前言
在 Open-Idea 的上个版本我们实现了将文档内容导出为 Word 格式和 PDF 格式，今天给大家揭秘下我是如何实现的。富文本文档支持导出为 Word 和 PDF 后端能做，其实前端也能做，我这里选中通过后端来实现，原因有以下两点：
- 后端处理大文本导出会更快
- 后端校验导出权限更方便
1. 下面是用到的依赖及版本
<!-- itext7html转pdf -->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>html2pdf</artifactId>
<version>5.0.3</version>
</dependency>
<!-- 中文字体支持 -->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>font-asian</artifactId>
<version>8.0.3</version>
</dependency>
<!-- html 转 word -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>4.1.2</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.2</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml-schemas</artifactId>
<version>4.1.2</version>
</dependency>
- Controller 处理请求
@PostMapping("/word")
public void exportWord(HttpServletRequest request, HttpServletResponse response, @RequestBody @Valid IdeaReportDTO reportDTO) throws Exception {
ideaDocExportService.exportWord(request, response, reportDTO);
}
@PostMapping("/pdf")
public void exportPdf(HttpServletRequest request, HttpServletResponse response, @RequestBody @Valid IdeaReportDTO reportDTO) throws Exception {
ideaDocExportService.exportPdf(request, response, reportDTO);
}
- 导出 Word
/**
* @param request
* @param response
* @param content 富文本内容（html）
* @param fileName 生成word文件
* @throws Exception
*/
private static void exportWord(HttpServletRequest request, HttpServletResponse response, String content, String fileName) throws Exception {
ByteArrayInputStream byteArrayInputStream = null;
POIFSFileSystem poifsFileSystem = null;
ServletOutputStream servletOutputStream = null;
try {
byte b[] = content.getBytes("GBK"); //这里是必须要设置编码的，不然导出中文就会乱码。
byteArrayInputStream = new ByteArrayInputStream(b);//将字节数组包装到流中
poifsFileSystem = new POIFSFileSystem();
DirectoryEntry directory = poifsFileSystem.getRoot();
directory.createDocument("WordDocument", byteArrayInputStream); //该步骤不可省略，否则会出现乱码。
//输出文件
request.setCharacterEncoding("utf-8");
response.setContentType("application/msword");//导出word格式
response.addHeader("Content-Disposition", "attachment;filename=" + fileName + ".doc");
servletOutputStream = response.getOutputStream();
poifsFileSystem.writeFilesystem(servletOutputStream);
} catch (Exception e) {
log.error("exportWord 生成word出错:",e);
resetResponse(response, e);
} finally {
byteArrayInputStream.close();
servletOutputStream.close();
poifsFileSystem.close();
}
}
private static 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);
}
- 导出 PDF
private static void exportPDF(HttpServletRequest request, HttpServletResponse response, String content, String fileName) throws IOException {
try{
//输出文件
request.setCharacterEncoding("utf-8");
response.setContentType("application/pdf");
response.setCharacterEncoding("utf-8");
String encodeFileName = URLEncoder.encode(fileName, "UTF-8");
response.setHeader("Content-disposition", "attachment;filename=" + encodeFileName);
InputStream stringStream = HtmlToPdfUtils.getStringStream(content);
HtmlToPdfUtils.convertToPdf(stringStream, "OpenByteCode", null, response.getOutputStream());
} catch (Exception e) {
log.error("exportPdf生成pdf出错:",e);
resetResponse(response, e);
}
}
/**
* Itext7转换工具类
*/
@Slf4j
public class HtmlToPdfUtils {
/**
* html转pdf
*
* @param inputStream 输入流
* @param waterMark 水印
* @param fontPath 字体路径，ttc后缀的字体需要添加<b>,0<b/>
* @param outputStream 输出流
* @date : 2021/1/15 14:07
*/
public static void convertToPdf(InputStream inputStream, String waterMark, String fontPath, OutputStream outputStream) throws IOException {
PdfWriter pdfWriter = new PdfWriter(outputStream);
PdfDocument pdfDocument = new PdfDocument(pdfWriter);
//设置为A4大小
pdfDocument.setDefaultPageSize(PageSize.A4);
//添加水印
pdfDocument.addEventHandler(PdfDocumentEvent.END_PAGE, new WaterMarkEventHandler(waterMark));
//添加分页器，但是目前分页器有点问题，总页数计算有问题
//pdfDocument.addEventHandler(PdfDocumentEvent.END_PAGE, new PageEventHandler());
//添加中文字体支持
ConverterProperties properties = new ConverterProperties();
FontProvider fontProvider = new FontProvider();
//设置字体
PdfFont sysFont = PdfFontFactory.createFont("STSongStd-Light", "UniGB-UCS2-H");
fontProvider.addFont(sysFont.getFontProgram(), "UniGB-UCS2-H");
//添加自定义字体，例如微软雅黑
if (StringUtils.isNotBlank(fontPath)) {
PdfFont microsoft = PdfFontFactory.createFont(fontPath, PdfEncodings.IDENTITY_H);
fontProvider.addFont(microsoft.getFontProgram(), PdfEncodings.IDENTITY_H);
}
properties.setFontProvider(fontProvider);
HtmlConverter.convertToPdf(inputStream, pdfDocument, properties);
pdfWriter.close();
pdfDocument.close();
}
/**
* 将一个字符串转化为输入流
* @param sInputString 字符串
* @return
*/
public static InputStream getStringStream(String sInputString) {
if (sInputString != null && !sInputString.trim().equals("")) {
try {
ByteArrayInputStream tInputStringStream = new ByteArrayInputStream(sInputString.getBytes());
return tInputStringStream;
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
}
生成的 PDF 支持水印功能
/**
* 水印
*/
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");
} 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();
}
}
导出 Word 效果
导出 PDF 效果
