters:

public class csventry {        private int number;        private string name, id;         public csventry(number, name, id) {            this.number = number;            this.name = name;            this.id = id;        }        // getters & setters } 

and change map to:

map<long, csventry> entrymap = new treemap<long, csventry>(); // treemap entries sorted. [...] entrymap.put(nr, new csventry(nr, name, id)); // after populating map, e.g., after outer loop forward(entrymap); 

and in forward loop map output.