Try something like:
Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
c = DriverManager.getConnection( "jdbc:odbc:excel_dsn", "", "" );
stmnt = c.createStatement();
String query = "select * from [main$] where [Field1]='
Test';";
ResultSet rs = stmnt.executeQuery( query );
With a DSN of "excel_dsn" pointing to your Excel workbook file.