如何搜索某些特定的字符串或单词并在Java中的pdf文档中找到坐标 [英] How to search some specific string or a word and there coordinates from a pdf document in java
问题描述
我正在使用Pdfbox从pdf文件中搜索单词(或字符串)，我也想知道该单词的坐标.例如:-在pdf文件中，有一个类似"$ {abc}"的字符串.我想知道这个字符串的坐标.我尝试了一些示例，但根据我的理解并没有得到结果.结果显示了字符的坐标.
I am using Pdfbox to search a word(or String) from a pdf file and I also want to know the coordinates of that word. For example :- in a pdf file there is a string like "${abc}". I want to know the coordinates of this string. I Tried some couple of examples but didn't get the result according to me. in result it is displaying the coordinates of character.
代码在这里
@Override
protected void writeString(String string, List<TextPosition> textPositions) throws IOException {
for(TextPosition text : textPositions) {
System.out.println( "String[" + text.getXDirAdj() + "," +
text.getYDirAdj() + " fs=" + text.getFontSize() + " xscale=" +
text.getXScale() + " height=" + text.getHeightDir() + " space=" +
text.getWidthOfSpace() + " width=" +
text.getWidthDirAdj() + "]" + text.getUnicode());
}
}
我正在使用pdfbox 2.0
I am using pdfbox 2.0
推荐答案
PDFBox的 PDFTextStripper 类在其位置上仍具有位置文本(在将其简化为纯文本之前)的最后一种方法是该方法.
The last method in which PDFBox' PDFTextStripper class still has text with positions (before it is reduced to plain text) is the method
/**
* Write a Java string to the output stream. The default implementation will ignore the <code>textPositions</code>
* and just calls {@link #writeString(String)}.
*
* @param text The text to write to the stream.
* @param textPositions The TextPositions belonging to the text.
* @throws IOException If there is an error when writing the text.
*/
protected void writeString(String text, List<TextPosition> textPositions) throws IOException
应该在这里拦截，因为此方法会接收经过预处理的对象，特别是 sorted TextPosition 对象(如果一个对象请求 sorting 开始)
One should intercept here because this method receives pre-processed, in particular sorted TextPosition objects (if one requested sorting to start with).
(实际上，我更愿意在调用方法 writeLine 中进行拦截，该方法根据其参数的名称和局部变量具有的所有 TextPosition 实例> line 并每个 word 调用一次 writeString ；但是，不幸的是，PDFBox开发人员已将此方法声明为私有...好吧，也许直到最后2.0版时，这种方法才会更改.0版本... 轻按.更新:不幸的是，它在版本中没有更改... 叹气)
(Actually I would have preferred to intercept in the calling method writeLine which according to the names of its parameters and local variables has all the TextPosition instances of a line and calls writeString once per word; unfortunately, though, PDFBox developers have declared this method private... well, maybe this changes until the final 2.0.0 release... nudge, nudge. Update: Unfortunately it has not changed in the release... sigh)
此外，使用帮助器类将 TextPosition 实例的序列包装在类似 String 的类中以使代码更清晰是很有帮助的.
Furthermore it is helpful to use a helper class to wrap sequences of TextPosition instances in a String-like class to make code clearer.
记住这一点，就可以搜索这样的变量
With this in mind one can search for the variables like this
List<TextPositionSequence> findSubwords(PDDocument document, int page, String searchTerm) throws IOException
{
final List<TextPositionSequence> hits = new ArrayList<TextPositionSequence>();
PDFTextStripper stripper = new PDFTextStripper()
{
@Override
protected void writeString(String text, List<TextPosition> textPositions) throws IOException
{
TextPositionSequence word = new TextPositionSequence(textPositions);
String string = word.toString();
int fromIndex = 0;
int index;
while ((index = string.indexOf(searchTerm, fromIndex)) > -1)
{
hits.add(word.subSequence(index, index + searchTerm.length()));
fromIndex = index + 1;
}
super.writeString(text, textPositions);
}
};
stripper.setSortByPosition(true);
stripper.setStartPage(page);
stripper.setEndPage(page);
stripper.getText(document);
return hits;
}
使用此帮助程序类
public class TextPositionSequence implements CharSequence
{
public TextPositionSequence(List<TextPosition> textPositions)
{
this(textPositions, 0, textPositions.size());
}
public TextPositionSequence(List<TextPosition> textPositions, int start, int end)
{
this.textPositions = textPositions;
this.start = start;
this.end = end;
}
@Override
public int length()
{
return end - start;
}
@Override
public char charAt(int index)
{
TextPosition textPosition = textPositionAt(index);
String text = textPosition.getUnicode();
return text.charAt(0);
}
@Override
public TextPositionSequence subSequence(int start, int end)
{
return new TextPositionSequence(textPositions, this.start + start, this.start + end);
}
@Override
public String toString()
{
StringBuilder builder = new StringBuilder(length());
for (int i = 0; i < length(); i++)
{
builder.append(charAt(i));
}
return builder.toString();
}
public TextPosition textPositionAt(int index)
{
return textPositions.get(start + index);
}
public float getX()
{
return textPositions.get(start).getXDirAdj();
}
public float getY()
{
return textPositions.get(start).getYDirAdj();
}
public float getWidth()
{
TextPosition first = textPositions.get(start);
TextPosition last = textPositions.get(end);
return last.getWidthDirAdj() + last.getXDirAdj() - first.getXDirAdj();
}
final List<TextPosition> textPositions;
final int start, end;
}
仅输出其位置，宽度，最后一个字母和最后一个字母的位置，然后就可以使用
To merely output their positions, widths, final letters, and final letter positions, you can then use this
void printSubwords(PDDocument document, String searchTerm) throws IOException
{
System.out.printf("* Looking for '%s'\n", searchTerm);
for (int page = 1; page <= document.getNumberOfPages(); page++)
{
List<TextPositionSequence> hits = findSubwords(document, page, searchTerm);
for (TextPositionSequence hit : hits)
{
TextPosition lastPosition = hit.textPositionAt(hit.length() - 1);
System.out.printf(" Page %s at %s, %s with width %s and last letter '%s' at %s, %s\n",
page, hit.getX(), hit.getY(), hit.getWidth(),
lastPosition.getUnicode(), lastPosition.getXDirAdj(), lastPosition.getYDirAdj());
}
}
}
对于测试，我使用MS Word创建了一个小的测试文件:
For tests I created a small test file using MS Word:
此测试的输出
@Test
public void testVariables() throws IOException
{
try ( InputStream resource = getClass().getResourceAsStream("Variables.pdf");
PDDocument document = PDDocument.load(resource); )
{
System.out.println("\nVariables.pdf\n-------------\n");
printSubwords(document, "${var1}");
printSubwords(document, "${var 2}");
}
}
是
Variables.pdf
-------------
* Looking for '${var1}'
Page 1 at 164.39648, 158.06 with width 34.67856 and last letter '}' at 193.22, 158.06
Page 1 at 188.75699, 174.13995 with width 34.58806 and last letter '}' at 217.49, 174.13995
Page 1 at 167.49583, 190.21997 with width 38.000168 and last letter '}' at 196.22, 190.21997
Page 1 at 176.67009, 206.18 with width 35.667114 and last letter '}' at 205.49, 206.18
* Looking for '${var 2}'
Page 1 at 164.39648, 257.65997 with width 37.078552 and last letter '}' at 195.62, 257.65997
Page 1 at 188.75699, 273.74 with width 37.108047 and last letter '}' at 220.01, 273.74
Page 1 at 167.49583, 289.72998 with width 40.55017 and last letter '}' at 198.74, 289.72998
Page 1 at 176.67778, 305.81 with width 38.059418 and last letter '}' at 207.89, 305.81
我有点惊讶，因为如果发现 $ {var 2} 在同一行上，那么我会感到惊讶.毕竟，PDFBox代码使我假设我覆盖的方法 writeString 只检索 words ；看起来好像检索到的行部分比仅仅单词要长.
I was a bit surprised because ${var 2} has been found if on a single line; after all, PDFBox code made me assume the method writeString I overrode only retrieves words; it looks as if it retrieves longer parts of the line than mere words...
如果您需要从分组的 TextPosition 实例中获取其他数据，只需相应地增强 TextPositionSequence .
If you need other data from the grouped TextPosition instances, simply enhance TextPositionSequence accordingly.
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