Create reports

An Excel report is generated from

• Jxls options,
• the Jxls template and
• data.

Since version 3, the options are put together with the new JxlsTemplateFillerBuilder with a fluent API.

The template is then added using a withTemplate() method.

Call build() and fill(data, outputFile) for creating an Excel report.

Map<String, Object> dataMap = new HashMap<>(); // and fill dataMap...
JxlsTemplateFiller filler = JxlsPoiTemplateFillerBuilder.newInstance()
    // builder options...
    .withTemplate("filename.xlsx")
    .build();
filler.fill(dataMap, new JxlsOutputFile(new File("report.xlsx")));

Or shorter:

Map<String, Object> dataMap = new HashMap<>(); // and fill dataMap...
JxlsPoiTemplateFillerBuilder.newInstance()
    // builder options...
    .withTemplate("filename.xlsx")
    .buildAndFill(dataMap, new File("report.xlsx"));

Data

The data is passed to Jxls as a single Map<String, Object> object. A map value can be a scalar, an Iterable, an array or an object. Scalar: String, Double, boolean and so on. Object can be a POJO class or a Map<String, Object>. Jxls must be able to add entries to the map and remove entries from the map.

In version 2 Jxls used a class called Context that held a Map<String, Object>. In version 3 we have simplified it to Map<String, Object> and call this object 'data map'.

Common options

Common options are streaming and throwing exceptions. And it's recommended to use permissions.

JxlsPoiTemplateFillerBuilder.newInstance()
    .withExceptionThrower()
    .withExpressionEvaluatorFactory(new ExpressionEvaluatorFactoryJexlImpl(
        false, true, JxlsJexlPermissions.RESTRICTED))
    .withStreaming(JxlsStreaming.AUTO_DETECT)
    .withTemplate("filename.xlsx")
    .buildAndFill(dataMap, new JxlsOutputFile(new File("report.xlsx")));

If you want to use SLF4J for logging you must replace withExceptionThrower() by withLogger(new Slf4jJxlsLogger()) and copy the class from the SLF4J page.

Real world production scenario

In real world production scenario you want to have a stable codebase. You can't deliver every day. It should be possible just to change a template file. So it's a philosophy to have as much as possible inside the template files.