Pdf文件未正确加载由servlet创建 [英] Pdf file not loading properly created by the servlet
问题描述
朋友们，我已经实现了一个jsp表单，它接受pdf文件的标题，描述和内容等输入。当提交jsp表单时，pdf是在servlet的帮助下使用itext创建的，名为'pdfGenServlet.java'。
Friends, I am have implemented a jsp form which takes inputs like title, description and content of the pdf file. When the jsp form is submitted, the pdf is created using itext with the help of the servlet called 'pdfGenServlet.java'.
我的jsp表单是
<form action="pdfGenServlet1" method="get" enctype="application/x-www-form-urlencoded">
<!-- input notes title-->
<div class="form-group">
<div class="input-group">
<input type="text" class="form-control" placeholder="Title of the notes" name="title">
</div>
</div>
<!-- input notes description-->
<div class="form-group">
<div class="input-group">
<input type="text" class="form-control" placeholder="Enter short description" name="description">
</div>
</div>
<div class="form-group">
<textarea name="content" id="myEditor"></textarea>
<div id="button-panel" class="panel panel-default">
<p>
<button type="submit" class="btn btn-primary "><span class="glyphicon glyphicon-plus"></span><strong> Create Note</strong></button>
<button class="btn btn-primary" type="reset"><strong>Reset</strong></button>
</p><!-- buttons -->
</div><!-- panel Button -->
</div>
</form>
servlet'pdfGenServlet.java'
The servlet 'pdfGenServlet.java'
//imports for itext
import java.io.FileOutputStream;
import java.io.StringReader;
import com.itextpdf.text.BaseColor;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Font;
import com.itextpdf.text.Font.FontFamily;
import com.itextpdf.text.Document;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.html.simpleparser.HTMLWorker; // deprecated
import com.itextpdf.text.pdf.PdfWriter;
//servlet imports
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//File handling and java util
import java.io.ByteArrayOutputStream;
import java.io.OutputStream;
import java.util.Date;
@WebServlet("/pdfGenServlet1")
public class pdfGenServlet1 extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
//Font for using with itext
Font bfBold18 = new Font(FontFamily.TIMES_ROMAN, 18, Font.BOLD, new BaseColor(0, 0, 0));
Font bfBold12 = new Font(FontFamily.TIMES_ROMAN, 12, Font.BOLD, new BaseColor(0, 0, 0));
String title = request.getParameter("title");
String description = request.getParameter("description");
String notes_content = request.getParameter("content");
Date date = new Date();
Document document = new Document(PageSize.A4);
PdfWriter.getInstance(document, new FileOutputStream("C://BEProject//PreparedNotes//testpdf1.pdf"));
HTMLWorker htmlWorker = new HTMLWorker(document);
document.open();
document.addAuthor("Real Gagnon");
document.addCreator("Real's HowTo");
document.addSubject("Thanks for your support");
document.addCreationDate();
document.addTitle("Please read this");
//
document.addCreationDate();
document.add(new Paragraph("TITLE: ", bfBold18));
document.add(new Paragraph(title,bfBold12));
document.add(new Paragraph("\n"));
document.add(new Paragraph(String.format("Created on: " + date.toString())));
document.add(new Paragraph("DESCRIPTION: ", bfBold18));
document.add(new Paragraph(description,bfBold12));
document.add(new Paragraph("\n"));
htmlWorker.parse(new StringReader(notes_content));
// step 5
document.close();
response.setHeader("Content-disposition", "attachment; filename= testpdf1.pdf");
response.setContentType("application/pdf");
} catch (DocumentException e) {
e.printStackTrace();
}
}
}
请自己尝试代码。您将看到创建的pdf文件会自动下载，但在打开时会显示加载但不会像这样加载
} Please try the code urself. You'll see the pdf file created downloads automatically but when opened it show loading but doesnt loads like this
当在pdfGenServlet中显示的同一文件位于'C：// BEProject //时PreparedNotes // testpdf1.pdf'。
手动打开testpdf1.pdf时，它会正常打开。
请帮助
When the same file made at directory displayed in pdfGenServlet at 'C://BEProject//PreparedNotes//testpdf1.pdf' . When the testpdf1.pdf is opened manually it opens properly. Please help
推荐答案
您在本地磁盘上创建PDF并设置一些发送到浏览器的标题。您不会向浏览器发送任何字节，因此您不应期望在浏览器中看到任何内容。这与您描述的行为一致。
You create a PDF on your local disk and you set some headers that are sent to the browser. You do not send any bytes to the browser, hence you should not expect to see anything in your browser. This is consistent with the behavior you describe.
在另一个答案中，有人告诉您将PDF字节写入 HttpServletResponse 。最简单的方法是遵循我写的关于iText的书的例子，更具体地说， Hello 示例：
In another answer, somebody tells you to write the PDF bytes to the HttpServletResponse. The most simple way to do this, is to follow the example from the book I wrote about iText, more specifically, the Hello example:
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("application/pdf");
try {
// step 1
Document document = new Document();
// step 2
PdfWriter.getInstance(document, response.getOutputStream());
// step 3
document.open();
// step 4
document.add(new Paragraph("Hello World"));
document.add(new Paragraph(new Date().toString()));
// step 5
document.close();
} catch (DocumentException de) {
throw new IOException(de.getMessage());
}
}
你可以尝试这个例子这里。
在一个理想的世界中，这可行适用于所有浏览器不幸的是，并非所有浏览器都是相同的，因此您可能希望通过遵循 PdfServlet 示例：
In an ideal world, this would work for all browsers. Unfortunately, not all browsers are created alike, hence you may want to code in a more defensive way by following the PdfServlet example:
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
// Get the text that will be added to the PDF
String text = request.getParameter("text");
if (text == null || text.trim().length() == 0) {
text = "You didn't enter any text.";
}
// step 1
Document document = new Document();
// step 2
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfWriter.getInstance(document, baos);
// step 3
document.open();
// step 4
document.add(new Paragraph(String.format(
"You have submitted the following text using the %s method:",
request.getMethod())));
document.add(new Paragraph(text));
// step 5
document.close();
// setting some response headers
response.setHeader("Expires", "0");
response.setHeader("Cache-Control",
"must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma", "public");
// setting the content type
response.setContentType("application/pdf");
// the contentlength
response.setContentLength(baos.size());
// write ByteArrayOutputStream to the ServletOutputStream
OutputStream os = response.getOutputStream();
baos.writeTo(os);
os.flush();
os.close();
// if you also want to write these bytes to a file, add:
OutputStream fos = new FileOutputStream(pathToFile);
baos.writeTo(fos);
fos.flush();
fos.close();
}
catch(DocumentException e) {
throw new IOException(e.getMessage());
}
}
你可以尝试这个servlet 这里。如您所见，我们现在首先在内存中创建文件。我们这样做，以便我们可以设置内容长度的标题（某些浏览器需要这样）。我还设置了一些可能没有必要的其他标题，但多年来根据数千名iText用户的反馈将其添加到我的示例中。
You can try this servlet here. As you can see, we now create the file in memory first. We do so, so that we can set the header for the content length (some browsers require this). I've also set some other headers that may not be necessary, but that were added to my example over the years based on feedback of thousands of iText users.
这篇关于Pdf文件未正确加载由servlet创建的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
