itext7 html转pdf实现

公司最近做一个交易所项目,里面涉及一个需求就是将html模板,在填充数据后转换为pdf,这样防止数据更改,下面是具体实现

1 pom文件

　　　　　<dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>html2pdf</artifactId>
            <version>2.0.2</version>
        </dependency>
        <dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>font-asian</artifactId>
            <version>7.1.2</version>
        </dependency>             

2 html转pdf

itext7进行html转换使用类:com.itextpdf.html2pdf.HtmlConverter
　　它主要有三类操作:convertToPdf直接转换为pdf文件
　　　　　　　　　　 convertToDocument转为document文档,这样有利于进行pdf页面调整
　　　　　　　　　　 convertToElements拆解pdf标签
我这里因为html转换后会有多页,这里通过convertToDocument调整页面大小,在一页上显示所有内容;
同时我使用ByteArrayOutputStream类,这个的好处是不在本地生成文件,减少磁盘操作,但是这种方式也有人说效率不高,使用者可以斟酌后使用.
因为spring boot存在打包后resources目录文件获取不到的问题,所以我将pdf依赖的字体文件放到项目的根路径下(跟src目录同级).

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package com.ssth.exchanage.excenter.common.uitls;   import java.io.ByteArrayOutputStream; import java.io.FileNotFoundException; import java.io.IOException;   import com.itextpdf.html2pdf.ConverterProperties; import com.itextpdf.html2pdf.HtmlConverter; import com.itextpdf.html2pdf.resolver.font.DefaultFontProvider; import com.itextpdf.kernel.colors.Color; import com.itextpdf.kernel.geom.PageSize; import com.itextpdf.kernel.geom.Rectangle; import com.itextpdf.kernel.pdf.PdfDocument; import com.itextpdf.kernel.pdf.PdfPage; import com.itextpdf.kernel.pdf.PdfWriter; import com.itextpdf.kernel.pdf.canvas.PdfCanvas; import com.itextpdf.kernel.pdf.canvas.draw.ILineDrawer; import com.itextpdf.layout.Document; import com.itextpdf.layout.element.LineSeparator;   public class PDFUtil {     private static final String FONT = "./pdf/font/NotoSansCJKsc-Regular.otf";       /**      * @Description 将html转换为pdf文件      * @param html html页面字符串      * @return      * @throws FileNotFoundException      * @throws IOException      */     public ByteArrayOutputStream html2Pdf(String html) throws FileNotFoundException, IOException {         ConverterProperties props = new ConverterProperties();         DefaultFontProvider defaultFontProvider = new DefaultFontProvider(false, false, false);         defaultFontProvider.addFont(font);         props.setFontProvider(defaultFontProvider);         ByteArrayOutputStream bao = new ByteArrayOutputStream();         PdfWriter writer = new PdfWriter(bao);         PdfDocument pdf = new PdfDocument(writer);         pdf.setDefaultPageSize(new PageSize(595, 14400));         Document document = HtmlConverter.convertToDocument(html, pdf, props);         EndPosition endPosition = new EndPosition();         LineSeparator separator = new LineSeparator(endPosition);         document.add(separator);         document.getRenderer().close();         PdfPage page = pdf.getPage(1);         float y = endPosition.getY() - 36;         page.setMediaBox(new Rectangle(0, y, 595, 14400 - y));         document.close();         return bao;     }       /**      * 定义操作区域      */     class EndPosition implements ILineDrawer {         // y坐标         protected float y;           /**          * @Description: 获取y坐标          * @return          */         public float getY() {             return y;         }           /**          * @Description: 操作画布特定区域          * @param pdfCanvas:操作画布          * @param rect:操作区域          */         @Override         public void draw(PdfCanvas pdfCanvas, Rectangle rect) {             this.y = rect.getY();         }           /**          * @Description: 获取行颜色          * @return          */         @Override         public Color getColor() {             return null;         }           /**          * @Description: 获取行宽          * @return          */         @Override         public float getLineWidth() {             return 0;         }           /**          * @Description: 设置行颜色          * @param color          */         @Override         public void setColor(Color color) {         }           /**          * @Description: 设置行宽          * @param lineWidth:宽度          */         @Override         public void setLineWidth(float lineWidth) {         }     } }

3 流响应

核心是通过ByteArrayOutputStream.writeTo(HttpServletResponse.getOutputStream())方法

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package com.huishi;   import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Service; import com.ssth.exchanage.excenter.common.exception.ResException; import com.ssth.exchanage.excenter.common.uitls.DateUtil; import com.ssth.exchanage.excenter.common.uitls.PDFUtil; import com.ssth.exchanage.excenter.controller.response.RecordApplyParamRep; import com.ssth.exchanage.excenter.service.ProductRecordService;   @Service public class ProductRecordServiceImp implements ProductRecordService {       /**      * @Description 打印备案申请书      * @param res http响应      */     @Override     public void printRecord(HttpServletResponse res){         try {         　　String htmlStr = FileUtil.readFile(null);         　　PDFUtil pdfUtil = new PDFUtil();         　　ByteArrayOutputStream stream = pdfUtil.html2Pdf(htmlStr);         　　res.setHeader("Expires", "0");         　　res.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");             　　res.setHeader("Pragma", "public");         　　res.setContentType("application/pdf");         　　OutputStream os = res.getOutputStream();         　　stream.writeTo(os);             　　os.flush();             　　os.close();         } catch (IOException e) {         　　log.error("printRecord {}",e.getMessage());         　　throw new ResException("-1","服务内部错误,请稍后再试!");         }     } }

备注:

itext7解决中文显示问题有两种解决方式:

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1 引入对应的语言包,火狐浏览器预览生成的pdf可能存在部分中文乱码问题,同时因为加载了语言包,生成的pdf更大 使用NotoSansCJKsc-Regular.otf,同时在pom中引入com.itextpdf.font-asian包. 2 设置字体:通过默认字体生成,pdf文件和html大小几乎相同,不存在浏览器预览乱码问题 PdfFont font = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H", false);

 

使用示例链接: https://github.com/liulei3/html2pdf　

参考文件:

html转pdf: https://developers.itextpdf.com/content/itext-7-examples/itext-7-converting-html-pdf

流响应:https://developers.itextpdf.com/content/best-itext-questions-stackoverview/general-questions-about-itext/itext7-how-can-i-serve-pdf-browser-without-storing-file-server-side