将JasperReports与相对路径一起使用 [英] Using JasperReports with a relative path

问题描述

我有一个网络应用程序，客户端已要求查看一些报告。方法是使用iReport并在屏幕上显示报告。

I have a web app and the client has requested to see some reports. The approach has been to use iReport and show them the report on screen.

我已经问了这样的事情。但今天我发现报告文件（jrxml）的路径是绝对的。所以我必须改变程序，以便接受相对路径。我一直在尝试这样做，但似乎jrxml或编译（.jasper）文件都不接受既不编译也不填充报告的相对路径。

I have already asked something like this. But today I have discovered that the paths to the report files (jrxml) are absolute. So I have to change the program so it accepts relative paths. I have been trying to do this, but it seems that neither the jrxml or the compiled (.jasper) files accepts relative paths to neither compile or to fill the report.

这就是我迄今为止所做的：

This is what I have got this far:

//path is generated as request.getContextPath() + "/jrxmlFiles/"
public void generateReport(HttpServletResponse res, ConexionAdmin con, String path) throws Exception{ 

    ServletOutputStream out = null;
    ByteArrayOutputStream bos    = new ByteArrayOutputStream();

    JasperDesign jasperDesign = JRXmlLoader.load(path);
    JasperReport jasperReport = JasperCompileManager.compileReport(jasperDesign);

  byte[] bytes = JasperRunManager.runReportToPdf(jasperReport, pars, con.initConexion());
        res.setContentType("application/pdf");
  res.setContentLength(bytes.length);
  out = res.getOutputStream();
  out.write(bytes, 0, bytes.length);

  res.setHeader("Cache-Control", "cache");
  res.setHeader("Content-Disposition", "attachment; filename=report.pdf"); 
  res.setHeader("Pragma", "cache");
  res.setContentLength(bos.size());

  out.write(bos.toByteArray());
  out.flush();
  bos.close();
  out.close(); 
  res.flushBuffer();
}

这似乎适用于绝对路径，但却让我感激不尽：

This seems to work with absolute paths, but throws me:

Exception Message
net.sf.jasperreports.engine.JRException: java.io.FileNotFoundException

更改为相对路径时。我在网上搜索没有成功如何改变我的适合度。

when changed to a relative path. I have searched the net with no success in how to change to my fits.

我有jasper API的javaDoc，但如果我能帮助它，我宁愿不读它。

I have the javaDoc for the jasper API, but I rather not read it through if I can help it.

推荐答案

• 路径必须是绝对路径。


• 仅编译 .jrxml 文件到 .jasper 文件，如果 .jrxml 正在修改。通常，您只需加载 .jasper 文件并完全跳过编译。它要快得多。


• 存储 .jasper 和 .jrxml 以外的文件你的网络根目录。


• 在你的所有报告中创建以下参数：
  • Paths must be absolute.
  • Only compile .jrxml files to .jasper files if the .jrxml is being modified. Usually you can just load the .jasper file and skip compilation altogether. It is much faster.
  • Store .jasper and .jrxml files outside of your web root.
  • Create the following parameters throughout all your reports:

    
       ROOT_DIR = "/full/path/to/reports/"
       IMAGE_DIR = $P{ROOT_DIR} + "images/"
       STYLES_DIR = $P{ROOT_DIR} + "styles/"
       SUBREPORT_DIR = $P{ROOT_DIR} + "subreports/"
       COMMON_DIR = $P{ROOT_DIR} + "common/"

  
  
  • 参考项目相对于 $ P {ROOT_DIR} （例如， $ P {IMAGE_DIR} 是根据 $ P {ROOT_DIR} 来定义的。
  
  
  • 从您的环境中传递 $ P {ROOT_DIR} 的值。
  
  
  • 松散地结合你的应用于您使用的任何报告框架。
  
  
  • Reference items relative to $P{ROOT_DIR} (e.g., $P{IMAGE_DIR} is defined in terms of $P{ROOT_DIR}).
  • Pass the value of $P{ROOT_DIR} in from your environment.
  • Loosely couple your application to any reporting framework you use.

  然后在必要时使用表达式。例如，引用子报告如下：

  Then use the expressions when necessary. For example, reference subreports as follows:

  <subreportExpression>
    <![CDATA[$P{SUBREPORT_DIR} + "subreport.jasper"]]>
  </subreportExpression>
  

  这将允许子报告目录在不同环境之间变化。

  This will allow the subreport directory to vary between environments.

  这篇关于将JasperReports与相对路径一起使用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！