Creating a CSV File in java from a HashMap

Question

I have a hashMap in java in terms of some keys which each key is indicating a flow. Then each value showing statics about each packet belongs to that flow.

What I need t

Answer 1

You can use from following API's.

POI : http://poi.apache.org

javacsv : http://sourceforge.net/projects/javacsv

JExcel : http://jexcelapi.sourceforge.net/

opencsv : http://opencsv.sourceforge.net/

Following is writting to csv example using supercsv api:

import java.io.FileWriter;
import java.util.HashMap;
import org.supercsv.io.*;
import org.supercsv.prefs.CsvPreference;

public class CSVWriteExample {

    /**
     * @param args
     */
    public static void main(String[] args) throws Exception{  

      ICsvMapWriter writer = new CsvMapWriter(new FileWriter("person.csv"), CsvPreference.EXCEL_PREFERENCE);  
      try {  
        final String[] header = new String[] { "name", "city", "pin" };  
        // set up some data to write  
        final HashMap data1 = new HashMap();  
        data1.put(header[0], "Raj");  
        data1.put(header[1], "Vijayawada");  
        data1.put(header[2], 500026);  
        final HashMap data2 = new HashMap();  
        data2.put(header[0], "Suneel");  
        data2.put(header[1], "Tenali");  
        data2.put(header[2], 522202);  

        // the actual writing  
        writer.writeHeader(header);  
        writer.write(data1, header);  
        writer.write(data2, header);  

        System.out.println("Writing Completed...!");  
      } finally {  
        writer.close();  
      }  
 }
}

Also realted questions on stackoverflow can be found :

Can you recommend a Java library for reading (and possibly writing) CSV files?

CSV API for Java