Jasper Reports + Web App + HTML Reports

我会带着你远行 2022-01-15 13:19 223阅读 0赞

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## [Jasper Reports + Web App + HTML Reports][Jasper Reports _ Web App _ HTML Reports] ##

by [deepak][] on Jan.20, 2011, under [Jasper Reports][]

I had lots of difficulties in getting HTML reports to work in my web application. When I added a couple of images in the report, I could see them when exporting the report to PDF, but could not see the images when exported to HTML. All I could see was a bunch of broken images !

Here is how to solve this issue.

In the web.xml file add the following entry:

<table style="border:0px;text-align:left;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;"> 
 <tbody> 
  <tr> 
   <td style="border:0px;vertical-align:baseline;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;color:#AFAFAF;"> 
    <div>
      1 
    </div> 
    <div>
      2 
    </div> 
    <div>
      3 
    </div> 
    <div>
      4 
    </div> 
    <div>
      5 
    </div> 
    <div>
      6 
    </div> 
    <div>
      7 
    </div> 
    <div>
      8 
    </div> 
    <div>
      9 
    </div> </td> 
   <td style="border:0px;vertical-align:baseline;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;"> 
    <div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>&lt;</code> 
      <code>servlet</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>&lt;</code> 
      <code>servlet-name</code> 
      <code>&gt;ImageServlet&lt;/</code> 
      <code>servlet-name</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>&lt;</code> 
      <code>servlet-class</code> 
      <code>&gt;net.sf.jasperreports.j2ee.servlets.ImageServlet&lt;/</code> 
      <code>servlet-class</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&lt;/</code> 
      <code>servlet</code> 
      <code>&gt;</code> 
     </div> 
     <div>
       &nbsp; 
     </div> 
     <div> 
      <code>&lt;</code> 
      <code>servlet-mapping</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>&lt;</code> 
      <code>servlet-name</code> 
      <code>&gt;ImageServlet&lt;/</code> 
      <code>servlet-name</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>&lt;</code> 
      <code>url-pattern</code> 
      <code>&gt;/servlets/image&lt;/</code> 
      <code>url-pattern</code> 
      <code>&gt;</code> 
     </div> 
     <div> 
      <code>&lt;/</code> 
      <code>servlet-mapping</code> 
      <code>&gt;</code> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

The part in your code where you export the report to HTML should look like this.

<table style="border:0px;text-align:left;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;"> 
 <tbody> 
  <tr> 
   <td style="border:0px;vertical-align:baseline;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;color:#AFAFAF;"> 
    <div>
      1 
    </div> 
    <div>
      2 
    </div> 
    <div>
      3 
    </div> 
    <div>
      4 
    </div> 
    <div>
      5 
    </div> 
    <div>
      6 
    </div> 
    <div>
      7 
    </div> 
    <div>
      8 
    </div> 
    <div>
      9 
    </div> 
    <div>
      10 
    </div> 
    <div>
      11 
    </div> </td> 
   <td style="border:0px;vertical-align:baseline;font-family:Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace;font-size:1em;"> 
    <div> 
     <div> 
      <code>JRHtmlExporter htmlExporter = </code> 
      <code>new</code> 
      <code>JRHtmlExporter();</code> 
     </div> 
     <div>
       &nbsp; 
     </div> 
     <div> 
      <code>// without the below line , images will not appear in the HTML report</code> 
     </div> 
     <div> 
      <code>session.setAttribute(ImageServlet.DEFAULT_JASPER_PRINT_SESSION_ATTRIBUTE,</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>filledReport);</code> 
     </div> 
     <div> 
      <code>htmlExporter.setParameter(JRExporterParameter.JASPER_PRINT,</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>filledReport);</code> 
     </div> 
     <div> 
      <code>htmlExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, baos);</code> 
     </div> 
     <div> 
      <code>htmlExporter.setParameter(JRHtmlExporterParameter.IMAGES_URI,</code> 
     </div> 
     <div> 
      <code>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</code> 
      <code>"../servlets/image?image="</code> 
      <code>);</code> 
     </div> 
     <div> 
      <code>htmlExporter.exportReport();</code> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

Make sure that you set the path to the image servlet right in the JRHtmlExporterParameter.IMAGES\_URI parameter.  
As mention in the code comments, the most important step is to set the ImageServlet.DEFAULT\_JASPER\_PRINT\_SESSION\_ATTRIBUTE in the session to the JasperPrint object. If you do not set this, you will see the following exception when you access /servlets/image in the browser:

`javax.servlet.ServletException: No JasperPrint documents found on the HTTP session. at net.sf.jasperreports.j2ee.servlets.ImageServlet.se rvice(ImageServlet.java:106) at javax.servlet.http.HttpServlet.service(HttpServlet .java:810)`

Since thie image uri is giving an exception, you will see broken images in the HTML.  
So, it is mandatory to set the attribute ImageServlet.DEFAULT\_JASPER\_PRINT\_SESSION\_ATTRIBUTE to the JasperPrint object in the session.

*:* [jasper][]

转载于:https://my.oschina.net/liango/blog/88039

[80_]: https://my.oschina.net/u/2663968/blog/3051541
[hot3.png]: /images/20220115/8e6092e083404c9a835f110037ab3957.png
[Jasper Reports _ Web App _ HTML Reports]: http://deepaksrivastav.com/?p=79
[deepak]: http://deepaksrivastav.com/?author=1
[Jasper Reports]: http://deepaksrivastav.com/?cat=8
[jasper]: http://deepaksrivastav.com/?tag=jasper