目录
前言
本文实现 Springboot 整合 itext 实现PDF文件合并,图片转PDF拼接。
一、引用依赖
xml
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itext7-core</artifactId>
<version>8.0.5</version>
<type>pom</type>
</dependency>
二、使用步骤
1.Controller
代码如下(示例):
java
import com.ruoyi.tools.service.IPdfHandlerService;
import lombok.RequiredArgsConstructor;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.util.List;
@RestController
@RequiredArgsConstructor
@RequestMapping("/pdf")
public class PdfHandlerController {
private final IPdfHandlerService pdfHandlerService;
@PostMapping(value = "/generateFromFiles", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public void uploadFiles(@RequestPart("files") List<MultipartFile> files, HttpServletResponse response) throws Exception {
byte[] pdfBytes = pdfHandlerService.generatePdfFromFiles(files);
response.setContentType("application/pdf");
response.setContentLength(pdfBytes.length);
//把字节数组写入输出流中
response.getOutputStream().write(pdfBytes);
}
2.Service接口
java
import org.springframework.web.multipart.MultipartFile;
import java.util.List;
public interface IPdfHandlerService {
byte[] generatePdfFromFiles(List<MultipartFile> files);
}
3.实现类
java
import com.itextpdf.io.image.ImageDataFactory;
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.PdfReader;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Image;
import com.itextpdf.layout.element.Paragraph;
import com.ruoyi.tools.service.IPdfHandlerService;
import lombok.SneakyThrows;
import org.apache.commons.io.FilenameUtils;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.List;
@Service
public class PdfHandlerServiceImpl implements IPdfHandlerService {
@SneakyThrows
public byte[] generatePdfFromFiles(List<MultipartFile> files) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfWriter writer = new PdfWriter(baos);
PdfDocument pdfDoc = new PdfDocument(writer);
Document document = new Document(pdfDoc);
for (MultipartFile file : files) {
if (isPdf(file)) {
PdfDocument sourcePdf = new PdfDocument(new PdfReader(file.getInputStream()));
int n = sourcePdf.getNumberOfPages();
for (int i = 1; i <= n; i++) {
PdfPage page = sourcePdf.getPage(i);
PdfFormXObject pageCopy = page.copyAsFormXObject(pdfDoc);
Rectangle pageSize = page.getPageSize();
PdfPage newPage = pdfDoc.addNewPage();
newPage.setMediaBox(pageSize);
new PdfCanvas(newPage).addXObjectAt(pageCopy, 0, 0);
newPage.setRotation(page.getRotation());
}
sourcePdf.close();
continue;
}
if (isImage(file)) {
// 创建一个新的 A4 页面
PdfPage newPage = pdfDoc.addNewPage(PageSize.A4);
Image img = new Image(ImageDataFactory.create(file.getBytes()));
// 设置图片大小以适应 A4 页面
img.scaleToFit(PageSize.A4.getWidth(), PageSize.A4.getHeight());
// 获取当前页面编号
int pageNumber = pdfDoc.getNumberOfPages();
// 设置图片位置为页面中心
img.setFixedPosition(pageNumber,
(PageSize.A4.getWidth() - img.getImageScaledWidth()) / 2,
(PageSize.A4.getHeight() - img.getImageScaledHeight()) / 2);
// 添加图片到文档
document.add(img);
continue;
}
//可以删掉此提示
document.add(new Paragraph(file.getOriginalFilename() + "仅支持PDF和图片的拼接"));
}
document.close();
return baos.toByteArray();
}
@SneakyThrows
private boolean isPdf(MultipartFile file) {
String contentType = file.getContentType();
String extension = FilenameUtils.getExtension(file.getOriginalFilename());
if (contentType != null && contentType.equals("application/pdf")) {
return true;
}
if ("pdf".equalsIgnoreCase(extension)) {
byte[] fileHeader = new byte[4];
try (ByteArrayInputStream bis = new ByteArrayInputStream(file.getBytes())) {
int bytesRead = bis.read(fileHeader);
if (bytesRead != fileHeader.length) {
return false;
}
}
return new String(fileHeader).startsWith("%PDF");
}
return false;
}
@SneakyThrows
private boolean isImage(MultipartFile file) {
String contentType = file.getContentType();
String extension = FilenameUtils.getExtension(file.getOriginalFilename());
if (contentType != null && contentType.startsWith("image")) {
return true;
}
if (extension != null) {
switch (extension.toLowerCase()) {
case "jpg":
case "jpeg":
case "png":
case "gif":
case "bmp":
return true;
default:
return false;
}
}
return false;
}
}