SpringBoot集成itext导出PDF的过程

        <!-- PDF导出 -->
        <dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itextpdf</artifactId>
            <version>5.5.11</version>
        </dependency>
        <dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itext-asian</artifactId>
            <version>5.2.0</version>
        </dependency>

    // 导出pdf
    @GetMapping("/exportPdf")
    public void exportPdf(HttpServletResponse response) throws DocumentException, IOException {
        byte[] pdfBytes = userPdfExportService.exportUsersToPdf();
        String filename = "用户信息.pdf";
        String encodedFilename = URLEncoder.encode(filename, StandardCharsets.UTF_8.toString()).replace("+", "%20");
        response.setContentType("application/pdf");
        response.setHeader("Content-Disposition", "attachment; filename=" + encodedFilename);
        response.setContentLength(pdfBytes.length);
        response.getOutputStream().write(pdfBytes);
        response.getOutputStream().flush();
        response.getOutputStream().close();
    }

@Service
public class UserPdfExportService {
    @Autowired
    private ISysUserService sysUserService;
    public byte[] exportUsersToPdf() throws DocumentException, IOException {
        //查询要导出的数据
        List<SysUser> users = sysUserService.selectUserList(new SysUser());
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Document document = new Document();
        PdfWriter.getInstance(document, baos);
        document.open();
        // 添加标题
        document.add(new Paragraph("用户列表"));
        // 加载自定义字体
        InputStream is = getClass().getResourceAsStream("/static/fonts/simfang.ttf");
        if (is == null) {
            throw new IOException("字体文件未找到");
        }
        byte[] fontBytes = toByteArray(is);
        BaseFont baseFont = BaseFont.createFont("simfang.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED, true, fontBytes, null);
        Font font = new Font(baseFont, 12);
        // 创建表格
        PdfPTable table = new PdfPTable(4);
        table.setWidthPercentage(100);
        // 在表格单元格中也应使用相同的字体
        table.addCell(new PdfPCell(new Phrase("用户名", font)));
        table.addCell(new PdfPCell(new Phrase("姓名", font)));
        table.addCell(new PdfPCell(new Phrase("邮箱", font)));
        table.addCell(new PdfPCell(new Phrase("手机号", font)));
        for (SysUser user : users) {
            table.addCell(new PdfPCell(new Phrase(user.getUserName(), font)));
            table.addCell(new PdfPCell(new Phrase(user.getNickName(), font)));
            table.addCell(new PdfPCell(new Phrase(user.getEmail(), font)));
            table.addCell(new PdfPCell(new Phrase(user.getPhonenumber(), font)));
        }
        document.add(table);
        document.close();
        return baos.toByteArray();
    }
    /**
     * 流转byte字节
     * @param is
     * @return
     * @throws IOException
     */
    private byte[] toByteArray(InputStream is) throws IOException {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        int nRead;
        byte[] data = new byte[16384];
        while ((nRead = is.read(data, 0, data.length)) != -1) {
            buffer.write(data, 0, nRead);
        }
        buffer.flush();
        return buffer.toByteArray();
    }
}