我正在使用 iReport 设计一个 jasper 报告，它接受一个参数并从给定的 URL 获取图像:

参数是用户在推特上的用户名，url是用户头像。

当图像存在时它工作得很好。如果不是，则抛出以下异常:

    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...

我该如何处理 jrxml 文件中的这种情况？

我想简单地添加一个固定的 URL 地址，以防它找不到。

有人有什么建议吗？

Cảm ơn!

1 Câu trả lời

我认为您需要添加一个额外的辅助类来处理这个问题。您需要一个静态方法 boolean urlExists(String url)这将允许您将其放入 imageExpression 中:

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

编写一个简单的类……但显然，添加另一个 .jar 文件会增加复杂性。如果没有这种方法，我就看不到在 .jrxml 中进行处理的任何方法。

关于url - 碧 Jade : error opening input stream from url，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8340874/