Java iText+FreeMarker生成PDF(HTML转PDF)
1.背景
在某些业务场景中,需要提供相关的电子凭证,比如网银/支付宝中转账的电子回单,签约的电子合同等。方便用户查看,下载,打印。目前常用的解决方案是,把相关数据信息,生成对应的pdf文件返回给用户。
本文源码:http://git.oschina.net/lujianing/java_pdf_demo
2.iText
iText是著名的开放源码的站点sourceforge一个项目,是用于生成PDF文档的一个java类库。通过iText不仅可以生成PDF或rtf的文档,而且可以将XML、Html文件转化为PDF文件。
iText 官网:http://itextpdf.com/
iText 开发文档: http://developers.itextpdf.com/developers-home
iText目前有两套版本iText5和iText7。iText5应该是网上用的比较多的一个版本。iText5因为是很多开发者参与贡献代码, 因此在一些规范和设计上存在不合理的地方。iText7是后来官方针对iText5的重构,两个版本差别还是挺大的。不过在实际使用中,一般用到的都比较 简单,所以不用特别拘泥于使用哪个版本。比如我们在http://mvnrepository.com/中搜索iText,出来的都是iText5的依赖。
来个最简单的例子:
添加依赖:
<!-- https://mvnrepository.com/artifact/com.itextpdf/itextpdf -->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.5.11</version>
</dependency>
测试代码:JavaToPdf
package com.lujianing.test;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdf {
private static final String DEST = "target/HelloWorld.pdf";
public static void main(String[] args) throws FileNotFoundException, DocumentException {
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(DEST));
document.open();
document.add(new Paragraph("hello world"));
document.close();
writer.close();
}
}
运行结果:
3.iText-中文支持
iText默认是不支持中文的,因此需要添加对应的中文字体,比如黑体simhei.ttf
可参考文档:http://developers.itextpdf.com/examples/font-examples/using-fonts#1227-tengwarquenya1.java
测试代码:JavaToPdfCN
package com.lujianing.test;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Font;
import com.itextpdf.text.FontFactory;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.BaseFont;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdfCN {
private static final String DEST = "target/HelloWorld_CN.pdf";
private static final String FONT = "simhei.ttf";
public static void main(String[] args) throws FileNotFoundException, DocumentException {
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(DEST));
document.open();
Font f1 = FontFactory.getFont(FONT, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
document.add(new Paragraph("hello world,我是鲁家宁", f1));
document.close();
writer.close();
}
}
输出结果:
4.iText-Html渲染
在一些比较复杂的pdf布局中,我们可以通过html去生成pdf
可参考文档:http://developers.itextpdf.com/examples/xml-worker-itext5/xml-worker-examples
添加依赖:
<!-- https://mvnrepository.com/artifact/com.itextpdf.tool/xmlworker -->
<dependency>
<groupId>com.itextpdf.tool</groupId>
<artifactId>xmlworker</artifactId>
<version>5.5.11</version>
</dependency>
添加模板:template.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<title>Title</title>
<style>
body{
font-family:SimHei;
}
.red{
color: red;
}
</style>
</head>
<body>
<div class="red">
你好,鲁家宁
</div>
</body>
</html>
测试代码:JavaToPdfHtml
package com.lujianing.test;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.tool.xml.XMLWorkerFontProvider;
import com.itextpdf.tool.xml.XMLWorkerHelper;
import com.lujianing.test.util.PathUtil;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.Charset;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdfHtml {
private static final String DEST = "target/HelloWorld_CN_HTML.pdf";
private static final String HTML = PathUtil.getCurrentPath()+"/template.html";
private static final String FONT = "simhei.ttf";
public static void main(String[] args) throws IOException, DocumentException {
// step 1
Document document = new Document();
// step 2
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(DEST));
// step 3
document.open();
// step 4
XMLWorkerFontProvider fontImp = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
fontImp.register(FONT);
XMLWorkerHelper.getInstance().parseXHtml(writer, document,
new FileInputStream(HTML), null, Charset.forName("UTF-8"), fontImp);
// step 5
document.close();
}
}
输出结果:
需要注意:
1.html中必须使用标准的语法,标签一定需要闭合
2.html中如果有中文,需要在样式中添加对应字体的样式
5.iText-Html-Freemarker渲染
在实际使用中,html内容都是动态渲染的,因此我们需要加入模板引擎支持,可以使用FreeMarker/Velocity,这里使用FreeMarker举例
添加FreeMarke依赖:
<!-- https://mvnrepository.com/artifact/org.freemarker/freemarker -->
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.19</version>
</dependency>
添加模板:template_freemarker.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<title>Title</title>
<style>
body{
font-family:SimHei;
}
.blue{
color: blue;
}
</style>
</head>
<body>
<div class="blue">
你好,${name}
</div>
</body>
</html>
测试代码:JavaToPdfHtmlFreeMarker
package com.lujianing.test;
import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.tool.xml.XMLWorkerFontProvider;
import com.itextpdf.tool.xml.XMLWorkerHelper;
import com.lujianing.test.util.PathUtil;
import freemarker.template.Configuration;
import freemarker.template.Template;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdfHtmlFreeMarker {
private static final String DEST = "target/HelloWorld_CN_HTML_FREEMARKER.pdf";
private static final String HTML = "template_freemarker.html";
private static final String FONT = "simhei.ttf";
private static Configuration freemarkerCfg = null;
static {
freemarkerCfg =new Configuration();
//freemarker的模板目录
try {
freemarkerCfg.setDirectoryForTemplateLoading(new File(PathUtil.getCurrentPath()));
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException, DocumentException {
Map<String,Object> data = new HashMap();
data.put("name","鲁家宁");
String content = JavaToPdfHtmlFreeMarker.freeMarkerRender(data,HTML);
JavaToPdfHtmlFreeMarker.createPdf(content,DEST);
}
public static void createPdf(String content,String dest) throws IOException, DocumentException {
// step 1
Document document = new Document();
// step 2
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(dest));
// step 3
document.open();
// step 4
XMLWorkerFontProvider fontImp = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
fontImp.register(FONT);
XMLWorkerHelper.getInstance().parseXHtml(writer, document,
new ByteArrayInputStream(content.getBytes()), null, Charset.forName("UTF-8"), fontImp);
// step 5
document.close();
}
/**
* freemarker渲染html
*/
public static String freeMarkerRender(Map<String, Object> data, String htmlTmp) {
Writer out = new StringWriter();
try {
// 获取模板,并设置编码方式
Template template = freemarkerCfg.getTemplate(htmlTmp);
template.setEncoding("UTF-8");
// 合并数据模型与模板
template.process(data, out); //将合并后的数据和模板写入到流中,这里使用的字符流
out.flush();
return out.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
return null;
}
}
输出结果:
目前为止,我们已经实现了iText通过Html模板生成Pdf的功能,但是实际应用中,我们发现iText并不能对高级的CSS样式进行解析,比如CSS中的position属性等,因此我们要引入新的组件
若中文变量还是不显示,则在pom.xml里添加如下:
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<!--增加的配置,过滤ttf文件的匹配-->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>2.7</version>
<configuration>
<encoding>UTF-8</encoding>
<nonFilteredFileExtensions>
<nonFilteredFileExtension>ttf</nonFilteredFileExtension>
</nonFilteredFileExtensions>
</configuration>
</plugin>
</plugins>
</build>
备注:工具类的方法 PathUtil.getCurrentPath() = "src/main/resources/",(这个对新手有用)
6.Flying Saucer-CSS高级特性支持
Flying Saucer is a pure-Java library for rendering arbitrary well-formed XML (or XHTML) using CSS 2.1 for layout and formatting, output to Swing panels, PDF, and images.
Flying Saucer是基于iText的,支持对CSS高级特性的解析。
添加依赖:
<!-- https://mvnrepository.com/artifact/org.xhtmlrenderer/flying-saucer-pdf -->
<dependency>
<groupId>org.xhtmlrenderer</groupId>
<artifactId>flying-saucer-pdf</artifactId>
<version>9.1.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.xhtmlrenderer/flying-saucer-pdf-itext5 -->
<dependency>
<groupId>org.xhtmlrenderer</groupId>
<artifactId>flying-saucer-pdf-itext5</artifactId>
<version>9.1.5</version>
</dependency>
添加模板:template_freemarker_fs.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"/>
<title>Title</title>
<style>
body{
font-family:SimHei;
}
.color{
color: green;
}
.pos{
position:absolute;
left:200px;
top:5px;
width: 200px;
font-size: 10px;
}
</style>
</head>
<body>
<img src="logo.png" width="600px"/>
<div class="color pos">
你好,${name}
</div>
</body>
</html>
测试代码:JavaToPdfHtmlFreeMarker
package com.lujianing.test.flyingsaucer;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.BaseFont;
import com.lujianing.test.util.PathUtil;
import freemarker.template.Configuration;
import freemarker.template.Template;
import org.xhtmlrenderer.pdf.ITextFontResolver;
import org.xhtmlrenderer.pdf.ITextRenderer;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdfHtmlFreeMarker {
private static final String DEST = "target/HelloWorld_CN_HTML_FREEMARKER_FS.pdf";
private static final String HTML = "template_freemarker_fs.html";
private static final String FONT = "simhei.ttf";
private static final String LOGO_PATH = "file://"+PathUtil.getCurrentPath()+"/logo.png";
private static Configuration freemarkerCfg = null;
static {
freemarkerCfg =new Configuration();
//freemarker的模板目录
try {
freemarkerCfg.setDirectoryForTemplateLoading(new File(PathUtil.getCurrentPath()));
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException, DocumentException, com.lowagie.text.DocumentException {
Map<String,Object> data = new HashMap();
data.put("name","鲁家宁");
String content = JavaToPdfHtmlFreeMarker.freeMarkerRender(data,HTML);
JavaToPdfHtmlFreeMarker.createPdf(content,DEST);
}
/**
* freemarker渲染html
*/
public static String freeMarkerRender(Map<String, Object> data, String htmlTmp) {
Writer out = new StringWriter();
try {
// 获取模板,并设置编码方式
Template template = freemarkerCfg.getTemplate(htmlTmp);
template.setEncoding("UTF-8");
// 合并数据模型与模板
template.process(data, out); //将合并后的数据和模板写入到流中,这里使用的字符流
out.flush();
return out.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
return null;
}
public static void createPdf(String content,String dest) throws IOException, DocumentException, com.lowagie.text.DocumentException {
ITextRenderer render = new ITextRenderer();
ITextFontResolver fontResolver = render.getFontResolver();
fontResolver.addFont(FONT, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
// 解析html生成pdf
render.setDocumentFromString(content);
//解决图片相对路径的问题
render.getSharedContext().setBaseURL(LOGO_PATH);
render.layout();
render.createPDF(new FileOutputStream(dest));
}
}
输出结果:
在某些场景下,html中的静态资源是在本地,我们可以使用render.getSharedContext().setBaseURL()加载文件资源,注意资源URL需要使用文件协议 "file://"。
对于生成的pdf页面大小,可以用css的@page属性设置。
7.PDF转图片
在某些场景中,我们可能只需要返回图片格式的电子凭证,我们可以使用Jpedal组件,把pdf转成图片
添加依赖:
<!-- https://mvnrepository.com/artifact/org.jpedal/jpedal-lgpl -->
<dependency>
<groupId>org.jpedal</groupId>
<artifactId>jpedal-lgpl</artifactId>
<version>4.74b27</version>
</dependency>
测试代码:JavaToPdfImgHtmlFreeMarker
package com.lujianing.test.flyingsaucer;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.BaseFont;
import com.lujianing.test.util.PathUtil;
import freemarker.template.Configuration;
import freemarker.template.Template;
import org.jpedal.PdfDecoder;
import org.jpedal.exception.PdfException;
import org.jpedal.fonts.FontMappings;
import org.xhtmlrenderer.pdf.ITextFontResolver;
import org.xhtmlrenderer.pdf.ITextRenderer;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
/**
* Created by lujianing on 2017/5/7.
*/
public class JavaToPdfImgHtmlFreeMarker {
private static final String DEST = "target/HelloWorld_CN_HTML_FREEMARKER_FS_IMG.png";
private static final String HTML = "template_freemarker_fs.html";
private static final String FONT = "simhei.ttf";
private static final String LOGO_PATH = "file://"+PathUtil.getCurrentPath()+"/logo.png";
private static final String IMG_EXT = "png";
private static Configuration freemarkerCfg = null;
static {
freemarkerCfg =new Configuration();
//freemarker的模板目录
try {
freemarkerCfg.setDirectoryForTemplateLoading(new File(PathUtil.getCurrentPath()));
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException, DocumentException, com.lowagie.text.DocumentException {
Map<String,Object> data = new HashMap();
data.put("name","鲁家宁");
String content = JavaToPdfImgHtmlFreeMarker.freeMarkerRender(data,HTML);
ByteArrayOutputStream pdfStream = JavaToPdfImgHtmlFreeMarker.createPdf(content);
ByteArrayOutputStream imgSteam = JavaToPdfImgHtmlFreeMarker.pdfToImg(pdfStream.toByteArray(),2,1,IMG_EXT);
FileOutputStream fileStream = new FileOutputStream(new File(DEST));
fileStream.write(imgSteam.toByteArray());
fileStream.close();
}
/**
* freemarker渲染html
*/
public static String freeMarkerRender(Map<String, Object> data, String htmlTmp) {
Writer out = new StringWriter();
try {
// 获取模板,并设置编码方式
Template template = freemarkerCfg.getTemplate(htmlTmp);
template.setEncoding("UTF-8");
// 合并数据模型与模板
template.process(data, out); //将合并后的数据和模板写入到流中,这里使用的字符流
out.flush();
return out.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
return null;
}
/**
* 根据模板生成pdf文件流
*/
public static ByteArrayOutputStream createPdf(String content) {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
ITextRenderer render = new ITextRenderer();
ITextFontResolver fontResolver = render.getFontResolver();
try {
fontResolver.addFont(FONT, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
} catch (com.lowagie.text.DocumentException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// 解析html生成pdf
render.setDocumentFromString(content);
//解决图片相对路径的问题
render.getSharedContext().setBaseURL(LOGO_PATH);
render.layout();
try {
render.createPDF(outStream);
return outStream;
} catch (com.lowagie.text.DocumentException e) {
e.printStackTrace();
} finally {
try {
outStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
/**
* 根据pdf二进制文件 生成图片文件
*
* @param bytes pdf二进制
* @param scaling 清晰度
* @param pageNum 页数
*/
public static ByteArrayOutputStream pdfToImg(byte[] bytes, float scaling, int pageNum,String formatName) {
//推荐的方法打开PdfDecoder
PdfDecoder pdfDecoder = new PdfDecoder(true);
FontMappings.setFontReplacements();
//修改图片的清晰度
pdfDecoder.scaling = scaling;
ByteArrayOutputStream out = new ByteArrayOutputStream();
try {
//打开pdf文件,生成PdfDecoder对象
pdfDecoder.openPdfArray(bytes); //bytes is byte[] array with PDF
//获取第pageNum页的pdf
BufferedImage img = pdfDecoder.getPageAsImage(pageNum);
ImageIO.write(img, formatName, out);
} catch (PdfException e) {
e.printStackTrace();
} catch (IOException e){
e.printStackTrace();
}
return out;
}
}
输出结果:
Jpedal支持将指定页Pdf生成图片,pdfDecoder.scaling设置图片的分辨率(不同分辨率下文件大小不同) ,支持多种图片格式,具体更多可自行研究
8.总结
对于电子凭证的技术方案,总结如下:
1.html模板+model数据,通过freemarker进行渲染,便于维护和修改
2.渲染后的html流,可通过Flying Saucer组件生成pdf文件流,或者生成pdf后再转成jpg文件流
3.在Web项目中,对应的文件流,可以通过ContentType设置,在线查看/下载,不需通过附件服务
9.纯前端解决方案
还有一种解决方案是使用PhantomJS
git地址: https://github.com/ariya/phantomjs
PhantomJS 是一个基于 WebKit 的服务器端 JavaScript API。它全面支持web而不需浏览器支持,其快速,原生支持各种Web标准: DOM 处理, CSS 选择器, JSON, Canvas, 和 SVG。 PhantomJS 可以用于 页面自动化 , 网络监测 , 网页截屏 ,以及 无界面测试 等。
具体方法可自行查询。