import java.awt.List; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; public class Main { public static void main (String[] args) throws IOException{ BufferedWriter writer = new BufferedWriter(new FileWriter(new File("/Users/hakuri/Desktop/data2.txt"))); BufferedReader reader=new BufferedReader(new FileReader(new File("/Users/hakuri/Desktop/final.txt"))); String lineTxt = null; int i=1; // ArrayList brand = new ArrayList(); HashMap custom=new HashMap(); while((lineTxt = reader.readLine()) != null){ //System.out.println(lineTxt); String line=lineTxt.trim(); String[] part=line.split(","); if(!custom.containsKey(part[0])){ custom.put(part[0],new ArrayList()); custom.get(part[0]).add(part[1]); } else{ custom.get(part[0]).add(part[1]); } // custom.put(part[0], part[1]); } //System.out.print(custom); Iterator it=custom.keySet().iterator(); while( it.hasNext()){ String key=(String)it.next(); ArrayList value=custom.get(key); System.out.println(key+"--"+value); } //System.out.println(custom.keySet().iterator()); } }