ResultSet Data

CSV Manager can load and save your data as a JDBC ResultSet.

Code Example

File              csvfile = new File("mydata.csv");
CsvManager        csvman  = new CsvManager();
csvman.getCsvSpec().setProperty( "ResultSet.dataHasHeaders", true );
ResultSet         rs      = csvman.loadResultSet( csvfile );
ResultSetMetaData md      = rs.getMetaData();
int               numCols = md.getColumnCount();

for( int col = 1; col <= numCols; col++ ) {
  System.out.print( md.getColumnName(col) + (col<numCols?", ":"\n") );
}
while( rs.next() ) {
  for( int col = 1; col <= numCols; col++ ) {
    System.out.print( rs.getString(col) + (col<numCols?", ":"\n") );
  }
}

This code example loads the data in a CSV file into an object which implements the ResultSet interface.

Use this method when...

• you want all the data in memory.
• your data has standard columns.
• you need to pass the CSV data to code that already uses ResultSets.
• you want to make use of type conversion methods like getInt().

What happens when some rows contain more fields than others?

You can only access extra fields if you know they are there. CSV Manager returns the number of data fields found in the first row via the ResultSetMetaData interface, and assumes that this defines the number of fields in the CSV file. But you can still access extra data fields directly by using field index values that are greater than the default number of fields in the ResultSet get methods. But like a normal ResultSet, if you try to access a data field that does not exist, an exception will be thrown.

What happens when some rows are missing fields?

CSV Manager keeps track of the default number of data fields that you expect in your CSV file (you can set the default number of fields, or let CSV Manager automatically use the number of fields in the first row). When fields are missing, the ResultSet assumes that they are empty strings.

OK, how do I get the column headers?

CSV Manager also implements the ResultSetMetaData interface. Assuming the headers are in the first line of the CSV file, you can access them via the standard methods of ResultSetMetaData such as getColumnCount and getColumnName. If the column names are not in the first line, then they are either in a predefined line (say line 3), so start loading lines from there using setStartLine, or you can set CSV Manager to ignore empty lines, until you find them.

But my data isn't in a file!

You are not restricted to loading CSV data only from files. You can also load data from Strings (loadFromString(String) method) and from InputStreams (load(InputStream) method). This means that you can use CSV Manager in a completely dynamic way within your application.

What about saving data to a CSV file?

You can also save data to a CSV file using a ResultSet. Connect to your database, run a query, and then hand the ResultSet over to CsvManager to save as a CSV file. Here's the example code:

File       csvfile = new File("mydata.csv");
CsvManager csvman  = new CsvManager();
Connection con     = getDatabaseConnection(); // return a java.sql.Connection

// assume a Product table in database
PreparedStatement ps  
   = con.prepareStatement( "SELECT * FROM Product" ); 

ResultSet rs = ps.executeQuery();
csvman.saveResultSet( csvfile, rs );

CSV Manager can use the ResultSetMetaData object from the database ResultSet to output column headers. See the save method description for more details.

What other data structures can you handle?

We also support:

• StringArrays
• List of Lists
• TableModels
• Event-driven Data
• Streaming Data

I need to see something working.

Sure, no problem. Head on over to our online demo and try out CSV Manager on your own data.

I have another question...

If you have a particular question you need answered, just ask! We're happy to explain exactly how CSV Manager works and show you how to use it.