read from file and store using hash map

read from file and store using hash map

I was stuck with a java project where I have to read a file with two different concepts and store them differently in hashmap. My data file would be something like

Adults:

Name, xyz (Key, value)
ID, 123 (key, value)

Children:

Name, abc
ID, 321 and so on........

Here two concepts adults and children in file should be stored in two different maps. Any help will be appreciated. Thanks in advance.

View Answers

July 25, 2012 at 12:30 PM

Here is a simple example of storing the text file data into HashMap.

import java.io.*;
import java.util.*;
class OnlyExt implements FilenameFilter{
  String ext;
  public OnlyExt(String ext){
  this.ext="." + ext;
  }
  public boolean accept(File dir,String name){
  return name.endsWith(ext);
  }
}
class MapExample{
    public static void main(String[] args)throws Exception{
        FilenameFilter ff = new OnlyExt("txt");
        File folder = new File("c:/");
        File[] files = folder.listFiles(ff);
        Map<String,String> map=new LinkedHashMap<String,String>();
        for(int i=0;i<files.length;i++){
        FileReader fr = new FileReader(files[i].getPath());
            BufferedReader reader = new BufferedReader(fr);
            String st = "",str=" ";
            while((st = reader.readLine()) != null) {
        str+=st;
        }
        map.put(files[i].getName(),str);
        }
        Set set = map.entrySet();
        Iterator i = set.iterator();
        while(i.hasNext()){
        Map.Entry me = (Map.Entry)i.next();
        System.out.println(me.getKey() + " \t:\t " + me.getValue());
    }
  }
}

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