使用Apache POI从PowerPoint幻灯片中删除图表

Question

我们正在尝试使用Apache POI 3.16从PowerPoint幻灯片中删除图表，但我们遇到了困难。

我们的代码执行以下步骤：

1. 打开现有的 PowerPoint 文档（模板文档）
2. 添加和删除幻灯片
3. 更新现有幻灯片中的图表

这很好。

在某些时候，我们需要从给定的幻灯片中删除图表。这是我们的尝试：

OPCPackage pkg = ppt.getPackage();

String chartRelationId = slide.getRelationId(chart);
pkg.removeRelationship(chartRelationId);

pkg.removePart(chart.getPackagePart());

< code>pkg.removePart()调用似乎可以工作，但是将最终的PowerPoint文档写入磁盘失败，并出现一个异常，指出无法删除部件文件(可能是因为我们已经删除了它)。

＜code＞包。removeRelationship（）调用也会在将文档写入磁盘时触发一个异常，该异常表明核心。xml已存在。

是否可以使用Apache POI从PowerPoint幻灯片中删除图表？如果是，如何？

Answer 1

由于＜code＞XSLFChart＜/code＞处于@Beta状态，因此直到现在还没有明确的＜code＞Shape＜/code>图表。因此，使用＜code＞apache poi＜/code＞，我们只能得到包含图表的＜code＞XSLFGraphicFrame＜/code＞。但从幻灯片中删除＜code＞XSLFGraphicFrame＜/code＞并不会同时删除所有相关的图表部分。因此，自上而下移除相关图表部分意味着直到现在才实现从＜code＞POIXLDocumentPart＜/code＞级别向下到＜code＞PackagePart＜/code＞级别。由于＜code＞POIXLDocumentPart＜/code＞中的所有相关方法都受到保护，并且＜code＞XSLFChart＜/code＞本身是最终的，因此不太容易解决。

下面的代码显示了问题。评论如下。

该代码从第一张幻灯片中删除所有图表，并删除所有关系和相关部分，这些部分将是：/ppt/嵌入/Microsoft_Excel_WorksheetN.xlsx，/ppt/图表/颜色N.xml和/ppt/图表/样式N.xml。只有 /ppt/图表/图表N.xml不能被删除，因为它是注释。

import java.io.FileInputStream;
import java.io.FileOutputStream;

import org.apache.poi.xslf.usermodel.*;
import org.apache.poi.sl.usermodel.*;

import org.apache.poi.POIXMLDocumentPart;

import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackagePart;
import org.apache.poi.openxml4j.opc.PackageRelationshipCollection;
import org.apache.poi.openxml4j.opc.PackageRelationship;

import org.apache.xmlbeans.XmlObject;

import java.util.Map;
import java.util.HashMap;

import java.util.regex.Pattern;

public class ReadPPTRemoveChart {

 public static void main(String[] args) throws Exception {

  XMLSlideShow slideShow = new XMLSlideShow(new FileInputStream("PPTWithCharts.pptx"));

  XSLFSlide slide = slideShow.getSlides().get(0);

  Map<String, XSLFGraphicFrame> chartFramesToRemove = new HashMap<>();

  for (XSLFShape shape : slide.getShapes()) {
   if (shape instanceof XSLFGraphicFrame) {
    XSLFGraphicFrame graphicframe = (XSLFGraphicFrame)shape;
    XmlObject xmlobject = graphicframe.getXmlObject();
    XmlObject[] graphics = xmlobject.selectPath(
                            "declare namespace a='http://schemas.openxmlformats.org/drawingml/2006/main' " +
                            ".//a:graphic");
    if (graphics.length > 0) { //we have a XSLFGraphicFrame containing a:graphic
     XmlObject graphic = graphics[0];
     XmlObject[] charts = graphic.selectPath(
                           "declare namespace c='http://schemas.openxmlformats.org/drawingml/2006/chart' " +
                           ".//c:chart");
     if (charts.length > 0) { //we have a XSLFGraphicFrame containing c:chart
      XmlObject chart = charts[0];
      String rid = chart.selectAttribute(
                          "http://schemas.openxmlformats.org/officeDocument/2006/relationships", "id")
                          .newCursor().getTextValue();
      chartFramesToRemove.put(rid, graphicframe);
     }
    }
   }
  }

  PackagePart slidepart = slide.getPackagePart();
  OPCPackage opcpackage = slideShow.getPackage();

  for (String rid : chartFramesToRemove.keySet()) {
   //at frist remove the XSLFGraphicFrame
   XSLFGraphicFrame chartFrame = chartFramesToRemove.get(rid);
   slide.removeShape(chartFrame);
   //Here is the problem in my opinion. This **should** remove all related parts too.
   //But since XSLFChart is @Beta, it does not.

   //So we try doing removing the related parts manually.
   //we get the PackagePart of the chart
   PackageRelationship relship = slidepart.getRelationships().getRelationshipByID(rid);
   PackagePart chartpart = slidepart.getRelatedPart(relship);

   //now we get and remove all the relations and related PackageParts from this chartpart
   //this are /ppt/embeddings/Microsoft_Excel_WorksheetN.xlsx, /ppt/charts/colorsN.xml 
   //and /ppt/charts/styleN.xml
   for (PackageRelationship chartrelship : chartpart.getRelationships()) {
    String partname = chartrelship.getTargetURI().toString();
    PackagePart part = opcpackage.getPartsByName(Pattern.compile(partname)).get(0);
    opcpackage.removePart(part);
    chartpart.removeRelationship(chartrelship.getId());
   }
   //this works

   //now we **should** be able removing the relationship to the chartpart from the slide too
   //but this seems not to be possible
   //doing this on PackagePart level works:
   slidepart.removeRelationship(rid);
   for (PackageRelationship sliderelship : slidepart.getRelationships()) {
    System.out.println("rel PP level: " + sliderelship.getTargetURI().toString());
   }
   //all relationships to /ppt/charts/chartN.xml are removed

   //but on POIXMLDocumentPart level this has no effect
   for (POIXMLDocumentPart sliderelpart : slide.getRelations()) {
    System.out.println("rel POIXML level: " + sliderelpart.getPackagePart().getPartName());
   }
   //relationships to /ppt/charts/chartN.xml are **not** removed

   //So we cannot remove the chartpart.
   //If we would do this, then while slideShow.write the 
   //org.apache.poi.xslf.usermodel.XSLFChart.commit in XSLFChart.java fails 
   //because after removing the PackagePart is absent but the relation is still there.
   //opcpackage.removePart(chartpart);

  }


  slideShow.write(new FileOutputStream("PPTWithChartsNew.pptx"));
  slideShow.close();
 }
}

使用< code>PowerPoint打开< code > pptwithchartsnew . pptx 并保存后，不必要的< code >/PPT/charts/stylen . XML 部分也被删除，因为它们之间不再有关系。

2017年9月24日编辑：

找到了使用反射的解决方案。如上所述，删除相关的图表部分需要自上而下，这意味着从POIXLDocumentPart级别向下到PackagePart级别。自从＜code＞POIXLDocumentPart以来。removeRelation＜/code＞是受保护的，我们需要使用反射来实现这一点。

import java.io.FileInputStream;
import java.io.FileOutputStream;

import org.apache.poi.xslf.usermodel.*;
import org.apache.poi.sl.usermodel.*;

import org.apache.poi.POIXMLDocumentPart;

import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackagePart;
import org.apache.poi.openxml4j.opc.PackageRelationshipCollection;
import org.apache.poi.openxml4j.opc.PackageRelationship;

import org.apache.xmlbeans.XmlObject;

import java.util.Map;
import java.util.HashMap;

import java.util.regex.Pattern;

import java.lang.reflect.Method;

public class ReadPPTRemoveChart {

 public static void main(String[] args) throws Exception {

  XMLSlideShow slideShow = new XMLSlideShow(new FileInputStream("PPTWithCharts.pptx"));

  XSLFSlide slide = slideShow.getSlides().get(0);

  Map<String, XSLFGraphicFrame> chartFramesToRemove = new HashMap<>();

  for (XSLFShape shape : slide.getShapes()) {
   if (shape instanceof XSLFGraphicFrame) {
    XSLFGraphicFrame graphicframe = (XSLFGraphicFrame)shape;
    XmlObject xmlobject = graphicframe.getXmlObject();
    XmlObject[] graphics = xmlobject.selectPath(
                            "declare namespace a='http://schemas.openxmlformats.org/drawingml/2006/main' " +
                            ".//a:graphic");
    if (graphics.length > 0) { //we have a XSLFGraphicFrame containing a:graphic
     XmlObject graphic = graphics[0];
     XmlObject[] charts = graphic.selectPath(
                           "declare namespace c='http://schemas.openxmlformats.org/drawingml/2006/chart' " +
                           ".//c:chart");
     if (charts.length > 0) { //we have a XSLFGraphicFrame containing c:chart
      XmlObject chart = charts[0];
      String rid = chart.selectAttribute(
                          "http://schemas.openxmlformats.org/officeDocument/2006/relationships", "id")
                          .newCursor().getTextValue();
      chartFramesToRemove.put(rid, graphicframe);
     }
    }
   }
  }

  PackagePart slidepart = slide.getPackagePart();
  OPCPackage opcpackage = slideShow.getPackage();

  for (String rid : chartFramesToRemove.keySet()) {
   //at frist remove the XSLFGraphicFrame
   XSLFGraphicFrame chartFrame = chartFramesToRemove.get(rid);
   slide.removeShape(chartFrame);
   //Here is the problem in my opinion. This **should** remove all related parts too.
   //But since XSLFChart is @Beta, it does not.

   //So we try doing removing the related parts manually.

   //we get the PackagePart of the chart
   PackageRelationship relship = slidepart.getRelationships().getRelationshipByID(rid);
   PackagePart chartpart = slidepart.getRelatedPart(relship);

   //now we get and remove all the relations and related PackageParts from this chartpart
   //this are /ppt/embeddings/Microsoft_Excel_WorksheetN.xlsx, /ppt/charts/colorsN.xml 
   //and /ppt/charts/styleN.xml
   for (PackageRelationship chartrelship : chartpart.getRelationships()) {
    String partname = chartrelship.getTargetURI().toString();
    PackagePart part = opcpackage.getPartsByName(Pattern.compile(partname)).get(0);
    opcpackage.removePart(part);
    chartpart.removeRelationship(chartrelship.getId());
   }

   //now we remove the chart part from the slide part
   //We need doing this on POIXMLDocumentPart level. 
   //Since POIXMLDocumentPart.removeRelation is protected, we need doing this using reflection
   XSLFChart chart = (XSLFChart)slide.getRelationById(rid);
   Method removeRelation = POIXMLDocumentPart.class.getDeclaredMethod("removeRelation", POIXMLDocumentPart.class); 
   removeRelation.setAccessible(true); 
   removeRelation.invoke(slide, chart);

  }

  slideShow.write(new FileOutputStream("PPTWithChartsNew.pptx"));
  slideShow.close();
 }
}