Question

我正在尝试将图像作为二进制数据从我的数据库中提取并插入到 Jasper Reports 报告中。

使用 Jaspersoft Studio ，我在我的字段中读取并将其类型更改为java.awt.Image。然后，我将一个图像元素添加到我的报告中，并将表达式更改为$ {Attr1_icon} 当我尝试编译时，我得到：

net.sf.jasperreports.engine.JRException: net.sf.jasperreports.engine.JRException: Unable to get value for field 'Attr1_icon' of class 'java.awt.Image'
at com.jaspersoft.studio.editor.preview.view.control.ReportControler.fillReport(ReportControler.java:482)
at com.jaspersoft.studio.editor.preview.view.control.ReportControler.access$18(ReportControler.java:457)
at com.jaspersoft.studio.editor.preview.view.control.ReportControler$4.run(ReportControler.java:347)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
Caused by: net.sf.jasperreports.engine.JRException: Unable to get value for field 'Attr1_icon' of class 'java.awt.Image'
at net.sf.jasperreports.engine.JRResultSetDataSource.getFieldValue(JRResultSetDataSource.java:319)
at net.sf.jasperreports.engine.fill.JRFillDataset.setOldValues(JRFillDataset.java:1356)
at net.sf.jasperreports.engine.fill.JRFillDataset.next(JRFillDataset.java:1257)
at net.sf.jasperreports.engine.fill.JRFillDataset.next(JRFillDataset.java:1233)
at net.sf.jasperreports.engine.fill.JRBaseFiller.next(JRBaseFiller.java:1577)
at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:149)
at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:932)
at net.sf.jasperreports.engine.fill.BaseFillHandle$ReportFiller.run(BaseFillHandle.java:120)
at java.lang.Thread.run(Unknown Source)
Caused by: net.sf.jasperreports.engine.JRException: Image read failed.
at net.sf.jasperreports.engine.util.JRJdk14ImageReader.readImage(JRJdk14ImageReader.java:73)
at net.sf.jasperreports.engine.util.JRImageLoader.loadAwtImageFromBytes(JRImageLoader.java:167)
at net.sf.jasperreports.engine.JRResultSetDataSource.getFieldValue(JRResultSetDataSource.java:309)
Caused by: net.sf.jasperreports.engine.JRException: Image read failed.
at net.sf.jasperreports.engine.util.JRJdk14ImageReader.readImage(JRJdk14ImageReader.java:73)
at net.sf.jasperreports.engine.util.JRImageLoader.loadAwtImageFromBytes(JRImageLoader.java:167)
at net.sf.jasperreports.engine.JRResultSetDataSource.getFieldValue(JRResultSetDataSource.java:309)

导致此异常的源代码来自JRJdk14ImageReader.java：

public Image readImage(byte[] bytes) throws JRException {
    InputStream bais = new ByteArrayInputStream(bytes);

    Image image = null;
    try {
        image = ImageIO.read(bais);
    } catch (Exception e) {
        throw new JRException(e);
    } finally {
        try {
            bais.close();
        } catch (IOException e) {
        }
    }

    if (image == null) {
        throw new JRException("Image read failed."); // Line 73
    }

    return image;
}

因此，您可以看到图像为空。但我不明白为什么。我已经确认数据实际存在。如果我将数据类型更改为字符串并将其添加到普通文本字段，则会打印二进制数据。所以，我不认为它是null，因为传入的数据是null。

来自Javadoc：

Returns a BufferedImage as the result of decoding a supplied InputStream with an
ImageReader chosen automatically from among those currently registered. The InputStream
is wrapped in an ImageInputStream. If no registered ImageReader claims to be able to
read the resulting stream, null is returned.

所以我猜没有注册的ImageReader？我怎么能通过 Jaspersoft Studio 修复类似的东西？

编辑：我已经尝试使用java.io.InputStream作为建议here的类类型但是会导致相同的错误。的种类。一个很大的区别是，在 Jaspersoft Studio 中，如果出现错误，您可以将图像设置为显示为空白。如果我使用java.awt.Image，则此设置不执行任何操作。我仍然收到错误，报告没有建立。如果我使用java.io.InputStream，报表会生成，但图像为空。如果我打开错误报告，我会得到类似的堆栈跟踪，但它不完全相同：

net.sf.jasperreports.engine.JRRuntimeException: net.sf.jasperreports.engine.JRException: Image read failed.
at net.sf.jasperreports.engine.export.draw.PrintDrawVisitor.visit(PrintDrawVisitor.java:143)
at net.sf.jasperreports.engine.export.draw.PrintDrawVisitor.visit(PrintDrawVisitor.java:1)
at net.sf.jasperreports.engine.fill.JRTemplatePrintImage.accept(JRTemplatePrintImage.java:451)
at net.sf.jasperreports.engine.export.draw.FrameDrawer.draw(FrameDrawer.java:251)
at net.sf.jasperreports.engine.export.draw.FrameDrawer.draw(FrameDrawer.java:199)
at net.sf.jasperreports.engine.export.JRGraphics2DExporter.exportPage(JRGraphics2DExporter.java:273)
at net.sf.jasperreports.engine.export.JRGraphics2DExporter.exportReportToGraphics2D(JRGraphics2DExporter.java:246)
at net.sf.jasperreports.engine.export.JRGraphics2DExporter.exportReport(JRGraphics2DExporter.java:184)
at net.sf.jasperreports.eclipse.viewer.ViewerCanvas.renderPage(ViewerCanvas.java:369)
at net.sf.jasperreports.eclipse.viewer.ViewerCanvas.refresh(ViewerCanvas.java:344)
at net.sf.jasperreports.eclipse.viewer.ViewerCanvas$2.viewerStateChanged(ViewerCanvas.java:118)
at net.sf.jasperreports.eclipse.viewer.ReportViewer.fireViewerModelChanged(ReportViewer.java:383)
at net.sf.jasperreports.eclipse.viewer.ReportViewer.setPageIndex(ReportViewer.java:297)
at com.jaspersoft.studio.editor.preview.view.report.swt.SWTViewer.setJRPRint(SWTViewer.java:125)
at com.jaspersoft.studio.editor.preview.view.report.swt.SWTViewer.setJRPRint(SWTViewer.java:112)
at com.jaspersoft.studio.editor.preview.PreviewJRPrint.switchRightView(PreviewJRPrint.java:226)
at com.jaspersoft.studio.editor.preview.PreviewContainer.switchRightView(PreviewContainer.java:247)
at com.jaspersoft.studio.editor.preview.PreviewJRPrint$3.switchView(PreviewJRPrint.java:194)
at com.jaspersoft.studio.editor.preview.PreviewJRPrint$1.run(PreviewJRPrint.java:153)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4144)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at com.jaspersoft.studio.rcp.intro.Application.start(Application.java:97)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
Caused by: net.sf.jasperreports.engine.JRException: Image read failed.
at net.sf.jasperreports.engine.util.JRJdk14ImageReader.readImage(JRJdk14ImageReader.java:73)
at net.sf.jasperreports.engine.util.JRImageLoader.loadAwtImageFromBytes(JRImageLoader.java:167)
at net.sf.jasperreports.engine.JRImageRenderer.getImage(JRImageRenderer.java:407)
at net.sf.jasperreports.engine.JRImageRenderer.getDimension(JRImageRenderer.java:482)
at net.sf.jasperreports.engine.RenderableUtil.getOnErrorRendererForDimension(RenderableUtil.java:264)
at net.sf.jasperreports.engine.export.draw.ImageDrawer.draw(ImageDrawer.java:116)
at net.sf.jasperreports.engine.export.draw.PrintDrawVisitor.visit(PrintDrawVisitor.java:134)

但是，正如您所看到的，根本原因仍然来自JRJdk14ImageReader.java第73行。

其他一些可能有用的信息：

数据作为LONG BINARY（使用Sybase）存储在数据库中图像是base64编码的。

这个问题阻碍了我完成项目，截止日期快到了。任何帮助都会很棒。

编辑2：我将 Jaspersoft Studio 的版本从5.5更新到5.6，但没有做任何事情。

同样，对于表达式我试过javax.imageio.ImageIO.read（$ F {Attr1_icon}）这实际上不会产生任何错误，但图像是空白的。

Answer 1

即使我在问题中发布了它，我完全忽略了图像是Base64编码的事实，这意味着它是一个字符串。因此，Jasper无法使用此值，因此必须对其进行解码。这可以通过以下两种方式之一完成：

将表达式更改为：

new java.io.ByteArrayInputStream(javax.xml.DatatypeConverter.parseBase64Binary($F{ImageField}))

或简单地将数据库中的字符串转换为二进制。在Sybase中，这是base64_decode函数。转换后，您只需将类型更改为java.io.InputStream即可。

Answer 2

net.sf.jasperreports.engine.jreexception：图像读取失败。
我正在使用 jasperreports 6.1.0.
对于这个错误，我对图像属性进行了更改：

 lazy : checked,
 Using cache : false,
 on Error Type: Blank

从数据库显示图像。获取net.sf.jasperreports.engine.JRException：图像读取失败

2 个答案: