JasperReport image inside report jrxml on HTML src is missing?

Question

I have a method in Java using the JasperReport to export a report in HTML like this:

public static byte[] exportToHtmlWithConn(String urlReport, Connection conn) throws JRException {

    Map<String, Object> parameters = new HashMap<>();

    String urlLogo = "/reports/image.PNG";

    String urlLogo2 = JasperUtilities.class.getResource(urlLogo).toString();

    parameters.put("CONTEXT", urlLogo2);

    JasperReport report = JasperCompileManager.compileReport(JasperUtilities.class.getResourceAsStream(urlReport));
    jasperPrint = JasperFillManager.fillReport(report, parameters, conn);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    HtmlExporter exporter = new HtmlExporter();
    exporter.setExporterInput(new SimpleExporterInput(jasperPrint));
    exporter.setExporterOutput(new SimpleHtmlExporterOutput(baos));
    exporter.exportReport();

    return baos.toByteArray();
}

In the report I have one parameter like this:

<parameter name="CONTEXT" class="java.lang.String">
    <parameterDescription><![CDATA[CONTEXT]]></parameterDescription>
    <defaultValueExpression><![CDATA[0]]></defaultValueExpression>
</parameter>

And the idea is to show one image inside the report

<image>
    <reportElement x="180" y="-5" width="185" height="80" uuid="d8978cb8-9c4e-4d1b-83fb-a83356803128">
    <property name="com.jaspersoft.studio.unit.width" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.height" value="pixel"/>
    </reportElement>
    <imageExpression><![CDATA[$P{CONTEXT}.toString()]]></imageExpression>
</image>

The problem is when I use this method to export a HTML the image is missing but when I use the same structure for example to export a PDF or xlsx the image works Ok.

Why not work in HTML? When I check the code in html the src is empty

<img src="" style="width: 185px" alt=""/>

Can someone help with any idea about this? I have seen many ways to do the same but this has been impossible to work. I also have used one parameters like java.io.InputStream and the image works in PDF and others formats. But in HTML doesn't work.

Also I have used others images but the same problem.

Answer 1

this is my solution:

I need to export in PDF, xlsx and show the report in HTML. For each there are a method. But I had the problem with HTML the image missing. But the solution thanks to Narcis is like this:

public static byte[] exportToHtmlWithConn(String urlReport, Connection conn) throws JRException {

    Map<String, Object> parameters = new HashMap<>();

    parameters = returnLogoPutAsParam();

    JasperReport report = JasperCompileManager.compileReport(JasperUtilities.class.getResourceAsStream(urlReport));
    jasperPrint = JasperFillManager.fillReport(report, parameters, conn);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    HtmlExporter exporter = new HtmlExporter();
    exporter.setExporterInput(new SimpleExporterInput(jasperPrint));

    SimpleHtmlExporterOutput htmlExporterOutput = new SimpleHtmlExporterOutput(baos);
    htmlExporterOutput.setImageHandler(new FileHtmlResourceHandler(new File("html_images"), "/web/resources/images/logo.png"));

    exporter.setExporterOutput(htmlExporterOutput);
    exporter.exportReport();

    return baos.toByteArray();
}

In this part htmlExporterOutput.setImageHandler(new FileHtmlResourceHandler(new File("html_images"), "/web/resources/images/logo.png")); I put the logo.png in one folder inside the resources in my frontend.

I use the method returnLogoPutAsParam(); for return the image for PDF and xlsx

public static Map<String, Object> returnLogoPutAsParam() {
    Map<String, Object> parameters = new HashMap<>();
    InputStream logo = returnLogoByte();
    parameters.put("logo", logo);
    return parameters;
}

And finally this:

public static InputStream returnLogoByte() {
    InputStream is = null;
    try {
        byte[] imageByteArray;
        BufferedImage img = ImageIO.read(JasperUtilities.class.getResourceAsStream("/reports/logo.png"));
        ByteArrayOutputStream bas = new ByteArrayOutputStream();
        ImageIO.write(img, "bmp", bas);
        imageByteArray = bas.toByteArray();
        System.out.println("Byte[] logo:" + imageByteArray.length);
        is = new ByteArrayInputStream(imageByteArray);
        return is;
    } catch (Exception e) {
        System.out.println("Error reading logo.");
        e.printStackTrace();
    }
    return is;
}

Really I am not sure if this is the best solution but it works for one image.

I hope this info help to someone.

Cheers.