How can one programmatically read the graph values from a Powerpoint presentation using Apache's POI?

I have a Powerpoint presentation with an graph which I want to access using Java and Apache's POI. When I edit the graph data using Powerpoint an Excel window opens with the values, I want to access these values from my Java application.

How does one access the values of the graph programmatically?

In the first part we need to navigate to an XSLFChart object:

final String filename = "resources/fptbenchmark/Powerpoint Import.pptx";
final XMLSlideShow ppt = new XMLSlideShow(new FileInputStream(filename));

final XSLFSlide slide = ppt.getSlides()[5];

The slide contains different parts (getRelations()) one of which should contain the XSLFChart:

final List<POIXMLDocumentPart> relations = slide.getRelations();
assert relations.size() == 3;

final XSLFChart xslfChart = (XSLFChart)relations.get(2);

When you examine the xslfChart variable in the debugger you will notice that the field CTChartImpl chart shows the underlying XML data, which might look like this:

<xml-fragment xmlns:c="http://schemas.openxmlformats.org/drawingml/2006/chart"
xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main"
xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
<c:autoTitleDeleted val="0"/>
<c:plotArea>
  <c:scatterChart>
    <c:ser>
      <c:tx>
        <c:strRef>
          <c:f>Sheet1!$E$8</c:f>
          <c:strCache>
            <c:ptCount val="1"/>
            <c:pt idx="0">
              <c:v>y axis caption</c:v>
            </c:pt>
          </c:strCache>
        </c:strRef>
      </c:tx>
      <c:xVal>
        <c:numRef>
          <c:f>Sheet1!$A$9:$A$28</c:f>
          <c:numCache>
            <c:formatCode>General</c:formatCode>
            <c:ptCount val="20"/>
            <c:pt idx="0">
              <c:v>1200</c:v>
            </c:pt>
            <c:pt idx="1">
              <c:v>1600</c:v>
            </c:pt>
            <c:pt idx="2">
              <c:v>2000</c:v>
            </c:pt>
...

You can naviage this tree starting with the CTChart:

CTChart ctChart = xslfChart.getCTChart();

Since there is a <c:plotArea> tag, you call the associated member function to access it:

CTPlotArea plotArea = ctChart.getPlotArea();

From there you should be able to navigate your way around

List<CTNumVal> ptList = plotArea.getScatterChartList().get(1)
    .getSerList().get(0)
    .getXVal()
    .getNumRef()
    .getNumCache()
    .getPtList();

Now you have access to the values:

ptList.get(0).getV();

References

来源：https://stackoverflow.com/questions/20324586/how-can-one-programmatically-read-the-graph-values-from-a-powerpoint-presentatio

标签

java

apache-poi

powerpoint