用Apache-poi在excel中插入图像

Question

package com.shangzhu.drt;

import org.apache.poi.ss.usermodel.Picture;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.*;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;

/**
 * Created by lixiaoming on 2017/6/26.
 */
public class ImageTest2 {

    private static void insertImageWithPOI() throws Exception {
        XSSFWorkbook wwb = new XSSFWorkbook();
        XSSFSheet ws = wwb.createSheet("sheet0");

        BufferedImage image = ImageIO.read(new File("D:/poi.png"));
        ByteArrayOutputStream baps = new ByteArrayOutputStream();
        ImageIO.write(image,"png",baps);

        int pictureIdx = wwb.addPicture(baps.toByteArray(), Workbook.PICTURE_TYPE_PNG);

        XSSFDrawing drawing = ws.createDrawingPatriarch();
        XSSFCreationHelper helper = wwb.getCreationHelper();
        XSSFClientAnchor anchor = helper.createClientAnchor();
        anchor.setCol1(1);
        anchor.setRow1(1);

        Picture picture = drawing.createPicture(anchor, pictureIdx);
        picture.resize();

        File excelFile = new File("D:/POI.xlsx");
        OutputStream ops = new FileOutputStream(excelFile);
        wwb.write(ops);
    }

    public static void main(String[] args) {
        try {
            insertImageWithPOI();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

下面是代码：d：/poi.png中的图片（“d：/poi.png”）

我不认为处理图像的源代码有问题，但我不知道我错过了什么

Answer 1

我确认使用默认列大小时有问题。xssfpicture.resize需要以像素为单位计算列宽，以获得xssfclientanchorcol2和dx2。只要使用默认列大小，那么这个计算似乎是错误的。

解决办法是在使用xssfpicture.resize之前定义显式列大小。那么以像素为单位的列宽计算似乎是正确的。

在代码中：

...
        Picture picture = drawing.createPicture(anchor, pictureIdx);

        for (int c=0; c<20; c++) ws.setColumnWidth(c, 11*256);
        picture.resize();
...