Error message here!

Hide Error message here!

忘记密码?

Error message here!

请输入正确邮箱

Hide Error message here!

密码丢失?请输入您的电子邮件地址。您将收到一个重设密码链接。

Error message here!

返回登录

Close

java 库将 pdf 文件转换成高清图片方法

crazyCodeLove 2019-08-19 15:33:00 阅读数:45 评论数:0 点赞数:0 收藏数:0

近期需要将 pdf 文件转成高清图片,使用库是 pdfbox、fontbox。可以使用 renderImageWithDPI 方法指定转换的清晰度,当然清晰度越高,转换需要的时间越长,转换出来的图片越大,越清晰。

说明:由于 adobo 软件越来越强大,支持的格式越来越多,这造成了 java 软件有些不能转换。所以对于新的格式可能会有转换问题。

1 引入依赖

<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>pdfbox</artifactId>
<version>2.0.</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.pdfbox/fontbox -->
<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>fontbox</artifactId>
<version>2.0.</version>
</dependency>

 

2 代码如下

public static void convertPdf2Image(String pdfPath, String imageDirPath) {
log.info("start convert pdf file:[{}] to image path:[{}]", pdfPath, imageDirPath);
if (!new File(pdfPath).exists()) {
log.info("pdfFilename:[{}] not exist", pdfPath);
return;
}
if (!new File(imageDirPath).exists()) {
log.info("imageDir:[{}] not exist", imageDirPath);
return;
}
byte[] pdfContent = FileUtil.getFileContentByte(pdfPath);
String filename = FileUtil.getFilename(pdfPath);
float dpi = ;
convertPdf2Image(pdfContent, filename, imageDirPath, dpi);
log.info("convert pdf file:[{}] to image success", filename);
}
private static void convertPdf2Image(byte[] pdfContent, String pdfFilename, String imageDirPath, float dpi) {
log.info("convert pdfFilename:[{}] to imageDir:[{}] with dpi:[{}]", pdfFilename, imageDirPath, dpi);
if (ArrayUtils.isEmpty(pdfContent)) {
return;
}
// 为了保证显示清除,至少 90
if (dpi < ) {
dpi = ;
}
String baseSir = imageDirPath;
if (baseSir.endsWith("/") || baseSir.endsWith("\\")) {
baseSir += pdfFilename + "_";
} else {
baseSir += File.separator + pdfFilename + "_";
}
PDDocument document = null;
BufferedOutputStream outputStream = null;
try {
document = PDDocument.load(pdfContent);
int pageCount = document.getNumberOfPages();
PDFRenderer pdfRenderer = new PDFRenderer(document);
String imgPath;
for (int i = ; i < pageCount; i++) {
imgPath = baseSir + i + ".png";
outputStream = new BufferedOutputStream(new FileOutputStream(imgPath));
BufferedImage image = pdfRenderer.renderImageWithDPI(i, dpi, ImageType.RGB);
ImageIO.write(image, "png", outputStream);
outputStream.close();
log.info("convert to png, total[{}], now[{}], ori:[{}], des[{}]", pageCount, i + , pdfFilename, imgPath);
}
} catch (IOException e) {
log.error("convert pdf to image error, pdfFilename:" + pdfFilename, e);
} finally {
IOUtil.closeSilently(outputStream);
IOUtil.closeSilently(document);
}
}
// IOUtil.closeSilently 代码
public static void closeSilently(Closeable io) {
if (io != null) {
try {
io.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

在实际使用中遇到问题

1)ERROR o.a.p.contentstream.PDFStreamEngine 911 - Cannot read JBIG2 image: jbig2-imageio is not installed

2)Cannot read JPEG2000 image: Java Advanced Imaging (JAI) Image I/O Tools are not installed

以上两个问题需要使用 JAI 插件和 jbig2 插件支持,通过引入 jai-imageio-core、jai-imageio-jpeg2000、jbig2-imageio

<dependency>
<groupId>com.github.jai-imageio</groupId>
<artifactId>jai-imageio-core</artifactId>
<version>1.4.</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.jai-imageio/jai-imageio-jpeg2000 -->
<dependency>
<groupId>com.github.jai-imageio</groupId>
<artifactId>jai-imageio-jpeg2000</artifactId>
<version>1.3.</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.pdfbox/jbig2-imageio -->
<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>jbig2-imageio</artifactId>
<version>3.0.</version>
</dependency>

参考问题文件

https://github.com/crazyCodeLove/studentservice/blob/master/sys/src/main/resources/pdffile/000208-p1.pdf

https://github.com/crazyCodeLove/studentservice/blob/master/sys/src/main/resources/pdffile/001659-p14.pdf

https://github.com/crazyCodeLove/studentservice/blob/master/sys/src/main/resources/pdffile/main%20doc.pdf

 

 

参考文献

https://stackoverflow.com/questions/42169154/pdfbox1-8-12-convert-pdf-to-white-page-image

https://stackoverflow.com/questions/20424796/pdf-box-generating-blank-images-due-to-jbig2-images-in-it

https://blog.csdn.net/qq_15801963/article/details/80746830

https://my.oschina.net/u/2345654/blog/1058192

 

版权声明
本文为[crazyCodeLove]所创,转载请带上原文链接,感谢
https://www.cnblogs.com/zhaopengcheng/p/11377458.html