[英]iText - add content to existing PDF file
我想对 iText 执行以下操作:
(1)解析现有的PDF文件
(2) 向它添加一些数据,在文档的现有单页上(例如时间戳)
(3)写出文件
我似乎无法弄清楚如何使用 iText 做到这一点。 在伪代码中,我会这样做:
Document document = reader.read(input);
document.add(new Paragraph("my timestamp"));
writer.write(document, output);
但出于某种原因,iText 的 API 非常复杂,以至于我无法理解它。 PdfReader 实际上持有文档模型或其他东西(而不是吐出文档),您需要一个 PdfWriter 从中读取页面......是吗?
iText 有不止一种方法可以做到这一点。 PdfStamper
类是一种选择。 但我发现最简单的方法是创建一个新的 PDF 文档,然后将现有文档中的单个页面导入到新的 PDF 中。
// Create output PDF
Document document = new Document(PageSize.A4);
PdfWriter writer = PdfWriter.getInstance(document, outputStream);
document.open();
PdfContentByte cb = writer.getDirectContent();
// Load existing PDF
PdfReader reader = new PdfReader(templateInputStream);
PdfImportedPage page = writer.getImportedPage(reader, 1);
// Copy first page of existing PDF into output PDF
document.newPage();
cb.addTemplate(page, 0, 0);
// Add your new data / text here
// for example...
document.add(new Paragraph("my timestamp"));
document.close();
这将从templateInputStream
读取 PDF 并将其写出到outputStream
。 这些可能是文件流或内存流或任何适合您的应用程序的流。
Gutch 的代码很接近,但只有在以下情况下才能正常工作:
批准的方法是反过来做。 使用 PdfStamper 打开现有文档,并使用从 getOverContent() 返回的 PdfContentByte 将文本(以及您可能需要的任何其他内容)直接写入页面。 不需要第二份文件。
并且您可以使用 ColumnText 来处理布局等...无需使用 beginText(),setFontAndSize(),drawText(),drawText()...,endText() 搞砸和弄脏。
这是我能想象到的最复杂的场景:我有一个用 Ilustrator 创建并用 Acrobat 修改的 PDF 文件,我将使用此 Java 代码填充数据的 AcroFields (AcroForm),该 PDF 文件的结果与字段中的数据被修改添加文档。
实际上,在这种情况下,我正在动态生成一个背景,该背景将添加到 PDF 中,该背景也是使用具有未知数量数据或页面的文档动态生成的。
我正在使用 JBoss 并且此代码位于 JSP 文件中(应该可以在任何 JSP 网络服务器中使用)。
注意:如果您使用 IExplorer,您必须使用 POST 方法提交 HTTP 表单才能下载文件。 如果不是,您将在屏幕中看到 PDF 代码。 这不会发生在 Chrome 或 Firefox 中。
<%@ page import="java.io.*, com.lowagie.text.*, com.lowagie.text.pdf.*" %><%
response.setContentType("application/download");
response.setHeader("Content-disposition","attachment;filename=listaPrecios.pdf" );
// -------- FIRST THE PDF WITH THE INFO ----------
String str = "";
// lots of words
for(int i = 0; i < 800; i++) str += "Hello" + i + " ";
// the document
Document doc = new Document( PageSize.A4, 25, 25, 200, 70 );
ByteArrayOutputStream streamDoc = new ByteArrayOutputStream();
PdfWriter.getInstance( doc, streamDoc );
// lets start filling with info
doc.open();
doc.add(new Paragraph(str));
doc.close();
// the beauty of this is the PDF will have all the pages it needs
PdfReader frente = new PdfReader(streamDoc.toByteArray());
PdfStamper stamperDoc = new PdfStamper( frente, response.getOutputStream());
// -------- THE BACKGROUND PDF FILE -------
// in JBoss the file has to be in webinf/classes to be readed this way
PdfReader fondo = new PdfReader("listaPrecios.pdf");
ByteArrayOutputStream streamFondo = new ByteArrayOutputStream();
PdfStamper stamperFondo = new PdfStamper( fondo, streamFondo);
// the acroform
AcroFields form = stamperFondo.getAcroFields();
// the fields
form.setField("nombre","Avicultura");
form.setField("descripcion","Esto describe para que sirve la lista ");
stamperFondo.setFormFlattening(true);
stamperFondo.close();
// our background is ready
PdfReader fondoEstampado = new PdfReader( streamFondo.toByteArray() );
// ---- ADDING THE BACKGROUND TO EACH DATA PAGE ---------
PdfImportedPage pagina = stamperDoc.getImportedPage(fondoEstampado,1);
int n = frente.getNumberOfPages();
PdfContentByte background;
for (int i = 1; i <= n; i++) {
background = stamperDoc.getUnderContent(i);
background.addTemplate(pagina, 0, 0);
}
// after this everithing will be written in response.getOutputStream()
stamperDoc.close();
%>
还有另一种更简单的解决方案,可以解决您的问题。 这取决于您要添加的文本量。
// read the file
PdfReader fondo = new PdfReader("listaPrecios.pdf");
PdfStamper stamper = new PdfStamper( fondo, response.getOutputStream());
PdfContentByte content = stamper.getOverContent(1);
// add text
ColumnText ct = new ColumnText( content );
// this are the coordinates where you want to add text
// if the text does not fit inside it will be cropped
ct.setSimpleColumn(50,500,500,50);
ct.setText(new Phrase(str, titulo1));
ct.go();
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document,
new FileOutputStream("E:/TextFieldForm.pdf"));
document.open();
PdfPTable table = new PdfPTable(2);
table.getDefaultCell().setPadding(5f); // Code 1
table.setHorizontalAlignment(Element.ALIGN_LEFT);
PdfPCell cell;
// Code 2, add name TextField
table.addCell("Name");
TextField nameField = new TextField(writer,
new Rectangle(0,0,200,10), "nameField");
nameField.setBackgroundColor(Color.WHITE);
nameField.setBorderColor(Color.BLACK);
nameField.setBorderWidth(1);
nameField.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
nameField.setText("");
nameField.setAlignment(Element.ALIGN_LEFT);
nameField.setOptions(TextField.REQUIRED);
cell = new PdfPCell();
cell.setMinimumHeight(10);
cell.setCellEvent(new FieldCell(nameField.getTextField(),
200, writer));
table.addCell(cell);
// force upper case javascript
writer.addJavaScript(
"var nameField = this.getField('nameField');" +
"nameField.setAction('Keystroke'," +
"'forceUpperCase()');" +
"" +
"function forceUpperCase(){" +
"if(!event.willCommit)event.change = " +
"event.change.toUpperCase();" +
"}");
// Code 3, add empty row
table.addCell("");
table.addCell("");
// Code 4, add age TextField
table.addCell("Age");
TextField ageComb = new TextField(writer, new Rectangle(0,
0, 30, 10), "ageField");
ageComb.setBorderColor(Color.BLACK);
ageComb.setBorderWidth(1);
ageComb.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
ageComb.setText("12");
ageComb.setAlignment(Element.ALIGN_RIGHT);
ageComb.setMaxCharacterLength(2);
ageComb.setOptions(TextField.COMB |
TextField.DO_NOT_SCROLL);
cell = new PdfPCell();
cell.setMinimumHeight(10);
cell.setCellEvent(new FieldCell(ageComb.getTextField(),
30, writer));
table.addCell(cell);
// validate age javascript
writer.addJavaScript(
"var ageField = this.getField('ageField');" +
"ageField.setAction('Validate','checkAge()');" +
"function checkAge(){" +
"if(event.value < 12){" +
"app.alert('Warning! Applicant\\'s age can not" +
" be younger than 12.');" +
"event.value = 12;" +
"}}");
// add empty row
table.addCell("");
table.addCell("");
// Code 5, add age TextField
table.addCell("Comment");
TextField comment = new TextField(writer,
new Rectangle(0, 0,200, 100), "commentField");
comment.setBorderColor(Color.BLACK);
comment.setBorderWidth(1);
comment.setBorderStyle(PdfBorderDictionary.STYLE_SOLID);
comment.setText("");
comment.setOptions(TextField.MULTILINE |
TextField.DO_NOT_SCROLL);
cell = new PdfPCell();
cell.setMinimumHeight(100);
cell.setCellEvent(new FieldCell(comment.getTextField(),
200, writer));
table.addCell(cell);
// check comment characters length javascript
writer.addJavaScript(
"var commentField = " +
"this.getField('commentField');" +
"commentField" +
".setAction('Keystroke','checkLength()');" +
"function checkLength(){" +
"if(!event.willCommit && " +
"event.value.length > 100){" +
"app.alert('Warning! Comment can not " +
"be more than 100 characters.');" +
"event.change = '';" +
"}}");
// add empty row
table.addCell("");
table.addCell("");
// Code 6, add submit button
PushbuttonField submitBtn = new PushbuttonField(writer,
new Rectangle(0, 0, 35, 15),"submitPOST");
submitBtn.setBackgroundColor(Color.GRAY);
submitBtn.
setBorderStyle(PdfBorderDictionary.STYLE_BEVELED);
submitBtn.setText("POST");
submitBtn.setOptions(PushbuttonField.
VISIBLE_BUT_DOES_NOT_PRINT);
PdfFormField submitField = submitBtn.getField();
submitField.setAction(PdfAction
.createSubmitForm("",null, PdfAction.SUBMIT_HTML_FORMAT));
cell = new PdfPCell();
cell.setMinimumHeight(15);
cell.setCellEvent(new FieldCell(submitField, 35, writer));
table.addCell(cell);
// Code 7, add reset button
PushbuttonField resetBtn = new PushbuttonField(writer,
new Rectangle(0, 0, 35, 15), "reset");
resetBtn.setBackgroundColor(Color.GRAY);
resetBtn.setBorderStyle(
PdfBorderDictionary.STYLE_BEVELED);
resetBtn.setText("RESET");
resetBtn
.setOptions(
PushbuttonField.VISIBLE_BUT_DOES_NOT_PRINT);
PdfFormField resetField = resetBtn.getField();
resetField.setAction(PdfAction.createResetForm(null, 0));
cell = new PdfPCell();
cell.setMinimumHeight(15);
cell.setCellEvent(new FieldCell(resetField, 35, writer));
table.addCell(cell);
document.add(table);
document.close();
}
class FieldCell implements PdfPCellEvent{
PdfFormField formField;
PdfWriter writer;
int width;
public FieldCell(PdfFormField formField, int width,
PdfWriter writer){
this.formField = formField;
this.width = width;
this.writer = writer;
}
public void cellLayout(PdfPCell cell, Rectangle rect,
PdfContentByte[] canvas){
try{
// delete cell border
PdfContentByte cb = canvas[PdfPTable
.LINECANVAS];
cb.reset();
formField.setWidget(
new Rectangle(rect.left(),
rect.bottom(),
rect.left()+width,
rect.top()),
PdfAnnotation
.HIGHLIGHT_NONE);
writer.addAnnotation(formField);
}catch(Exception e){
System.out.println(e);
}
}
}
how-to-update-a-pdf-without-creating-a-new-pdf
iText 7,请注意版本
PdfReader reader = new PdfReader(src);
PdfWriter writer = new PdfWriter(dest);
PdfDocument pdfDoc = new PdfDocument(reader, writer);
//manipulate pdf…
pdfDoc.close();
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