用数据填充它.dataSource 是您拥有的 DataSource 实例 - 例如一个 BeanCollectionDataSource

Fill it with data. dataSource is the DataSource instance you have - for example a BeanCollectionDataSource

JasperPrint jasperPrint = 
     JasperFillManager.fillReport(jasperReport, params, dataSource);

导出

Export it

JRPdfExporter exporter = new JRPdfExporter();
exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, outputStream);
exporter.exportReport();

上面的 outputStream 可以是 response.getOutputStream() 或 FileOutputStream()，这取决于你是否想要将其发送给客户端，或者您想将其存储为文件.如果要将其发送给客户端，则必须发送 Content-Disposition 标头，以及其他一些标头，但这取决于要保存的格式.如果您想在客户端打印，这是一个完全不同的问题 - 您需要一些客户端代码，例如一个小程序.

The outputStream above may be either a response.getOutputStream() or a FileOutputStream(), depending on whether you want to send it to a client or you want to store it as a file. If you want to send it to the client, you'd have to send the Content-Disposition header, and some more, but that depends on the format you want to save to. In case you want to print on the client, it's quite a different question - you'd need some client-side code, an applet, for example.