Java在word指定页数开头插入一张图片

可以使用Apache POI库来实现在Word指定页数开头插入一张图片。具体的实现方法可以参考以下代码：

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

import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.apache.poi.xwpf.usermodel.XWPFRun;
import org.apache.poi.xwpf.usermodel.XWPFPicture;
import org.apache.poi.xwpf.usermodel.XWPFPictureData;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.apache.poi.xwpf.usermodel.XWPFRun;
import org.apache.poi.xwpf.usermodel.XWPFPictureData;
import org.apache.poi.xwpf.usermodel.XWPFPicture;
import org.apache.poi.xwpf.usermodel.ParagraphAlignment;
import org.apache.poi.xwpf.usermodel.TextOrientation;
import org.apache.xmlbeans.XmlCursor;
import org.apache.xmlbeans.XmlException;
import org.apache.xmlbeans.XmlObject;
import org.apache.xmlbeans.impl.xb.xmlschema.SpaceAttribute$Enum;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTRelativePosition;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTWrapText;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTP;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTPoint2D;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTAnchor;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTBlip;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.STWrapText;
import org.openxmlformats.schemas.drawingml.x2006.main.*;


public class WordImageInsertDemo {
    public static void main(String[] args) {
        try {
            String docxPath = "D:\\temp\\test.docx";
            int pageNumber = 2;
            String picPath = "D:\\temp\\test.png";

            //打开docx文件
            FileInputStream fis = new FileInputStream(docxPath);
            XWPFDocument document = new XWPFDocument(fis);
            fis.close();

            //获取目标页面的段落
            XWPFParagraph paragraph = document.getParagraphs().stream()
                    .filter(p -> document.getPosOfParagraph(p) >= document.getDocument().getBody().getSectPr().getPgSz().getH().intValue()*pageNumber)
                    .findFirst()
                    .orElse(null);

            if(paragraph == null) {
                System.out.println("未找到指定页面。");
                return;
            }

            //在目标段落前面插入一张图片
            XmlCursor cursor = paragraph.getCTP().newCursor();
            cursor.toPrevSibling();
            XWPFParagraph newParagraph = document.insertNewParagraph(cursor);
            XWPFRun newRun = newParagraph.createRun();
            newRun.addCarriageReturn();
            //图片嵌入段落
            String id = document.addPictureData(new FileInputStream(picPath), XWPFDocument.PICTURE_TYPE_PNG);
            XWPFPicture picture = newRun.addPicture(new FileInputStream(picPath), XWPFDocument.PICTURE_TYPE_PNG, "abcdef", Units.toEMU(180), Units.toEMU(100));

            //设置图片位置（水平和垂直居中）
            picture.getCTPicture().getSpPr().getLn().setNoFill(true); //去掉边框
            CTPicture ctPic = picture.getCTPicture();

            CTTransform2D ctTransform2D = CTTransform2D.Factory.newInstance();
            ctTransform2D.setRot(0);
            CTPoint2D ctPoint2D = ctTransform2D.addNewOff();
            ctPoint2D.setX(Units.toEMU(400)); //横坐标
            ctPoint2D.setY(Units.toEMU(200)); //纵坐标
            ctPic.getSpPr().getXfrm().setOff(ctTransform2D);

            CTAnchor ctAnchor = ctPic.getAnchor();
            ctAnchor.setSimplePos2(false);
            ctAnchor.setX(0);
            ctAnchor.setY(0);
            CTMarker ctMarker = ctAnchor.addNewFrom();
            ctMarker.setCol(0);
            ctMarker.setColOff(0);
            ctMarker.setRow(0);
            ctMarker.setRowOff(0);
            ctMarker = ctAnchor.addNewTo();
            ctMarker.setCol(0);
            ctMarker.setColOff(0);
            ctMarker.setRow(0);
            ctMarker.setRowOff(0);

            //保存docx文件
            FileOutputStream fos = new FileOutputStream(docxPath);
            document.write(fos);
            fos.close();
            System.out.println("图片插入成功！");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在这段代码中，首先打开docx文件，并根据指定的页数获取目标段落。然后，在目标段落前插入一张图片，并设置该图片的位置为垂直和水平居中。最后保存docx文件即可。