如何使用iTextSharp转换HTML到PDF
本文关键字：PDF HTML 转换 何使用 iTextSharp | 更新日期: 2023-09-27 18:16:36
我想使用iTextSharp将下面的HTML转换为PDF，但不知道从哪里开始:
<style>
.headline{font-size:200%}
</style>
<p>
This <em>is </em>
<span class="headline" style="text-decoration: underline;">some</span>
<strong>sample<em> text</em></strong>
<span style="color: red;">!!!</span>
</p>
首先，HTML和PDF是不相关的，尽管它们是在同一时间创建的。HTML旨在传递更高层次的信息，如段落和表格。虽然有一些方法可以控制它，但最终还是由浏览器来绘制这些更高级的概念。PDF旨在传递文档，而文档必须无论在何处呈现都"看起来"相同。
在一个HTML文档中，你可能有一个100%宽的段落，这取决于你的显示器的宽度，它可能需要2行或10行，当你打印它时，它可能是7行，当你在手机上看它可能需要20行。但是，对于PDF文件，必须独立于呈现设备，因此无论屏幕大小如何，必须始终呈现完全相同的。
由于上面的必须， PDF不支持抽象的东西，如"表"或"段落"。PDF支持三种基本内容:文本、线条/形状和图像。(还有其他东西，如注释和电影，但我尽量保持简单)在PDF中，你不会说"这是一个段落，浏览器做你的事!"。相反，你可以说，"用这种字体在这个X,Y位置绘制文本，别担心，我之前已经计算过文本的宽度，所以我知道它会适合这条线"。你也不会说"这是一个表格"，而是说"在这个位置绘制这个文本，然后在我之前计算过的另一个位置绘制一个矩形，这样我就知道它会围绕文本"。
第二，iText和iTextSharp解析HTML和CSS。就是这样。ASP。. Net、MVC、Razor、Struts、Spring等都是HTML框架，但iText/iTextSharp完全不知道它们。DataGridViews、Repeaters、Templates、Views等也是一样，它们都是框架特定的抽象。从您选择的框架中获取HTML是您的责任，ittext不会帮助您。如果你得到一个异常说The document has no pages或你认为"ittext不是解析我的HTML"，这几乎是肯定的，你实际上没有HTML，你只是认为你有。
第三，已经存在多年的内置类是HTMLWorker，但是它已经被XMLWorker (Java/. net)所取代。零工作正在做的HTMLWorker不支持CSS文件，只有有限的支持最基本的CSS属性，实际上打破了某些标签。如果你在这个文件中没有看到HTML属性或CSS属性和值，那么HTMLWorker可能不支持它。XMLWorker有时可能更复杂，但这些复杂性也使其更具可扩展性。
下面是c#代码，展示了如何将HTML标记解析为ittext抽象，这些抽象会自动添加到您正在处理的文档中。c#和Java非常相似，所以转换起来应该相对容易。示例#1使用内置的HTMLWorker来解析HTML字符串。由于只支持内联样式，因此class="headline"被忽略，但其他所有内容都应该实际工作。例#2与第一个相同，只是它使用了XMLWorker。示例#3也解析了简单的CSS示例。
//Create a byte array that will eventually hold our final PDF
Byte[] bytes;
//Boilerplate iTextSharp setup here
//Create a stream that we can write to, in this case a MemoryStream
using (var ms = new MemoryStream()) {
//Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
using (var doc = new Document()) {
//Create a writer that's bound to our PDF abstraction and our stream
using (var writer = PdfWriter.GetInstance(doc, ms)) {
//Open the document for writing
doc.Open();
//Our sample HTML and CSS
var example_html = @"<p>This <em>is </em><span class=""headline"" style=""text-decoration: underline;"">some</span> <strong>sample <em> text</em></strong><span style=""color: red;"">!!!</span></p>";
var example_css = @".headline{font-size:200%}";
/**************************************************
* Example #1 *
* *
* Use the built-in HTMLWorker to parse the HTML. *
* Only inline CSS is supported. *
* ************************************************/
//Create a new HTMLWorker bound to our document
using (var htmlWorker = new iTextSharp.text.html.simpleparser.HTMLWorker(doc)) {
//HTMLWorker doesn't read a string directly but instead needs a TextReader (which StringReader subclasses)
using (var sr = new StringReader(example_html)) {
//Parse the HTML
htmlWorker.Parse(sr);
}
}
/**************************************************
* Example #2 *
* *
* Use the XMLWorker to parse the HTML. *
* Only inline CSS and absolutely linked *
* CSS is supported *
* ************************************************/
//XMLWorker also reads from a TextReader and not directly from a string
using (var srHtml = new StringReader(example_html)) {
//Parse the HTML
iTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, srHtml);
}
/**************************************************
* Example #3 *
* *
* Use the XMLWorker to parse HTML and CSS *
* ************************************************/
//In order to read CSS as a string we need to switch to a different constructor
//that takes Streams instead of TextReaders.
//Below we convert the strings into UTF8 byte array and wrap those in MemoryStreams
using (var msCss = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(example_css))) {
using (var msHtml = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(example_html))) {
//Parse the HTML
iTextSharp.tool.xml.XMLWorkerHelper.GetInstance().ParseXHtml(writer, doc, msHtml, msCss);
}
}
doc.Close();
}
}
//After all of the PDF "stuff" above is done and closed but **before** we
//close the MemoryStream, grab all of the active bytes from the stream
bytes = ms.ToArray();
}
//Now we just need to do something with those bytes.
//Here I'm writing them to disk but if you were in ASP.Net you might Response.BinaryWrite() them.
//You could also write the bytes to a database in a varbinary() column (but please don't) or you
//could pass them to another function for further PDF processing.
var testFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.pdf");
System.IO.File.WriteAllBytes(testFile, bytes);
2017的更新
对于HTML-to-PDF的需求有一个好消息。正如这个答案所示，W3C标准css-break-3将解决这个问题
…这是一项候选建议，计划在今年经过测试后成为最终建议。作为不太标准的解决方案，有c#插件，如print-css.rocks所示。
截至2018年，也有iText7(旧iTextSharp库的下一个迭代)及其HTML到PDF包可用:iText7 .pdfhtml
用法很简单:
HtmlConverter.ConvertToPdf(
new FileInfo(@"Path'to'Html'File.html"),
new FileInfo(@"Path'to'Pdf'File.pdf")
);
方法有更多的重载。
更新: ittext *系列产品具有双重许可模式:开源免费，商业使用付费。
@Chris Haas很好地解释了如何使用itextSharp将HTML转换为PDF，非常有帮助
我的地址是:
通过使用HtmlTextWriter我把html标签在HTML表+内联CSS我得到了我的PDF，因为我想没有使用XMLWorker。
Edit:添加示例代码:
ASPX页面:
<asp:Panel runat="server" ID="PendingOrdersPanel">
<!-- to be shown on PDF-->
<table style="border-spacing: 0;border-collapse: collapse;width:100%;display:none;" >
<tr><td><img src="abc.com/webimages/logo1.png" style="display: none;" width="230" /></td></tr>
<tr style="line-height:10px;height:10px;"><td style="display:none;font-size:9px;color:#10466E;padding:0px;text-align:right;">blablabla.</td></tr>
<tr style="line-height:10px;height:10px;"><td style="display:none;font-size:9px;color:#10466E;padding:0px;text-align:right;">blablabla.</td></tr>
<tr style="line-height:10px;height:10px;"><td style="display:none;font-size:9px;color:#10466E;padding:0px;text-align:right;">blablabla</td></tr>
<tr style="line-height:10px;height:10px;"><td style="display:none;font-size:9px;color:#10466E;padding:0px;text-align:right;">blablabla</td></tr>
<tr style="line-height:10px;height:10px;"><td style="display:none;font-size:11px;color:#10466E;padding:0px;text-align:center;"><i>blablabla</i> Pending orders report<br /></td></tr>
</table>
<asp:GridView runat="server" ID="PendingOrdersGV" RowStyle-Wrap="false" AllowPaging="true" PageSize="10" Width="100%" CssClass="Grid" AlternatingRowStyle-CssClass="alt" AutoGenerateColumns="false"
PagerStyle-CssClass="pgr" HeaderStyle-ForeColor="White" PagerStyle-HorizontalAlign="Center" HeaderStyle-HorizontalAlign="Center" RowStyle-HorizontalAlign="Center" DataKeyNames="Document#"
OnPageIndexChanging="PendingOrdersGV_PageIndexChanging" OnRowDataBound="PendingOrdersGV_RowDataBound" OnRowCommand="PendingOrdersGV_RowCommand">
<EmptyDataTemplate><div style="text-align:center;">no records found</div></EmptyDataTemplate>
<Columns>
<asp:ButtonField CommandName="PendingOrders_Details" DataTextField="Document#" HeaderText="Document #" SortExpression="Document#" ItemStyle-ForeColor="Black" ItemStyle-Font-Underline="true"/>
<asp:BoundField DataField="Order#" HeaderText="order #" SortExpression="Order#"/>
<asp:BoundField DataField="Order Date" HeaderText="Order Date" SortExpression="Order Date" DataFormatString="{0:d}"></asp:BoundField>
<asp:BoundField DataField="Status" HeaderText="Status" SortExpression="Status"></asp:BoundField>
<asp:BoundField DataField="Amount" HeaderText="Amount" SortExpression="Amount" DataFormatString="{0:C2}"></asp:BoundField>
</Columns>
</asp:GridView>
</asp:Panel>
protected void PendingOrdersPDF_Click(object sender, EventArgs e)
{
if (PendingOrdersGV.Rows.Count > 0)
{
//to allow paging=false & change style.
PendingOrdersGV.HeaderStyle.ForeColor = System.Drawing.Color.Black;
PendingOrdersGV.BorderColor = Color.Gray;
PendingOrdersGV.Font.Name = "Tahoma";
PendingOrdersGV.DataSource = clsBP.get_PendingOrders(lbl_BP_Id.Text);
PendingOrdersGV.AllowPaging = false;
PendingOrdersGV.Columns[0].Visible = false; //export won't work if there's a link in the gridview
PendingOrdersGV.DataBind();
//to PDF code --Sam
string attachment = "attachment; filename=report.pdf";
Response.ClearContent();
Response.AddHeader("content-disposition", attachment);
Response.ContentType = "application/pdf";
StringWriter stw = new StringWriter();
HtmlTextWriter htextw = new HtmlTextWriter(stw);
htextw.AddStyleAttribute("font-size", "8pt");
htextw.AddStyleAttribute("color", "Grey");
PendingOrdersPanel.RenderControl(htextw); //Name of the Panel
Document document = new Document();
document = new Document(PageSize.A4, 5, 5, 15, 5);
FontFactory.GetFont("Tahoma", 50, iTextSharp.text.BaseColor.BLUE);
PdfWriter.GetInstance(document, Response.OutputStream);
document.Open();
StringReader str = new StringReader(stw.ToString());
HTMLWorker htmlworker = new HTMLWorker(document);
htmlworker.Parse(str);
document.Close();
Response.Write(document);
}
}
当然包括iTextSharp对cs文件的引用
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.text.html.simpleparser;
using iTextSharp.tool.xml;
希望这对你有帮助!
谢谢
我使用以下代码创建PDF
protected void CreatePDF(Stream stream)
{
using (var document = new Document(PageSize.A4, 40, 40, 40, 30))
{
var writer = PdfWriter.GetInstance(document, stream);
writer.PageEvent = new ITextEvents();
document.Open();
// instantiate custom tag processor and add to `HtmlPipelineContext`.
var tagProcessorFactory = Tags.GetHtmlTagProcessorFactory();
tagProcessorFactory.AddProcessor(
new TableProcessor(),
new string[] { HTML.Tag.TABLE }
);
//Register Fonts.
XMLWorkerFontProvider fontProvider = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
fontProvider.Register(HttpContext.Current.Server.MapPath("~/Content/Fonts/GothamRounded-Medium.ttf"), "Gotham Rounded Medium");
CssAppliers cssAppliers = new CssAppliersImpl(fontProvider);
var htmlPipelineContext = new HtmlPipelineContext(cssAppliers);
htmlPipelineContext.SetTagFactory(tagProcessorFactory);
var pdfWriterPipeline = new PdfWriterPipeline(document, writer);
var htmlPipeline = new HtmlPipeline(htmlPipelineContext, pdfWriterPipeline);
// get an ICssResolver and add the custom CSS
var cssResolver = XMLWorkerHelper.GetInstance().GetDefaultCssResolver(true);
cssResolver.AddCss(CSSSource, "utf-8", true);
var cssResolverPipeline = new CssResolverPipeline(
cssResolver, htmlPipeline
);
var worker = new XMLWorker(cssResolverPipeline, true);
var parser = new XMLParser(worker);
using (var stringReader = new StringReader(HTMLSource))
{
parser.Parse(stringReader);
document.Close();
HttpContext.Current.Response.ContentType = "application /pdf";
if (base.View)
HttpContext.Current.Response.AddHeader("content-disposition", "inline;filename='"" + OutputFileName + ".pdf'"");
else
HttpContext.Current.Response.AddHeader("content-disposition", "attachment;filename='"" + OutputFileName + ".pdf'"");
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
HttpContext.Current.Response.WriteFile(OutputPath);
HttpContext.Current.Response.End();
}
}
}
这是我用作参考的链接。希望这对你有帮助!
使用ITextSharp将HTML转换为PDF
protected void Page_Load(object sender, EventArgs e)
{
try
{
string strHtml = string.Empty;
//HTML File path -http://aspnettutorialonline.blogspot.com/
string htmlFileName = Server.MapPath("~") + "''files''" + "ConvertHTMLToPDF.htm";
//pdf file path. -http://aspnettutorialonline.blogspot.com/
string pdfFileName = Request.PhysicalApplicationPath + "''files''" + "ConvertHTMLToPDF.pdf";
//reading html code from html file
FileStream fsHTMLDocument = new FileStream(htmlFileName, FileMode.Open, FileAccess.Read);
StreamReader srHTMLDocument = new StreamReader(fsHTMLDocument);
strHtml = srHTMLDocument.ReadToEnd();
srHTMLDocument.Close();
strHtml = strHtml.Replace("'r'n", "");
strHtml = strHtml.Replace("'0", "");
CreatePDFFromHTMLFile(strHtml, pdfFileName);
Response.Write("pdf creation successfully with password -http://aspnettutorialonline.blogspot.com/");
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
}
public void CreatePDFFromHTMLFile(string HtmlStream, string FileName)
{
try
{
object TargetFile = FileName;
string ModifiedFileName = string.Empty;
string FinalFileName = string.Empty;
/* To add a Password to PDF -http://aspnettutorialonline.blogspot.com/ */
TestPDF.HtmlToPdfBuilder builder = new TestPDF.HtmlToPdfBuilder(iTextSharp.text.PageSize.A4);
TestPDF.HtmlPdfPage first = builder.AddPage();
first.AppendHtml(HtmlStream);
byte[] file = builder.RenderPdf();
File.WriteAllBytes(TargetFile.ToString(), file);
iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(TargetFile.ToString());
ModifiedFileName = TargetFile.ToString();
ModifiedFileName = ModifiedFileName.Insert(ModifiedFileName.Length - 4, "1");
string password = "password";
iTextSharp.text.pdf.PdfEncryptor.Encrypt(reader, new FileStream(ModifiedFileName, FileMode.Append), iTextSharp.text.pdf.PdfWriter.STRENGTH128BITS, password, "", iTextSharp.text.pdf.PdfWriter.AllowPrinting);
//http://aspnettutorialonline.blogspot.com/
reader.Close();
if (File.Exists(TargetFile.ToString()))
File.Delete(TargetFile.ToString());
FinalFileName = ModifiedFileName.Remove(ModifiedFileName.Length - 5, 1);
File.Copy(ModifiedFileName, FinalFileName);
if (File.Exists(ModifiedFileName))
File.Delete(ModifiedFileName);
}
catch (Exception ex)
{
throw ex;
}
}
您可以下载示例文件。只需将要转换的html放在files文件夹中并运行即可。它将自动生成pdf文件，并将其放在同一个文件夹中。但是在您的情况下，您可以在htmlFileName变量中指定您的html路径。