poi 移除图片_poi 获取excel中图片(转载)

先贴代码,再解释与疑问(这段代码是我努力了半天的结果)

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFClientAnchor;

import org.apache.poi.hssf.usermodel.HSSFPicture;

import org.apache.poi.hssf.usermodel.HSSFPictureData;

import org.apache.poi.hssf.usermodel.HSSFShape;

import org.apache.poi.hssf.usermodel.HSSFSheet;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import org.apache.poi.openxml4j.exceptions.InvalidFormatException;

import org.apache.poi.ss.usermodel.PictureData;

import org.apache.poi.ss.usermodel.WorkbookFactory;

public class ReadPicturesFromExcel {

public static void main(String[] args) throws InvalidFormatException,

Exception {

InputStream inp = new FileInputStream(

"D:\\Users\\Fancy1_Fan\\桌面\\work\\test.xls");

HSSFWorkbook workbook = (HSSFWorkbook) WorkbookFactory.create(inp);

List pictures = workbook.getAllPictures();

HSSFSheet sheet = (HSSFSheet) workbook.getSheetAt(0);

int i = 0;

for (HSSFShape shape : sheet.getDrawingPatriarch().getChildren()) {

HSSFClientAnchor anchor = (HSSFClientAnchor) shape.getAnchor();

if (shape instanceof HSSFPicture) {

HSSFPicture pic = (HSSFPicture) shape;

int row = anchor.getRow1();

System.out.println(i + "--->" + anchor.getRow1() + ":"

+ anchor.getCol1());

int pictureIndex = pic.getPictureIndex()-1;

HSSFPictureData picData = pictures.get(pictureIndex);

System.out.println(i + "--->" + pictureIndex);

savePic(row, picData);

}

i++;

}

}

private static void savePic(int i, PictureData pic) throws Exception {

String ext = pic.suggestFileExtension();

byte[] data = pic.getData();

if (ext.equals("jpeg")) {

FileOutputStream out = new FileOutputStream(

"D:\\Users\\Fancy1_Fan\\桌面\\work\\pict" + i + ".jpg");

out.write(data);

out.close();

}

if (ext.equals("png")) {

FileOutputStream out = new FileOutputStream(

"D:\\Users\\Fancy1_Fan\\桌面\\work\\pict" + i + ".png");

out.write(data);

out.close();

}

}

}

思路:

1.获得所有图片---->

2.得到sheet DrawingPatriarch的所有shape--->

3.获得shape的anchor --->

4.获得picture的pictureIndex(这个很关键)------->

5.最后假定pictureIndex就是allPictures中图片的位置,从而获得这张picture的data信息.

问题:

对于最后的假定没有官方文档的支持,所以有待测试.但是简单测试结果是ok的!

对于假定的证明:

官方文档向excel添加图片的流程是:

1.调用workbook的addPicture,并且返回此pictureIndex------>

2.然后创建一个ClientAnchor--------->

3.最后通过这个pictureIndex和Anchor把它绘到sheet上

由此可见pictureIndex,ClientAnchor以及pictureData是一一对应的关系,只要能够关联这三者,就可以获得

Excel中picture的完整信息了.

然而根据poi的api,只能单独获得picture,或者包含pictureIndex和anchor的HSSFPicture,并没有把它们关联在一起.

查看源码发现 HSSFWorkbook只不过是一个外观类,或者适配器类,low level工作类为InternalWorkbook

Java代码  

/**

* this is the reference to the low level Workbook object

*/

private InternalWorkbook workbook;

查看InternalWorkbook有api如下

Java代码  

public EscherBSERecord getBSERecord(int pictureIndex) {

return escherBSERecords.get(pictureIndex-1);

}

此处表明:如果能获得InternalWorkbook对象和pictureIndex,就可以获得图片数据和信息.但是没法通过 HSSFWorkbook对象获得InternalWorkbook对象,因为如下:(此方法为包访问)

Java代码  

InternalWorkbook getWorkbook() {

return workbook;

}

但是观察InternalWorkbook可以发现,如图:

Java代码  

private List escherBSERecords;

保存图像数据的底层是一个List有序的集合.以及根据getBSERecord方法,就推断出picutreIndex就是表示picture在List里面的下标.

以上仅仅是个人的见解,由于对于poi的整体设计理念并没有把握,所以对于以上问题暂时找不到没有一个合理的解释.