Swing Hacks

Export Table Data to an Excel Spreadsheet #25

Chapter 3, Tables and Trees

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131

HACK

Dealing with Formatting

Excel uses a complicated database-oriented format for its native .xls files.

This format defines the formulas, colors, charts and every other advanced

feature Excel has supported over the years. Writing to the native .xls format

is complicated but, fortunately, Excel supports other formats. The one I’m

going to target is known as a tab-delimited text file, so called because tabs

separate each field. This format is just plain text, so it will be super easy to

write from Java, and open up in Excel with just a double-click.

Tab-delimited files separate each field with a tab character and each row

with a standard Unix line break,

\n

. Since Swing defines a convenient

getValueAt( ) method in the TableModel interface, it’s very easy to just loop

through the table cells and write it out to a file, as seen in Example 3-14.

This code defines an

ExcelExporter class with a single method exportTable( ),

taking a

JTable and a file. All JTables contain an implementation of the

TableModel interface that holds the actual data. The code first retrieves the

table model and opens a new

FileWriter to the file. I used a FileWriter

instead of a FileOutputStream because Writers automatically handle text

encoding issues. This means you don’t have to worry about the language the

program is running on. Using a

Writer ensures ...