java使用itext7实现html转pdf全代码完整示例

? ? 之前项目有个需求，系统实现自己的打印功能，基本上都是前端找了个框架搞的，我呢，就是配合处理一些前端不好处理的部分，但是新一期的需求评审中，前端提出了，前端自己生成pdf在数据量大的时候会很慢，自然这时候需要我这个后端介入了。虽然期间遇到过不少问题，但最后都解决了，至少解决的这一期的需求任务，后续可能在此基础上还会扩展，到时候再一一补充到这篇博客中。

? ? 首先，一开始也找了很多工具，都不是很合适，原因就不说了，最终敲定使用itext来实现html转pdf。

? ?html是前端自己生成，要注意的就是语法要合规（其中可能还有些标签属性不支持，但是这个得前端自己摸索改造，不在此处展开说明），不然很容易出现生成的pdf和html渲染的效果不一致的问题。

? 项目通过maven引入依赖

<!-- itext7html转pdf  -->
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>html2pdf</artifactId>
    <version>3.0.2</version>
</dependency>
<!-- 中文字体支持 -->
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>font-asian</artifactId>
    <version>7.1.13</version>
</dependency>

下面是具体相关代码

1水印部分

import com.itextpdf.kernel.colors.WebColors;
import com.itextpdf.kernel.events.Event;
import com.itextpdf.kernel.events.IEventHandler;
import com.itextpdf.kernel.events.PdfDocumentEvent;
import com.itextpdf.kernel.font.PdfFont;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.geom.Rectangle;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
import com.itextpdf.layout.Canvas;
import com.itextpdf.layout.element.Paragraph;
import com.itextpdf.layout.property.TextAlignment;
import com.itextpdf.layout.property.VerticalAlignment;

import java.io.IOException;

/**
 * @ClassName WaterMarkEventHandler
 * @Description 水印
 * @Author nw
 * @Date 2024/1/12 9:35
 * @Version 1.0
 */
public class WaterMarkEventHandler implements IEventHandler
{

    /**
     * 水印内容
     */
    private String waterMarkContent;

    /**
     * 一页中有几列水印
     */
    private int waterMarkX;

    /**
     * 一页中每列有多少水印
     */
    private int waterMarkY;

    public WaterMarkEventHandler(String waterMarkContent) {
        this(waterMarkContent, 5, 5);
    }

    public WaterMarkEventHandler(String waterMarkContent, int waterMarkX, int waterMarkY) {
        this.waterMarkContent = waterMarkContent;
        this.waterMarkX = waterMarkX;
        this.waterMarkY = waterMarkY;
    }

    @Override
    public void handleEvent(Event event) {

        PdfDocumentEvent documentEvent = (PdfDocumentEvent) event;
        PdfDocument document = documentEvent.getDocument();
        PdfPage page = documentEvent.getPage();
        Rectangle pageSize = page.getPageSize();

        PdfFont pdfFont = null;
        try {
            pdfFont = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H", false);
        } catch (IOException e) {
            e.printStackTrace();
        }

        PdfCanvas pdfCanvas = new PdfCanvas(page.newContentStreamAfter(), page.getResources(), document);

        Paragraph waterMark = new Paragraph(waterMarkContent).setOpacity(0.5f);
        Canvas canvas = new Canvas(pdfCanvas, pageSize)
                .setFontColor(WebColors.getRGBColor("lightgray"))
                .setFontSize(16)
                .setFont(pdfFont);

        for (int i = 0; i < waterMarkX; i++) {
            for (int j = 0; j < waterMarkY; j++) {
                canvas.showTextAligned(waterMark, (150 + i * 300), (160 + j * 150), document.getNumberOfPages(), TextAlignment.CENTER, VerticalAlignment.BOTTOM, 120);
            }
        }
        canvas.close();
    }
}

2.页码

import com.itextpdf.kernel.events.Event;
import com.itextpdf.kernel.events.IEventHandler;
import com.itextpdf.kernel.events.PdfDocumentEvent;
import com.itextpdf.kernel.font.PdfFont;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.geom.Rectangle;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
import com.itextpdf.layout.Canvas;
import com.itextpdf.layout.element.Paragraph;
import com.itextpdf.layout.property.TextAlignment;

import java.io.IOException;

/**
 * @ClassName PageEventHandler
 * @Description 页数
 * @Author nw
 * @Date 2024/1/12 9:38
 * @Version 1.0
 */
public class PageEventHandler implements IEventHandler {
    @Override
    public void handleEvent(Event event) {
        PdfDocumentEvent documentEvent = (PdfDocumentEvent) event;
        PdfDocument document = documentEvent.getDocument();
        PdfPage page = documentEvent.getPage();
        Rectangle pageSize = page.getPageSize();

        PdfFont pdfFont = null;
        try {
            pdfFont = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H", false);
        } catch (IOException e) {
            e.printStackTrace();
        }

        PdfCanvas pdfCanvas = new PdfCanvas(page.getLastContentStream(), page.getResources(), document);
        Canvas canvas = new Canvas(pdfCanvas, pageSize);
        float  x = (pageSize.getLeft() + pageSize.getRight()) / 2;
        float  y = pageSize.getBottom() + 15;
        Paragraph paragraph = new Paragraph("第" + document.getPageNumber(page) + "页/共" + document.getNumberOfPages() + "页")
                .setFontSize(10)
                .setFont(pdfFont);
        canvas.showTextAligned(paragraph, x, y, TextAlignment.CENTER);
        canvas.close();
    }
}

3.工具类

import com.itextpdf.html2pdf.ConverterProperties;
import com.itextpdf.html2pdf.HtmlConverter;
import com.itextpdf.kernel.events.PdfDocumentEvent;
import com.itextpdf.kernel.font.PdfFont;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.layout.font.FontProvider;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * @ClassName HtmlToPdfUtils
 * @Description
 * @Author nw
 * @Date 2024/1/12 9:40
 * @Version 1.0
 */
public class HtmlToPdfUtils
{
    public static void html2Pdf(InputStream inputStream, String waterMark, OutputStream outputStream) throws
            IOException
    {
        PdfWriter pdfWriter = new PdfWriter(outputStream);
        PdfDocument pdfDocument = new PdfDocument(pdfWriter);
        pdfDocument.addEventHandler(PdfDocumentEvent.END_PAGE, new WaterMarkEventHandler(waterMark));
        pdfDocument.addEventHandler(PdfDocumentEvent.END_PAGE, new PageEventHandler());

        ConverterProperties properties = new ConverterProperties();
        //添加中文字体支持
        FontProvider fontProvider = new FontProvider();
        PdfFont sysFont = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H", false);
        fontProvider.addFont(sysFont.getFontProgram(), "UniGB-UCS2-H");
        properties.setFontProvider(fontProvider);

        HtmlConverter.convertToPdf(inputStream, pdfDocument, properties);

        pdfWriter.close();
        pdfDocument.close();
    }
}

4.由于电脑端和手机端的要求不一样，所以写了两个接口，电脑端直接响应了文件流，手机端直接返回oss的一个地址，但是底层的逻辑是一致的，只是后续处理稍微不一样而已，下面两个接口代码示例，供大家参考。

4.1电脑端

控制层

    /**
     * web端用
     * @param file
     * @param param
     * @param response
     * @throws Exception
     */
    @PostMapping("/exportPdfWeb")
    public void exportPdfWeb(@RequestParam("file") MultipartFile file, @RequestParam("param") String param,HttpServletResponse response) throws Exception {
        JSONObject params = null;
        if(StringUtil.isEmpty(param)){
            params = new JSONObject();
        }else{
            params = JSON.parseObject(param);
        }
        String fileNamePrefix = params.getString("fileNamePrefix");
        try{
            String fileName = fileNamePrefix + "_" + DateUtil.getTimestamp("yyyyMMddHHmmss") + StringUtil.getUUID2Long() +".pdf";
            this.resolveResponse(response, fileName);
            customPrintModelService.exportPdfWeb(file, response.getOutputStream(),params);
        } catch (Exception e) {
           log.error("exportPdfWeb生成pdf出错:",e);
            this.resetResponse(response, e);
        }
    }

    /**
     * 客户端用
     * @param file
     * @param param
     * @return
     * @throws Exception
     */
    @PostMapping("/exportPdfClient")
    @ResponseBody
    public ApiResponse exportPdfClient(@RequestParam("file") MultipartFile file, @RequestParam("param") String param){
        JSONObject params = null;
        if(StringUtil.isEmpty(param)){
            params = new JSONObject();
        }else{
            params = JSON.parseObject(param);
        }
        if(!params.containsKey("fileNamePrefix") || StringUtil.isEmpty(params.getString("fileNamePrefix"))){
            return ApiResponse.failed(ApiResponse.CODE_FAIL_DEFAULT,"模板名称不能为空");
        }
        try{
            return customPrintModelService.exportPdfClient(file,params);
        } catch (Exception e) {
            log.error("exportPdfClient生成pdf出错:",e);
            return ApiResponse.failed(ApiResponse.CODE_FAIL_DEFAULT,"获取pdf路径失败");
        }
    }

    private void resolveResponse(HttpServletResponse response, String fileName) throws UnsupportedEncodingException
    {
        response.setContentType("application/pdf");
        response.setCharacterEncoding("utf-8");
        String encodeFileName = URLEncoder.encode(fileName, "UTF-8");
        response.setHeader("Content-disposition", "attachment;filename=" + encodeFileName);
        response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");
    }

    private void resetResponse(HttpServletResponse response, Exception exception)throws IOException {
        // 重置response
        response.reset();
        response.setContentType("application/json");
        response.setCharacterEncoding("utf-8");
        String result = "下载文件失败，" + exception.getMessage();
        response.getWriter().println(result);
    }

service层
?

    @Override
    public void exportPdfWeb(MultipartFile file, OutputStream outputStream,JSONObject params) throws IOException
    {
        //水印
        String waterMarkText = "";
        if(params.containsKey("waterMarkText")){
            waterMarkText = params.getString("waterMarkText");
        }
        InputStream inputStream = file.getInputStream();
        HtmlToPdfUtils.html2Pdf(inputStream, waterMarkText, outputStream);
    }

    @Override
    public ApiResponse exportPdfClient(MultipartFile file, JSONObject param) throws IOException
    {
        String fileNamePrefix = param.getString("fileNamePrefix");
        String fileName = fileNamePrefix + "_" + DateUtil.getTimestamp("yyyyMMddHHmmss") + StringUtil.getUUID2Long() +".pdf";
        String fullPath = PropertiesUtil.getInstance("system.properties").getValue("upload.root_path") + File.separator + fileName;
        //水印
        String waterMarkText = "";
        if(param.containsKey("waterMarkText")){
            waterMarkText = param.getString("waterMarkText");
        }
        InputStream inputStream = file.getInputStream();
        FileOutputStream fileOutputStream = null;
        try {
            fileOutputStream = new FileOutputStream(fullPath);
            HtmlToPdfUtils.html2Pdf(inputStream, waterMarkText, fileOutputStream);
        } catch (IOException e) {
            log.error("exportPdfClient生成pdf文件失败:",e);
            return ApiResponse.failed(ApiResponse.CODE_FAIL_DEFAULT,"生成pdf失败");
        }finally {
            try {
                fileOutputStream.close();
            } catch (IOException e) {
                log.error("exportPdfClient关闭文件流失败:",e);
            }
        }
        File localFile = new File(fullPath);
        String nowDate = DateUtil.DateTimeToString("yyyyMM", new Date());
        String fileKey = UserManager.getTenantId() + "/" + nowDate + "/print/" + fileName;
        boolean uploadFlag = FileStorgeHelper.syncUploadFileToOss(OssUsageEnum.USAGE_PRINT, localFile, fileKey, null);
        if (!uploadFlag) {
            log.info("上传文件到阿里云未成功");
            return ApiResponse.failed(ApiResponse.CODE_FAIL_DEFAULT,"上传文件到阿里云出错");
        }
        //上传成功 获取路径
        String fileUrl = FileStorgeHelper
                .generatePresignedUrl(OssUsageEnum.USAGE_PRINT, fileKey, 480, TimeUnit.MINUTES);
        return ApiResponse.success(fileUrl);
    }

另外接口调用图

电脑端：

手机端

最后说一下，目前产品的需求并未对纸张尺寸有要求，比如A3，A4，B2,itext中默认使用的是A4,具体怎么设置，等有需求再说吧，今天周六加班不想写了，准备下班。希望帮助到大家。