如何捕获从Jasper报告图像Servlet引发的异常

Question

My web application use JASPERREPORTS to compile and serve various reports. All the images present in the report draws from the ImageServlet net.sf.jasperreports.j2ee.servlets.ImageServlet .

<servlet>
    <servlet-name>ImageServlet</servlet-name>
    <servlet-class>net.sf.jasperreports.j2ee.servlets.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>ImageServlet</servlet-name>
    <url-pattern>/image</url-pattern>
</servlet-mapping>

The request for the image is something like this:

GET /watapp/image?rand=0.5039537955900038&image=px

In the security audit of my application, it was raised that if the query parameters are altered like setting image=pxxx causes a 500 internal server error. So I need to handle this exception.

net.sf.jasperreports.engine.JRRuntimeException: Invalid image name: pxxx
        at net.sf.jasperreports.engine.export.JRHtmlExporter.getPrintElementIndex(JRHtmlExporter.java:2408)
        at net.sf.jasperreports.engine.export.JRHtmlExporter.getImage(JRHtmlExporter.java:695)
        at net.sf.jasperreports.j2ee.servlets.ImageServlet.service(ImageServlet.java:98)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.watapp.filters.login.ApplicationFilter.doFilter(ApplicationFilter.java:41)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:662)

My question is, how can handle this exception? The servlet comes along with the JASPER jar and I have no control over the code of the servlet. Please advice.

Answer 1

Create your own servlet and modify the servlet-mapping for /image to point to that instead of the jasper servlet.

Your new servlet does not have to do any of the work, it can simply pass on the request to the jasper servlet, but it gives you the ability to insert an exception handler to catch the JRRuntimeException .