iReport: Load Subreport From Database

问题

I have report that uses a subreport, but since the subreport is stored in a database table as BLOB, I cannot give its path (url) in the *.jrxml file. Is there a way to add a *.jasper file loaded from the database (BLOB or InputStream) as a subreport.

回答1:

I figured it out.

1. Add a list component
2. In the list's dataset fetch the field you keep your subreport as a BLOB, lets call it REPORT_DATA.
3. Set REPORT_DATA field's type to InputStream.
4. Add the subreport inside the list.
5. Set "Subreport Expression" to $F{REPORT_DATA} and its "Expression Class" to InputStream.
6. Set Connection type, expression, and parameters accordingly.

Don't forget to resize the list component at least to the subreport's size, otherwise you get an error like :

net.sf.jasperreports.engine.design.JRValidationException: Band height validation for subreport ...

来源：https://stackoverflow.com/questions/23082712/ireport-load-subreport-from-database