Java text file operation

/*
 * Program Name:Student Information management program
 * Fuctions:
 *   *sort all records by student numbers
 *   *combine the student name and graduate college with "-"
 *   *convert the graduate date from format"yyyymmdd" to "dd/mm/yyyy"
 *   *cut the student tutor name into two strings
 *   *convert the number from format "100000.00" to "100,000.00"
 * Author:Sguy @ IBM Chengdu
 * Version:1.0
 * LastModified:2007/07/29
 * All rights reserved!
 */
package mainFolder;

//Head files for sortByStuNum
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.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.StringTokenizer;
//Head files for the Date format convert
import java.text.SimpleDateFormat;
import java.util.Date;
//Head files for the Number format convert
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;
import java.text.ParseException;

public class StuInforMan {
 
 //The program starts here
 public static void main(String args[])
 throws IOException
 {
  String sourceDataFile = "E://sguy_dev//StuInforProcess//mainFolder//StuInfor.txt";
        String targetDataFile = "E://sguy_dev//StuInforProcess//mainFolder//FinalOutputData.txt";
      
        //Define an instance of the StuInorMan,and call the informationProcess method
        StuInforMan stuInforMan = new StuInforMan();
        stuInforMan.informationProcess(sourceDataFile, targetDataFile);
 }
 /*
  * The Start of the block of records sorting
  */
 //The method convert a String variable to long type
 //from a record of the student data
 public static long numberTokenizer(String s)
    throws IOException
    {
        StringTokenizer st = new StringTokenizer(s,",");
        return Integer.valueOf((st.nextToken())).longValue();
    }
   
 //The method Sort records by student number
    public void informationProcess(String sourceDataFile,String bufferDataFile)  
    throws IOException
    {
     File sourceFile = new File(sourceDataFile);  
        File targetFile = new File(bufferDataFile);  
        /*
         *Check the source file and the buffer's validation
         */
        //confirm the source file's validation  
        if(!sourceFile.exists()) {  
            abort("no such source file: " + sourceDataFile);  
        }  
          
        if(!sourceFile.canRead()) {  
            abort("source file is unreadble: " + sourceDataFile);  
        }            
        //confirm the buffer file's validation
        if(targetFile.exists())
        {  
            if(!targetFile.canRead())
            {  
                abort("destination file is unreadble: " + bufferDataFile);  
            }
            // if the target file is overwritable?  
            System.out.println("Overwrite existing file " + targetFile.getName() +  " ? (Y/N):");  
            System.out.flush();
            //get user's response 
            BufferedReader userResponse = new BufferedReader(new InputStreamReader(System.in));
            String response = userResponse.readLine();
            if(!response.equalsIgnoreCase("y")) {  
                abort("existing file was not overwritable. ");  
            }  
        }
        /*
         *
         */
     long stuNumber = 0;
        String stuInfor = "";
        try
        {  
         DataArrayList dataArrayList = new DataArrayList();
           
         FileReader fileReader = new FileReader(sourceFile);
         FileWriter fileWriter = new FileWriter(targetFile);
         
         BufferedReader bufferReader1 = new BufferedReader(fileReader);
            while ((stuInfor=bufferReader1.readLine())!=null)
            {
               stuNumber=numberTokenizer(stuInfor);
               dataArrayList.add(stuNumber);    //add stuNumbers to the ArrayList
            }
            Collections.sort(dataArrayList);  //call the sort method
           
           
            DataMap dataMap = new DataMap();
            BufferedReader bufferReader2 =
                new BufferedReader(new FileReader(sourceDataFile));
            String stuInfor2 = null;
            while((stuInfor2=bufferReader2.readLine())!=null)
            {
             stuNumber=numberTokenizer(stuInfor2);
             StuInforMan stuMan = new StuInforMan();
             /*
              * This is String and Date and number format control block
              */
             
             StringTokenizer stringToken = new StringTokenizer(stuInfor2,",");
             
             String studentNumber = stringToken.nextToken();
             String studentName = stringToken.nextToken();
             String graduateCollege = stringToken.nextToken();
             String graduateTime = stringToken.nextToken();
             String studentTutor = stringToken.nextToken();
             String totalFees = stringToken.nextToken();
             //combine the two Strings with "-" between them
             String combinedString = studentName + "-" + graduateCollege;
             //split the third string into two strings with " & " between them
             //from the 5th char
             String splitString = stuMan.splitString(studentTutor, 5);
                //convert date format from "yyyymmdd" to "dd/mm/yyyy"
             String processedTime = stuMan.convertDate(graduateTime);
             //convert the number format from 10000.00 to 10,000.00
             String processedFees = stuMan.convertNumber(totalFees);
             //The final String written to the final output data text file
             String processedInfor = studentNumber + ","
                                + combinedString + ","
                                   + processedTime + ","
                                   + splitString + ","
                                   + processedFees;
             
                //get the final stuNumber and data reflect
                dataMap.putData(stuNumber,processedInfor); 
            }
           
            PrintWriter printWriter = new PrintWriter ( new BufferedWriter(fileWriter));
           
           
            Iterator it = dataArrayList.iterator();
            long tempLong = 0;
            String tempStr = "";
            while (it.hasNext())
            {
                tempLong = Integer.valueOf((String)it.next()).longValue();
                tempStr = dataMap.getData(tempLong);
                printWriter.println(tempStr);
               
            }
            System.out.println("The SORTED data has written to the target file!");
            printWriter.close();
        }catch(IOException e){
         System.out.println("The target file is unreachable!");
        }
    }
    //Show the detailed IO exception information
    private static void abort(String msg) throws IOException
    {  
        throw new IOException("DataProcess: " + msg);  
    }

    /*
     * Author Sguy @ IBM Chengdu
     * A Data Map that create a reflect with the student number
     * and the related detail information
     */
    class DataMap extends HashMap                
    {
        public void putData(long stuNumber,String stuInfor)
        {                           
            put(String.valueOf(stuNumber).toString(),stuInfor);
            //System.out.println("here is ok");
        }
        public String getData(long stuNumber)
        {
            String stuInfor = String.valueOf(stuNumber).toString();
            if (!containsKey(stuInfor))
            {
                System.err.println("Not found Key: "+stuInfor);
            }
            return (String)get(stuInfor);
        }
    }
    /*
     * Author Sguy @ IBM Chengdu
     * Sort by Student Number
     *
     */
    class DataArrayList extends ArrayList
    {
        public void add(long num)
        {
            String numToString = String.valueOf(num).toString();
            add(numToString);
        }
     }
   
    /*
     * This is the end point of the sort By Stu Number block
     */
   
    /*
     * This is the start point of String Split
     */
    public String splitString(String toBeSplit,int splitPosition)
    {
     //The length of the String is less than the splitPosition
     if(toBeSplit.length()<splitPosition)
     {
        System.out.print("The length of the String is less than the splitPosition:"+splitPosition);
        return toBeSplit;
        }
     else
     {
      byte bt[]=toBeSplit.getBytes();
      if(splitPosition > 1)  //Not just get the first char
      {
           if(bt[splitPosition]<0)  //if it's the chinese or japanese chracter
           {
              String substrx1 = new String(bt,0,--splitPosition);
              int i = splitPosition/2;
              String substrx2 = new String(bt,splitPosition,(toBeSplit.length() - i) * 2);
              String subStrs = substrx1 + " & " + substrx2;
              return subStrs; 
           }
           else
           {
              //The perfect condition,return the devided String
           String substrex1=new String(bt,0,splitPosition);
              String substrex2=new String(bt,splitPosition,toBeSplit.length() - splitPosition);
              String subStrs = substrex1 + " & " + substrex2;
              return subStrs;
           }
      }
      else
      {
           if(splitPosition==1)
           {
           if(bt[splitPosition]<0)
              {
                 //just cut one chinese or japanese charater
              String substr1 = new String(bt,0,++splitPosition);
                 String substr2 = new String(bt,splitPosition,(toBeSplit.length()-1)*2);
                 System.out.println(toBeSplit.length());
                 String subStrs = substr1 + " & " + substr2;
                 return subStrs;
              }
           else
              {
                 //Just cut the first one char down,and return it
              String subStr1 = new String(bt,0,splitPosition);
              String subStr2 = new String(bt,splitPosition,toBeSplit.length()-splitPosition);
              String subStrs = subStr1 + " & " + subStr2;
                 return subStrs;
             }
           }
           else
           {
               System.out.println("The splitPosition must be an integer larger or equal than 1");
               return toBeSplit;
           }
       }
        }
    }  //Here is the end of the String Split method
   
    /*
     * Here is the The start point of the Date format convert method
     */
    public String convertDate(String toConvertDate)
    {
        //Create a date formatter that can parse dates of
        //the format yyyymmdd.
     SimpleDateFormat inputDateFormat = new SimpleDateFormat("yyyymmdd");
     //the form DD-MM-YYYY
     SimpleDateFormat outputDateFormat = new SimpleDateFormat("dd/mm/yyyy");
     //Create a string containing a text date to be parsed.
     String dateParsedString = null;
     try
     {
      //Parse the text version of the date.
         Date date = inputDateFormat.parse(toConvertDate);
         //Now convert the date format from the input format to the
         //output format
         dateParsedString = outputDateFormat.format(date);
         return dateParsedString;
        
     }catch (Exception ex)
     {
         System.out.println("The text format can not convert to a Date format,please check the data file");
         System.out.println("Here is the detail information about the exception:");
      System.out.println(ex.getMessage());
         return null;
     }
     }  //Here is the end point of the date format convert method
    public String convertNumber(String toConvertNumber)
    {
     Object object = null;
     DecimalFormat decimalFormat = null;
        //get a NumberFormat object and convert it to a DecimalFormat Object
        try
        {
         decimalFormat = (DecimalFormat) NumberFormat.getInstance(Locale.US);
         object = decimalFormat.parse(toConvertNumber);
        }
        catch (ClassCastException e)
        {
            System.err.println(e);
        }
        catch (ParseException e2)
        {
            System.out.println("Please check the data file,mack sure you are processing a number!");
            System.out.println("Here is the detail information about this exception:");
            System.err.println(e2);
        }
        // Define the number format
        decimalFormat.applyPattern("#,###.000000");
        // format a number
        return decimalFormat.format(object);
    }
}