Urgent Help needed with nulls from ResultSet

[stressball]

I am getting data from a ResultSet and putting it into a Hashtable. My problem is that some of the fields I am getting back are null, but I still need them. I would like to change them to an empty String, currently I am doing this but I would like to create a method to test if there is a null field in the ResultSet and set it to an empty String. I need to do this without specifying a column name as there are many columns and many could be null. Here is an example of one of the many if statements I currently have:

Hashtable finalContentHash = new Hashtable();
P_Content_Read contentRead = new P_Content_Read();
ResultSet rs = contentRead.getData(content_id);
String handleNull = "";

if (rs.getObject(DEFAULT_FILE)!=null) {
finalContentHash.put(DEFAULT_FILE_TITLE,rs.getObject(DEFAULT_FILE)); } else
finalContentHash.put(DEFAULT_FILE_TITLE,handleNull);

Can somebody help me?! I would like to use column numbering eg
loop through resultset checking for nulls and replacing them with "" but I can't seem to get it working.

Your help will be most appreciated.

 

[wushutwist]

Tricky things about resultsets is that you have to get the object before you can tell if it is null. Example:

Hashtable finalContentHash = new Hashtable();
P_Content_Read contentRead = new P_Content_Read();
ResultSet rs = contentRead.getData(content_id);
String handleNull = "";

Object o;
o = rs.getObject(DEFAULT_FILE);
if (rs.wasNull) 
  finalContentHash.put(DEFAULT_FILE_TITLE,handleNull);
else
  finalContentHash.put(DEFAULT_FILE_TITLE,o);

Here is the API for wasNull() FYI:

wasNull

public boolean wasNull()
                throws SQLException


Reports whether the last column read had a value of SQL NULL. Note that you must first call one of the getXXX methods on a column to try to read its value and then call the method wasNull to see if the value read was SQL NULL.

Returns:

true if the last column value read was SQL NULL and false otherwise

Throws:

SQLException - if a database access error occurs

Wushutwist

 

[stressball]

Thank you Wushutwist BUT...
I need a generic way of dealing with the nulls in my ResultSet.
There are 7 columns that may be null. I do not want to keep 7 If statements that do the the same thing for each column. I want a method that gets the ResultSet, searches for nulls and replaces the nulls with an empty String.

Help please, I can't seem to find any documentation on this and my attempts are failing miserably!

 

[LeonTang]

Hi, I think this would help:-

...
Hashtable finalContentHash = new Hashtable();
P_Content_Read contentRead = new P_Content_Read();
ResultSet rs = contentRead.getData(content_id);
ArrayList rsList = convertData(rs);
// loop through rsList to retrieve the data just like looping through resultset
...

public ArrayList convertData(ResultSet rs)
{
// get number of columns
int col = rs.getMetaData().getColumnCount();
ArrayList rsList = new ArrayList();

// transfer data to arraylist
while (rs.next())
{
String temp = "";
for (int i=0;i<col;i++)
{
String s = (String)rs.getObject(i);
if (s != null)
temp = temp + s + &quot; &quot;;
else
temp = temp + &quot; &quot;;
}
rsList.add(temp);
}
return rsList;
}


It should be something like this. I have not tested it out so I am not sure if it would work or not but the idea should be there.

Regards,
Leon