----------------------------------------tips.tricks.html 8. Support for large reports For filling and exporting large documents that would normally eat up memory and crash with an OutOfMemory exception, there is now a new feature called "report virtualizer" that uses serialization of temporary data on disk to optimize memory consumption. This can be seen in action in the supplied /demo/samples/virtualizer sample provided. This new feature is a contribution from Works Inc. ------翻译 -------当填充和输出大数据量的报表时,它会耗净我们的内存并且报OutOfMemory的异常.现在有一个新的特性叫"report virtualizer"可以用来序列化临时数据到硬盘上来优化内存的使用. 我们可以在 /demo/samples/virtualizer 上看到它的使用,它是由Works Inc来开发的. ......... JRFileVirtualizer virtualizer = new JRFileVirtualizer(2, "tmp"); ..... // Preparing parameters Map parameters = new HashMap(); parameters.put(JRParameter.REPORT_VIRTUALIZER, virtualizer); JasperPrint jasperPrint = JasperFillManager.fillReport(fileName, parameters, dataSource); virtualizer.setReadOnly(true); .......... 另:看到几个有用的 net.sf.jasperreports.view.JasperDesignViewer 可以直接浏览xml 或jasper的设计图
