Byte arrays and In/Out Stream usage help

[2005 IR Help]

By: David Lim - aberrant80

Byte arrays and In/Out Stream usage help

2004-03-11 02:40

I don't know very much about in/out streams so I don't really understand how to use these data types with JasperReports. I would appreciate it if someone could enlighten me on their usage and maybe give a quick example code.

 

For one, I'm wondering if I could actually do the file writing within my own code, rather than relying on Jasper's various managers to do the writing for me. How can I actually make use of the btye arrays returned by JasperRunManager, or the output streams in the arguments to help me save to a local file?

 

Thanks in advance. Any guidance appreciated.

 

 

 

 

By: Chuck Deal - cdeal

RE: Byte arrays and In/Out Stream usage help

2004-03-11 08:14

Take a look at the managers that exist. The *Manager classes are designed to help out developer's by doing the common things. They don't work in ALL cases, but they do work for most. Particularly, in your case look at the Export Manager and you might get an idea of how to manage the outputstream used by the exporter.

 

 

 

 

By: Carlos Costa e Silva - carloscs

RE: Byte arrays and In/Out Stream usage help

2004-03-11 10:21

Here is an example of using in/out streams:

 

final String jasperFile = "Report.jasper";

final URL inUrl = ClassLoader.getSystemResource(jasperFile);

if (inUrl == null) {

throw new IOException("File Report.jasper not found.");

}

final File pdfFile = new File("Report.pdf");

 

InputStream in = null;

OutputStream out = null;

try {

in = inUrl.openStream();

out = new BufferedOutputStream(new FileOutputStream(pdfFile));

 

JasperRunManager.runReportToPdfStream(in, out, parameters, connection.getDatabaseConnection());

}

finally {

if (in != null) {

in.close();

}

if (out != null) {

out.close();

}

}

 

 

For managing yourself the output, use

 

byte[] byteArray = JasperManager.whateverToByteArray(...)

 

and every outptut stream has write(byte[] b) and write(byte[] b, int off, int len) methods.

 

 

 

 

 

 

By: MonkeyJoe - monkeyjoe

RE: Byte arrays and In/Out Stream usage help

2004-03-11 11:40

Or this if you want to generate pdf in a web app

----------------------------------------------

 

ServletContext context = request.getSession().getServletContext();

File reportFile = new File(context.getRealPath("report/student_audit_report.jasper"));

 

try {

 

byte[] bytes = JasperRunManager.runReportToPdf(

reportFile.getPath(),

parameters,

new JREmptyDataSource());

 

response.setContentType("application/pdf");

response.setContentLength(bytes.length);

ServletOutputStream ouputStream = response.getOutputStream();

ouputStream.write(bytes, 0, bytes.length);

ouputStream.flush();

ouputStream.close();

 

 

} catch (JRException e) {

e.printStackTrace(); //To change body of catch statement use Options | File Templates.

}

 

 

 

enjoy!

 

m

 

 

 

 

By: David Lim - aberrant80

RE: Byte arrays and In/Out Stream usage help

2004-03-11 17:54

Hmmm... I'll try them out. Thanks alot!