Conversion from HTML to PDF

Conversion from HTML to PDF
Maven dependency

<dependency>    <groupId>com.itextpdf</groupId>    <artifactId>itextpdf</artifactId>    <version>5.5.7</version></dependency><dependency>    <groupId>com.itextpdf.tool</groupId>    <artifactId>xmlworker</artifactId>    <version>5.5.7</version></dependency>

Class Diagram and API

Write (htmlContent: java. lang. String, OS: java. io. OutputStream): void

After converting the specified html into pdf content, write it to the specified output stream.

Html2PdfServiceImpl

HTML to PDF service implementation class

      
write (htmlContent: java.lang.String, os: java.io.OutputStream): void
    
Implementation: Convert the specified html into pdf content and write it to the specified output stream.
      
getIntaceHtml (htmlContent: String): String
    
The private method is used to obtain the complete html document. If only html fragments are input, you need to use the template to compile them.
      
doWrite (htmlContent: String, os: OutputStream): void
    
Private method: converts a complete html document to a pdf file and writes it to the specified output stream.

Code ihtml2workflow Service

Package cn. ljl. javaweb. demo. ckeditor. service; public interface ihtml2#service {/** prefix ID of the complete html content */public static final String INTACT_FLAG = "Html2PdfServiceImpl
Package cn. ljl. javaweb. demo. ckeditor. service; import java. io. byteArrayInputStream; import java. io. byteArrayOutputStream; import java. io. IOException; import java. io. inputStream; import java. io. outputStream; import java. nio. charset. charset; import com. itextpdf. text. extends entexception; public class html2?serviceimpl implements ihtml2=service {@ Override public void write (String htmlContent, OutputStream OS) {If (htmlContent = null | htmlContent. length () = 0) return; if (OS = null) return; htmlContent = getIntaceHtml (htmlContent); doWrite (htmlContent, OS );} /*** obtain the complete html content based on the provided html content. <br> * @ param htmlContent * @ return */private String getIntaceHtml (String htmlContent) {boolean intact = htmlContent. trim (). toLowerCase (). startsWith (INTACT_FLAG); if (! Intact) {htmlContent = TEMPLATE_HTML.replaceFirst ("\\\ \\{ content \\}", htmlContent) ;}return htmlContent ;}/ *** to implement write operations. <br> * @ param htmlContent * @ param OS */private void doWrite (String htmlContent, OutputStream OS) {InputStream is = new ByteArrayInputStream (htmlContent. getBytes (); com. itextpdf. text. document document = new com. itextpdf. text. document (); com.itext;.text=. specified writer = null; try {writer = com.itext;.text=. invalid writer. getInstance (document, OS); document. open (); com. itextpdf. tool. xml. XMLWorkerHelper. getInstance (). parseXHtml (writer, document, is, Charset. forName ("gbk");} catch (incluentexception e) {e. printStackTrace ();} catch (IOException e) {e. printStackTrace ();} writer. flush (); // SINOBEST HTML2PDF if we call writer. close (), may not generate pdf normally, or even encounter // Exception: The page 1 was requested but the document has only 0 pages. // writer. close (); document. close ();}}
Possible problems
1. Chinese character display problems
  
For a complete html document, you need to use css to set a default font for the entire document, such as the code snippet in the ihtml2workflow service template:
      
<style type='text/css'>body {font-family: SimSun;}</style>
  
2. Some content is blank
  
It may be that html documents use fonts that are not on the server. For example, if a div in an html document is set with the imitation font and is not installed on the machine, the corresponding content is blank when converted to pdf.