Jasper:打开来自URL的输入流时出错 [英] Jasper: error opening input stream from url

问题描述

我正在使用iReport设计一个碧玉报告，该报告采用一个参数并从给定的URL提取图像:

I'm designing a jasper report using iReport which takes a parameter and fetches an image from a given URL:

该参数是用户在Twitter中的屏幕名称，而url是其个人资料图片.

The parameter is a user's screen name in twitter, and the url is it's profile image.

    <image>
       <reportElement x="4" y="51" width="73" height="64"/>
           <imageExpression><![CDATA["https://api.twitter.com/1/users/profile_image?screen_name="+$F{user_screen_name}+"&size=bigger"]]></imageExpression>
    </image>

当图像存在时，效果很好.如果不是，则会引发以下异常:

It works great when the image exists. If it doesn't the following exception is thrown:

    Error filling print... net.sf.jasperreports.engine.JRException: Error opening input stream from URL :
    https://api.twitter.com/1/users/profile_image?screen_name=CPTCurtisHervey&size=bigger 
    Setting up the file resolver... net.sf.jasperreports.engine.JRRuntimeException:
    net.sf.jasperreports.engine.JRException: Error opening input stream from URL :
    https://api.twitter.com/1/users/profile_image?screen_name=CPTCurtisHervey&size=bigger 
    at net.sf.jasperreports.repo.DefaultRepositoryService.getInputStream(DefaultRepositoryService.java:138)
    at net.sf.jasperreports.repo.RepositoryUtil.findInputStream(RepositoryUtil.java:186)     
    at net.sf.jasperreports.repo.RepositoryUtil.getBytes(RepositoryUtil.java:202)
    at net.sf.jasperreports.engine.JRImageRenderer.getInstance(JRImageRenderer.java:141)     
    at net.sf.jasperreports.engine.fill.JRFillImage.evaluateImage(JRFillImage.java:498)
    at net.sf.jasperreports.engine.fill.JRFillImage.evaluate(JRFillImage.java:441)
    at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:257)
    at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:468)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:2037)     
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:761)     
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportContent(JRVerticalFiller.java:291)
    at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:133)     
    at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:903)
    at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:813)
    at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:58)
    at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:417)
    at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:247)
    at com.jaspersoft.ireport.designer.compiler.IReportCompiler.run(IReportCompiler.java:878)
    at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)
    at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997) Caused by: 
    net.sf.jasperreports.engine.JRException: Error opening input stream from URL : 
    https://api.twitter.com/1/users/profile_image?screen_name=CPTCurtisHervey&size=bigger     
    at net.sf.jasperreports.engine.util.JRLoader.getInputStream(JRLoader.java:314)
    at net.sf.jasperreports.repo.DefaultRepositoryService.getInputStream(DefaultRepositoryService.java:121)
    ... 19 more Caused by: java.io.FileNotFoundException: 
    https://api.twitter.com/1/users/profile_image?screen_name=CPTCurtisHervey&size=bigger     
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1401)     
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
    at java.net.URL.openStream(URL.java:1029)     
    at net.sf.jasperreports.engine.util.JRLoader.getInputStream(JRLoader.java:310)... 20 more 
    Print not filled. Try to use an EmptyDataSource...

如何处理jrxml文件中的这种情况?

How can i handle this situation in the jrxml file?

我想简单地添加一个固定的URL地址，以防找不到.

I would like to simply add a fixed URL address in case it can't find one.

有人有什么建议吗?

谢谢！

推荐答案

我认为您需要添加一个额外的帮助程序类来处理此问题.您需要一个静态方法boolean urlExists(String url)，该方法可以将其放入imageExpression:

I think you need to add an additional helper class to handle this. You need a static method boolean urlExists(String url) that would allow you to put this in the imageExpression:

MyClass.urlExists($F{image_url}) ? $F{image_url} : $P{fallback_image}

这将是一个简单的类编写...但是显然，添加另一个.jar文件存在额外的复杂性.如果没有该方法，则无法在.jrxml中看到任何处理方式.

It would be a simple class to write... but clearly there's additional complexity in adding in another .jar file. Without that method, I can't see any way to do the processing in the .jrxml.

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