使用freeMarKer和itextpdf将html转换成PDF

分手后的思念是犯贱 2024-02-28 06:02 48阅读 0赞

### 前言： ###

### 一、导入POM包 ###

<dependency>
                <groupId>org.freemarker</groupId>
                <artifactId>freemarker</artifactId>
                <version>2.3.31</version>
            </dependency>
            
            <dependency>
                <groupId>org.xhtmlrenderer</groupId>
                <artifactId>flying-saucer-pdf</artifactId>
                <version>9.1.22</version>
            </dependency>
            
            <dependency>
                <groupId>com.itextpdf</groupId>
                <artifactId>itextpdf</artifactId>
                <version>5.5.13.3</version>
            </dependency>

二、工具类

package com.ly.backend.common.utils;
    
    import com.itextpdf.text.pdf.BaseFont;
    import com.ly.backend.common.constants.FileTemplateConstant;
    import freemarker.template.Configuration;
    import freemarker.template.Template;
    import freemarker.template.TemplateException;
    import freemarker.template.TemplateExceptionHandler;
    import org.springframework.stereotype.Component;
    import org.xhtmlrenderer.pdf.ITextFontResolver;
    import org.xhtmlrenderer.pdf.ITextRenderer;
    
    import java.io.*;
    import java.nio.charset.StandardCharsets;
    import java.util.Map;
    
    /**
     * HTML 文件转 PDF 工具
     * @author cgy
     */
    public class JavaToPdfHtmlFreeMarkerUtil{
        private static Configuration freemarkerCfg = null;
    
        static {
            freemarkerCfg = new Configuration();
            //freemarker的模板目录
            try {
                freemarkerCfg.setDirectoryForTemplateLoading(new File(FilePathUtil.getCurrentPath()));
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        public static void createPdf(String content, String dest, String newFileName) throws IOException, DocumentException {
            // step 1
            Document document = new Document();
            File parentFile = new File(dest);
            if (!parentFile.exists()) {
                parentFile.mkdirs();
            }
            System.out.println("-------------->" + dest);
            // step 2
            PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(parentFile.getAbsolutePath() + File.separator + newFileName));
            // step 3
            document.open();
            // step 4
            XMLWorkerFontProvider fontImp = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
            fontImp.register(XinKeConstant.BID_PRICE_HTML_FONT_PATH);
            XMLWorkerHelper.getInstance().parseXHtml(writer, document,
                    new ByteArrayInputStream(content.getBytes()), null, Charset.forName("UTF-8"), fontImp);
            // step 5
            document.close();
    
        }
    
        public static void createPdf2(String content, HttpServletResponse response) throws IOException, DocumentException {
            // step 1
            Document document = new Document();
            // step 2
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            PdfWriter writer = PdfWriter.getInstance(document, outputStream);
            // step 3
            document.open();
            // step 4
            XMLWorkerFontProvider fontImp = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
            fontImp.register(XinKeConstant.BID_PRICE_HTML_FONT_PATH);
            XMLWorkerHelper.getInstance().parseXHtml(writer, document,
                    new ByteArrayInputStream(content.getBytes()), null, Charset.forName("UTF-8"), fontImp);
            // step 5
            document.close();
            byte[] pdfBytes = outputStream.toByteArray();
            response.setContentLength(pdfBytes.length);
            OutputStream os = response.getOutputStream();
            os.write(pdfBytes);
            os.flush();
            os.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
                Configuration cfg= new Configuration();
                Template template = cfg.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html模版生成PDF文件
         *
         * @param data
         * @param htmlTemplatePath
         * @param savePath
         * @throws IOException
         * @throws DocumentException
         */
        public static void convertPdfByHtml(Map<String, Object> data, String htmlTemplatePath, String savePath, String newFileName) throws IOException, DocumentException {
            String content = freeMarkerRender(data, htmlTemplatePath);
            createPdf(content, savePath, newFileName);
        }
        // 返回文档流下载
        public static void convertPdfByHtml2(Map<String, Object> data, String htmlTemplatePath, HttpServletResponse response) throws IOException, DocumentException {
            String content = freeMarkerRender(data, htmlTemplatePath);
            createPdf2(content,response);
        }
    }

### 三、使用(替换模板) ###

让前端写好html模板，只能使用原生的标签，然后替换文档里面的参数

// 替换html标签里的参数${parameter!}
    
    // 竖向遍历集合参数
    往tr上面添加        <#list companyName as companyName>
    结尾        </#list>
    // 横向遍历几何参数
    往td上加

后端代码：保存在本地

public ResponseDTO downloadReviewConfirmationForm() throws Exception {
            // 需要替换的参数
            Map<String, Object> data = getReviewConfirmationFormMap();
            String fileName = "生成的文件名称";
            String template = "模板的路径";
            // 设置响应内容类型为PDF
            String pdfPath = "保存在本地的地址";
            JavaToPdfHtmlFreeMarkerUtil.convertPdfByHtml(data, template, pdfPath, fileName + ".pdf");
            return ResponseDTO.success();
        }

返回文档流下载

public void downloadBidEvaluationReport(HttpServletResponse response) throws Exception {
            // 替换的参数
            Map<String, Object> data = downloadBidEvaluationReportMap();
            String fileName = "生成的文件名称";
            String template = "文档的地址";
    //        设置响应内容类型为PDF
            response.setContentType("application/pdf");
            response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(fileName, "UTF-8") + ".pdf");
            JavaToPdfHtmlFreeMarkerUtil.convertPdfByHtml2(data, template, response);
        }