如何打开和替换java apache中的PDFBox流中的数据？
如何打开和替换java apache中的PDFBox流中的数据？
提问于 2015-09-16 19:43:22
我在我的java代码(Java1.6)中使用了apache 2.0.0版本。我正在努力弄清楚如何获得、替换并保存到我的pdf中
<stream> data here... <endstream> ?我的pdf文件如下：
596 0 obj
<<
/Filter /FlateDecode
/Length 3739
>>
stream
xњ[ЫnЬF}џoШ8эІАђhЮ/‰`@С%Hvќd-н“іXPJГ ...
endstream
endobj我找到了一个解决方案，我可以解码这条流。我使用了pdfbox 1.8.10.jar api中的"WriteDecodedDoc“命令。所以现在我有了文件的两个变体，但是我不知道如何处理这个流。此流包含页脚和页眉，其中放置了图像和文本。
我用PDFTextStripper类检查了我的文件。它可以从流中看到必要的数据，但是我不能使用这个类来替换数据并将数据保存回pdf文件。
我试着替换这个文本，只是打开一个文件作为文本，搜索文本，只在流中替换它并保存。但我对“无法提取嵌入式字体.”有一个问题。主要原因是我丢失了编码。我试着改变这个编码，但对我没有帮助。
顺便说一下，我不能使用iText。我应该在这里用免费的唇语。
谢谢你的解决方案。
编辑：
解码后，我的流就像
stream
/CS0 CS 0.412 0.416 0.423 SCN
0.25 w
/GS0 gs
q 1 0 0 1 72 78.425 cm
0 0 m
468 0 l
S
Q
/Span <</Lang (en-US)/MCID 83 >>BDC
BT
/T1_1 1 Tf
8 0 0 8 237.0609 64.8 Tm
[(www)11(.li)-14.9(nkto)-10(thesi)-8(tesho)-7.9(ouldbehere)15.1(.com)]TJ
/Span<</ActualText<FEFF0009>>> BDC
( )Tj
endstream我需要更换一个链接到一个不同的链接内流。这个：
[(www)11(.li)-14.9(nkto)-10(thesi)-8(tesho)-7.9(ouldbehere)15.1(.com)]TJ编辑2代码
public static void replaceLinksInPdf(String filePath) {
PDDocument document = null;
try {
document = PDDocument.load(new File(filePath));
if (document.isEncrypted()) {
document.setAllSecurityToBeRemoved(true);
System.out.println(filePath + " Doc was decrypted");
}
// COSBase cosb = document.getDocument().getObjects().get(27);
// e.g. this object contains <stream> bytecode <endstream> in the PDF file.
// it looks that
// document -> getDocument() -> objectPool #27 -> baseObject -> randomAccess -> bufferList size 10 has a data that I can't open and work
// document -> getDocument() -> objectPool #27 -> baseObject -> items -> all PDF's tag but NO a stream section
int pageNum = 0;
for (PDPage page : document.getPages()) {
PDFStreamParser parser = new PDFStreamParser(page);
parser.parse();
List<Object> tokens = parser.getTokens();
List<Object> newTokens = new ArrayList<Object>();
for (Object token : tokens) {
if (token instanceof Operator) {
COSDictionary dictionary = ((Operator) token).getImageParameters();
if (dictionary != null) {
System.out.println(dictionary.toString());
}
}
if (token instanceof Operator) {
Operator op = (Operator) token;
if (op.getName().equals("Tj")) {
// Tj contains 1 COSString
COSString previous = (COSString) newTokens.get(newTokens.size() - 1);
String string = previous.getString();
// check if string contains a necessary link
if (string.equals("www.linkhouldbehere.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test2.test2.com"));
newTokens.set(newTokens.size() - 1, newLink);
}
} else if (op.getName().equals("TJ")) {
// TJ contains a COSArray with COSStrings and COSFloat (padding)
COSArray previous = (COSArray) newTokens.get(newTokens.size() - 1);
String string = "";
for (int k = 0; k < previous.size(); k++) {
Object arrElement = previous.getObject(k);
if (arrElement instanceof COSString) {
COSString cosString = (COSString) arrElement;
String content = cosString.getString();
string += content;
}
}
// check if string contains a necessary link
if (string.equals("www.linkhouldbehere.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test.test.com"));
newTokens.set(newTokens.size() - 1, newLink);
} else if (string.startsWith("www.linkhouldbehere.com")) {
// some magic here to remove all indents and show new link from beginning.
// no rules. Just for test and it works here
COSArray newLink = (COSArray) newTokens.get(newTokens.size() - 1);
int size = newLink.size();
float f = ((COSFloat) newLink.get(size - 4)).floatValue();
for (int i = 0; i < size - 4; i++) {
newLink.remove(0);
}
newLink.set(0, new COSString("test.test.com"));
// number for padding of date from right place. Should be checked.
newLink.set(1, new COSFloat(f - 8000));
newTokens.set(newTokens.size() - 1, newLink);
}
}
}
newTokens.add(token);
}
// save replaced content inside a page
PDStream newContents = new PDStream(document);
OutputStream out = newContents.createOutputStream(COSName.FLATE_DECODE);
ContentStreamWriter writer = new ContentStreamWriter(out);
writer.writeTokens(newTokens);
out.close();
page.setContents(newContents);
// replace all links that have a pop-up line
pageNum++;
List<PDAnnotation> annotations = page.getAnnotations();
for (PDAnnotation annotation : annotations) {
PDAnnotation annot = annotation;
if (annot instanceof PDAnnotationLink) {
PDAnnotationLink link = (PDAnnotationLink) annot;
PDAction action = link.getAction();
if (action instanceof PDActionURI) {
PDActionURI uri = (PDActionURI) action;
String newURI = "www.test1.test1.com";
uri.setURI(newURI);
}
}
}
}
// save file
document.save(filePath.replace("file", "file_result"));
} catch (IOException e) {
e.printStackTrace();
} finally {
if (document != null) {
try {
document.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}编辑3.
pdf包含660 0 obj，其中包含必要的链接：
660 0 obj
<<
/BBox [0.0 792.0 612.0 0.0]
/Length 792
/Matrix [1.0 0.0 0.0 1.0 0.0 0.0]
/Resources <<
/ColorSpace <<
/CS0 [/ICCBased 21 0 R]
>>
/ExtGState <<
/GS0 22 0 R
>>
/Font <<
/T1_0 834 0 R
/T1_1 835 0 R
/T1_2 836 0 R
>>
/ProcSet [/PDF /Text]
>>
/Subtype /Form
>>
stream
/CS0 CS 0.412 0.416 0.423 SCN
0.25 w
/GS0 gs
q 1 0 0 1 72 78.425 cm
0 0 m
468 0 l
S
Q
/Artifact <</O /Layout >>BDC
BT
/CS0 cs 0.412 0.416 0.423 scn
/T1_0 1 Tf
0 Tc 0 Tw 0 Ts 100 Tz 0 Tr 8 0 0 8 72 64.8 Tm
[(Visit )35(O)7(ur site R)23.1(esear)15.1(ch Manager )20.1(on )20(the )12(web at )]TJ
ET
EMC
/Artifact <</O /Layout >>BDC
BT
/T1_1 1 Tf
8 0 0 8 237.0609 64.8 Tm
[(www)11(.lin)-14.9(kshou)-10(ldbeh)-8(ere)-7.9(ninechars)15.1(.com)]TJ
/Span<</ActualText<FEFF0009>>> BDC
( )Tj
EMC
31.954 0 Td
[(A)15(ugust 7)45.1(,)-5( 2015)]TJ
ET
EMC
/Artifact <</O /Layout >>BDC
BT
/T1_0 1 Tf
8 0 0 8 540 64.8 Tm
( )Tj
ET
EMC
/Artifact <</O /Layout >>BDC
BT
/T1_2 1 Tf
7 0 0 7 72 55.3 Tm
[(\251 2015 )29(CCH Incorporated and its af\037liates. )38.3(All rights r)12(eserv)8.1(ed.)]TJ
ET
EMC
endstream只有一个地方我发现它是从pdf文件中调用的。是从45号来的
/XObject <<
/Fm0 660 0 R
/Fm1 661 0 R
>>来自obj的全文：
45 0 obj
<<
/ArtBox [0.0 0.0 612.0 792.0]
/BleedBox [0.0 0.0 612.0 792.0]
/Contents 658 0 R
/CropBox [0.0 0.0 612.0 792.0]
/Group 659 0 R
/MediaBox [0.0 0.0 612.0 792.0]
/Parent 13 0 R
/Resources <<
/ColorSpace <<
/CS0 [/ICCBased 21 0 R]
>>
/ExtGState <<
/GS0 22 0 R
/GS1 23 0 R
>>
/Font <<
/T1_0 597 0 R
/T1_1 26 0 R
/T1_2 28 0 R
/T1_3 25 0 R
>>
/ProcSet [/PDF /Text]
/XObject <<
/Fm0 660 0 R
/Fm1 661 0 R
>>
>>
/Rotate 0
/StructParents 22
/Tabs /W
/Thumb 662 0 R
/TrimBox [0.0 0.0 612.0 792.0]
/Type /Page
/Annots []
>>
endobj一个问题是，我能得到这个660 0 obj并通过PDFBox处理它吗？因为看起来PDFStreamParser解析器对这个660 0对象一无所知。谢谢。
回答 1
Stack Overflow用户
回答已采纳
发布于 2015-09-18 11:23:09
对于PDFBox 2.0.0-快照。这是我的代码，在链接替换的情况下，我可以很好地工作。
非常感谢蒂尔曼·豪舍尔的帮助。
String filePath = "d:\\pdf\\file1.pdf"..。
public static void replaceLinksInPdf(String filePath) {
PDDocument document = null;
try {
document = PDDocument.load(new File(filePath));
// Decrypt a document
if (document.isEncrypted()) {
document.setAllSecurityToBeRemoved(true);
System.out.println(filePath + " Doc was decrypted");
}
// replace all links in a footer and a header in XObjects with /ProcSet [/PDF /Text]
// Note: these forms (and pattern objects too!) can have resources,
// i.e. have Form XObjects or patterns again.
// If so you need to use a recursion
for (int pageNum = 0; pageNum < document.getPages().getCount(); pageNum++) {
List<Object> newPdxTokens = new ArrayList<Object>();
// Get all XObjects from the page
Iterable<COSName> xobjs = document.getPage(pageNum).getResources().getXObjectNames();
for (COSName xobj : xobjs) {
boolean isHasTextStream = false;
PDXObject pdxObject = document.getPage(pageNum).getResources().getXObject(xobj);
// If a stream has not '/ProcSet [/PDF /Text]' line inside it has to be skipped
// isXobjectHasTextFieldInPdf has a recursion
if (pdxObject.getCOSObject() instanceof COSDictionary) {
isHasTextStream = isXobjectHasTextFieldInPdf((COSDictionary) pdxObject.getCOSObject());
}
if (pdxObject instanceof PDFormXObject && isHasTextStream) {
// Set stream from pdxObject
PDStream stream = pdxObject.getStream();
PDFStreamParser streamParser = new PDFStreamParser(stream.toByteArray());
streamParser.parse();
for (Object token : streamParser.getTokens()) {
if (token instanceof Operator) {
Operator op = (Operator) token;
if (op.getName().equals("Tj")) {
// Tj contains 1 COSString
COSString previous = (COSString) newPdxTokens.get(newPdxTokens.size() - 1);
String string = previous.getString();
// here can be any filters for checking a necessary string
if (string.equals("www.testlink.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test.test.com"));
newPdxTokens.set(newPdxTokens.size() - 1, newLink);
}
} else if (op.getName().equals("TJ")) {
// TJ contains a COSArray with COSStrings and COSFloat (padding)
COSArray previous = (COSArray) newPdxTokens.get(newPdxTokens.size() - 1);
String string = "";
for (int k = 0; k < previous.size(); k++) {
Object arrElement = previous.getObject(k);
if (arrElement instanceof COSString) {
COSString cosString = (COSString) arrElement;
String content = cosString.getString();
string += content;
}
}
// here can be any filters for checking a necessary string
// check if string contains a necessary link
if (string.equals("www.testlink.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test.test.com"));
newPdxTokens.set(newPdxTokens.size() - 1, newLink);
} else if (string.startsWith("www.testlink.com")) {
// this code should be changed. It can have some indenting problems that depend on COSFloat values
COSArray newLink = (COSArray) newPdxTokens.get(newPdxTokens.size() - 1);
int size = newLink.size();
float f = ((COSFloat) newLink.get(size - 4)).floatValue();
for (int i = 0; i < size - 4; i++) {
newLink.remove(0);
}
newLink.set(0, new COSString("test.test.com"));
// number for indenting from right place. Should be checked.
newLink.set(1, new COSFloat(f - 8000));
newPdxTokens.set(newPdxTokens.size() - 1, newLink);
}
}
}
// save tokens to a temporary List
newPdxTokens.add(token);
}
// save the replaced data back to the srteam
OutputStream out = stream.createOutputStream();
ContentStreamWriter writer = new ContentStreamWriter(out);
writer.writeTokens(newPdxTokens);
out.close();
}
}
}
// replace data from any text stream from pdf. XObjects not included.
int pageNum = 0;
for (PDPage page : document.getPages()) {
PDFStreamParser parser = new PDFStreamParser(page);
parser.parse();
// Get all tokens from the page
List<Object> tokens = parser.getTokens();
// Create a temporary List
List<Object> newTokens = new ArrayList<Object>();
for (Object token : tokens) {
if (token instanceof Operator) {
COSDictionary dictionary = ((Operator) token).getImageParameters();
if (dictionary != null) {
System.out.println(dictionary.toString());
}
}
if (token instanceof Operator) {
Operator op = (Operator) token;
if (op.getName().equals("Tj")) {
// Tj contains 1 COSString
COSString previous = (COSString) newTokens.get(newTokens.size() - 1);
String string = previous.getString();
// here can be any filters for checking a necessary string
if (string.equals("www.testlink.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test2.test2.com"));
newTokens.set(newTokens.size() - 1, newLink);
}
} else if (op.getName().equals("TJ")) {
// TJ contains a COSArray with COSStrings and COSFloat (padding)
COSArray previous = (COSArray) newTokens.get(newTokens.size() - 1);
String string = "";
for (int k = 0; k < previous.size(); k++) {
Object arrElement = previous.getObject(k);
if (arrElement instanceof COSString) {
COSString cosString = (COSString) arrElement;
String content = cosString.getString();
string += content;
}
}
// here can be any filters for checking a necessary string
if (string.equals("www.testlink.com")) {
COSArray newLink = new COSArray();
newLink.add(new COSString("test.test.com"));
newTokens.set(newTokens.size() - 1, newLink);
} else if (string.startsWith("www.testlink.com")) {
// this code should be changed. It can have some indenting problems that depend on COSFloat values
COSArray newLink = (COSArray) newTokens.get(newTokens.size() - 1);
int size = newLink.size();
float f = ((COSFloat) newLink.get(size - 4)).floatValue();
for (int i = 0; i < size - 4; i++) {
newLink.remove(0);
}
newLink.set(0, new COSString("test.test.com"));
// number for padding from right place. Should be checked.
newLink.set(1, new COSFloat(f - 8000));
newTokens.set(newTokens.size() - 1, newLink);
}
}
}
// save tokens to a temporary List
newTokens.add(token);
}
// save the replaced data back to the document's srteam
PDStream newContents = new PDStream(document);
OutputStream out = newContents.createOutputStream(COSName.FLATE_DECODE);
ContentStreamWriter writer = new ContentStreamWriter(out);
writer.writeTokens(newTokens);
out.close();
// save content
page.setContents(newContents);
// replace all links that have a pop-up line (It does not affect the visible text)
pageNum++;
List<PDAnnotation> annotations = page.getAnnotations();
for (PDAnnotation annotation : annotations) {
PDAnnotation annot = annotation;
if (annot instanceof PDAnnotationLink) {
PDAnnotationLink link = (PDAnnotationLink) annot;
PDAction action = link.getAction();
if (action instanceof PDActionURI) {
PDActionURI uri = (PDActionURI) action;
String newURI = "www.test1.test1.com";
uri.setURI(newURI);
}
}
}
}
// save document
document.save(filePath.replace("file", "file_result"));
} catch (IOException e) {
e.printStackTrace();
} finally {
if (document != null) {
try {
document.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}一种只处理文本流和跳过图像流的额外方法。它是从主方法"replaceLinksInPdf(String filePath)“调用的。
// Check if COSDictionary has '/ProcSet [/PDF /Text]' string in the stream
private static boolean isXobjectHasTextFieldInPdf(COSDictionary dictionary) {
boolean isHasTextField = false;
for (COSBase cosBase : dictionary.getValues()) {
// go to a recursion because COSDictionary can have COSDictionaries inside
if (cosBase instanceof COSDictionary) {
COSDictionary cosDictionaryNew = (COSDictionary) cosBase;
// check if '/ProcSet' has '/Text' param
if (cosDictionaryNew.containsKey(COSName.PROC_SET)) {
COSBase procSet = cosDictionaryNew.getDictionaryObject(COSName.PROC_SET);
if (procSet instanceof COSArray) {
for (COSBase procSetIterator : ((COSArray) procSet)) {
if (procSetIterator instanceof COSName
&& ((COSName) procSetIterator).getName().equals("Text")) {
return true;
}
}
} else if (procSet instanceof COSString && ((COSString) procSet).getString().equals("Text")) {
return true;
}
}
// go to the COSDictionary children
isHasTextField = isXobjectHasTextFieldInPdf(cosDictionaryNew);
}
}
return isHasTextField;
}它只是我的项目的一个测试变体。我将用项目的规则重构这段代码。你应该根据你的需要更换替代品。另外，我正在使用这个PDFBox 2.0.0库，大约一周，也许任何人都可以找到更简单的方法来执行一些代码。可以自由地进行代码评审，并发布更合适的变体。谢谢。
我在上面测试了40个PDF，其中只有2个必须进行深度处理，以防递归。所有40个文件都可以打开，可读的，看起来像以前的版本，除了链接。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/32617343
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