getting null pointer exception! how to fix it.

[Rahul Shilpakar]

there is a text file having data in rows and column with positoning the tabs and \n . i am getting all rows. now the first element in row is a primary key in a (DB) table. and i want to do the operations on the other column.

Problem is that when i retrives a row, at last its showing null charecter or space type.

         text file like this
         -------------------------------------------
         |123    4     30     no$   0
         |124    9     90     no$   0
         |

now for 124 id. its primary key in a table master table. and other column in mastertable having primary key 124 is its name.

Am splitng a row on "\t" string and store in String array
now it gives total 6 values in string array 123, 4, 30, no$, 0 and last is null i.e. nothing

my code is

DefaultSupString uses searchrecord class

package supstring;
 
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import dbmanager.DBManager;
import java.sql.*;
import java.util.Hashtable;
import java.util.Vector;
 
public class DefaultSupString {

String path = "D:\\Reports\\Basic_Reports\\Master_Reports\\25\\25_pv.txt";
DBManager db;
String sqlTable = "master_table";
ResultSet rs;

String supstr;

void itemaspv(){
try{

SearchRecord sr = new SearchRecord(path);
sr.getRecordSet();
}
catch(Exception e){
e.printStackTrace();
}
}

String getSupplierString(String[] arr){
try{

db.getConnect();
String query = "select Name from "+sqlTable+" where id="+arr[0];
ResultSet rs = db.getSelect(query);

if (rs.next()){
String tempstr = rs.getString("Name");
String splititemname [] = tempstr.split("\t");
if (splititemname[0].length()<15){
supstr = splititemname[0];
}
else{
supstr = splititemname[0].substring(0, 14);
}
supstr = supstr+splititemname[splititemname.length-1]+splititemname[splititemname.length];
System.out.println(supstr);
}
}
catch(Exception e){
e.printStackTrace();
}
return supstr;
}
public static void main(String[] args) {
DefaultSupString dss1 = new DefaultSupString();
dss1.itemaspv();
}
}
 
----------------------------------------------
searchrecord.java
 
package supstring;
 
import java.io.*;
import java.util.*;
 
import dbmanager.Column;
 
 
public class SearchRecord 
{
String Path;
DefaultSupString dss;

public SearchRecord(String Path)
{
this.Path = Path;
}

public void getRecordSet()
{
    try{
    RandomAccessFile random = new RandomAccessFile(Path,"r");
random.readLine();

while(random.read() != -1){

random.seek(random.getFilePointer()-1);
String src=random.readLine();

System.out.println("The Line is : " +src);
String[]arr2=src.split("\t");

//int masternameid = Integer.parseInt(arr2[0]);
int temp = Integer.parseInt(arr2[1]); 

if (temp==9){
dss.getSupplierString(arr2);
}
}
    }
catch(Exception e){
e.printStackTrace();
}
}
}
 

-------------
Exception

java.lang.NullPointerException
at supstring.SearchRecord.getRecordSet(SearchRecord.java:37)
at supstring.DefaultSupString.itemaspv(DefaultSupString.java:24)
at supstring.DefaultSupString.main(DefaultSupString.java:58)

[ UD: added CODE tags ]
[ July 14, 2007: Message edited by: Ulf Dittmer ]

[Rahul Shilpakar]

MORE elaborate about my test file presentation

my_text_file.txt
-------------------------------------------------------
| mid pid pv vt Ref FD TD
| 123 9 25 no$ 0
| 124 9 25 no$ 0
| 125 9 25 no$ 0
| :
| :
| :
|

Problem: I am storing one row in string array
i.e. String arr2[]={123,9,25,no$,0, , ,}.There is nothing in column FD & TD

Now, how can avoid vlaues of FD TD to eliminate NullpointerException.?

its giving exception in file Searchrecord.java file
at
if (temp==9){
dss.getSupplierString(arr2); // here am getting problem

}

please tell me . i am in need.
[ July 14, 2007: Message edited by: Rahul Shilpakar ]

[Stan James]

I think you just need to check each array entry for null before using it:

if (arr[i] != null)
   do something with arr[i]

Depending on your business rules, you can sometimes plug in a default value. Right after your split() you might fill in defaults:

if ( arr[0] == null ) arr[0] = "";
if ( arr[1] == null ) arr[1] = new Date();
if ( arr[2] == null ) arr[2] = new Integer(0);
etc.

This is probably outsid ethe bounds for the beginner forum, but some times we can provide a special object that defines the behavior for missing data.

if ( arr[3] == null ) arr[3] = new NoSuchPerson();

That can avoid repetitive tests and lame comments in later code.

// replace
if( person == null ) // no such person
   name = "Not Found"
else
   name = person.getName();
 
// with
name = person.getName();

Any of those ideas work for you?
[ July 15, 2007: Message edited by: Stan James ]