如何实现文档在线预览？aspose轻松解决
现状：
目前市场上ERP、MES、CRM等系统大部分都包含有文件预览。Web浏览器要实现文件预览的功能，一般都需要服务器传回pdf文件流，才能在页面实现预览功能。那么pdf以外的文件就必须得先转成pdf文件才能实现。以下以aspose实现文件转为pdf文件。
项目中引入aspose依赖：
<dependency>
<groupId>com.aspose</groupId>
<artifactId>aspose-words</artifactId>
<version>15.8.0</version>
</dependency>
<dependency>
<groupId>com.aspose</groupId>
<artifactId>aspose-cells</artifactId>
<version>8.5.2</version>
</dependency>
最好把jar包下载下来，放入本地maven库。
百度网盘链接 https://pan.baidu.com/s/10Rm2mic0Dam4EbOCLYK26g?pwd=s44e
提取码：s44e
license.xml放入项目中：
Springboot项目中结构如下图
<License>
<Data>
<Products>
<Product>Aspose.Total for Java</Product>
<Product>Aspose.Words for Java</Product>
</Products>
<EditionType>Enterprise</EditionType>
<SubscriptionExpiry>20991231</SubscriptionExpiry>
<LicenseExpiry>20991231</LicenseExpiry>
<SerialNumber>23dcc79f-44ec-4a23-be3a-03c1632404e9</SerialNumber>
</Data>
<Signature>0nRuwNEddXwLfXB7pw66G71MS93gW8mNzJ7vuh3Sf4VAEOBfpxtHLCotymv1PoeukxYe31K441Ivq0Pkvx1yZZG4O1KCv3Omdbs7uqzUB4xXHlOub4VsTODzDJ5MWHqlRCB1HHcGjlyT2sVGiovLt0Grvqw5+QXBuinoBY0suX0=</Signature>
</License>
封装工具类：
import com.alibaba.excel.EasyExcel; import com.aspose.cells.PdfSaveOptions; import com.aspose.cells.Workbook; import com.aspose.words.Document; import com.aspose.words.License; import com.aspose.words.SaveFormat; import lombok.extern.slf4j.Slf4j; import org.springframework.core.io.ClassPathResource; import org.springframework.stereotype.Component; import javax.servlet.http.HttpServletResponse; import java.io.*; import java.util.Map; @Slf4j @Component public class FileUtil { /** * 文件下载方法 * * @param filename 文件保存名 * @param filePath 文件下载路径 * @param res * @throws IOException */ public static void downloadFile(String filename, String filePath, HttpServletResponse res) throws IOException { // 发送给客户端的数据 OutputStream outputStream = res.getOutputStream(); byte[] buff = new byte[1024]; BufferedInputStream bis = null; // 读取filename bis = new BufferedInputStream(new FileInputStream(new File(filePath + filename))); int i = bis.read(buff); while (i != -1) { outputStream.write(buff, 0, buff.length); outputStream.flush(); i = bis.read(buff); } outputStream.close(); } public static void deleteFile(String filename, String filePath) { File file = new File(filePath + filename); if (file.exists()) {//文件是否存在 file.delete();//删除文件 } } /** * @Author WXK * @Description 返回预览pdf流 * @Date 2021/3/11 **/ public static void previewFile1(String filePath, HttpServletResponse res) throws IOException { // 发送给客户端的数据 OutputStream outputStream = res.getOutputStream(); try { byte[] buff = new byte[1024]; BufferedInputStream bis = null; // 读取filename bis = new BufferedInputStream(new FileInputStream(new File(filePath))); int i = bis.read(buff); while (i != -1) { outputStream.write(buff, 0, buff.length); outputStream.flush(); i = bis.read(buff); } } catch (Exception e) { e.printStackTrace(); } finally { outputStream.close(); } } /** * @Author WXK * @Description 删除转换生成的pdf文件 * @Date 2021/3/11 **/ public static void deleteFile1(String filePath) { File file = new File(filePath); if (file.exists()) {//文件是否存在 file.delete();//删除文件 } } public static boolean getLicense() { boolean result = false; try { InputStream is = Test.class.getClassLoader().getResourceAsStream("license.xml"); // License aposeLic = new License(); aposeLic.setLicense(is); result = true; } catch (Exception e) { e.printStackTrace(); } return result; } public static boolean getExcelLicense() { boolean result = false; try { InputStream is = Test.class.getClassLoader().getResourceAsStream("license.xml"); // com.aspose.cells.License license = new com.aspose.cells.License(); license.setLicense(is); result = true; } catch (Exception e) { e.printStackTrace(); } return result; } /** * @Author WXK * @Description word转 pdf * @Date 2021/3/12 **/ public static String doc2pdf(String fileName, String filePath) { if (!getLicense()) { // 验证License 若不验证则转化出的pdf文档会有水印产生 return null; } try { String oldFile = filePath + fileName; String newFile = oldFile.substring(0, oldFile.lastIndexOf("."))+".pdf"; File file = new File(newFile); //新建一个空白pdf文档 FileOutputStream os = new FileOutputStream(file); Document doc = new Document(oldFile); //Address是将要被转化的word文档 doc.save(os, SaveFormat.PDF);//全面支持DOC, DOCX, OOXML, RTF HTML, OpenDocument, PDF, EPUB, XPS, SWF 相互转换 log.info("转换成功"); //转化用时 return newFile; } catch (Exception e) { e.printStackTrace(); } return null; } /** * @Author WXK * @Description 上传文件时,word转pdf 保存在本地 * @Date 2021/3/29 **/ public static String doc2pdf(InputStream inputStream,String fileName, String filePath) { if (!getLicense()) { // 验证License 若不验证则转化出的pdf文档会有水印产生 return null; } try { String newFile = filePath + fileName; File file = new File(newFile); //新建一个空白pdf文档 FileOutputStream os = new FileOutputStream(file); Document doc = new Document(inputStream); //Address是将要被转化的word文档 doc.save(os, SaveFormat.PDF);//全面支持DOC, DOCX, OOXML, RTF HTML, OpenDocument, PDF, EPUB, XPS, SWF 相互转换 log.info("转换成功"); //转化用时 return newFile; } catch (Exception e) { e.printStackTrace(); } return null; } /** * @Author WXK * @Description excel转pdf * @Date 2021/3/22 **/ public static String excelToPdf(String fileName, String filePath) throws IOException{ if (!getExcelLicense()) { // 验证License 若不验证则转化出的pdf文档会有水印产生 return null; } FileOutputStream fileOS=null; try { String oldFile = filePath + fileName; String newFile = oldFile.substring(0, oldFile.lastIndexOf("."))+".pdf"; File pdfFile = new File(newFile);// 输出路径 /* Workbook wb = new Workbook(oldFile);// 原始excel路径 fileOS = new FileOutputStream(pdfFile); wb.save(fileOS, SaveFormat.PDF); fileOS.flush(); log.info("转换成功");*/ Workbook wb = new Workbook(oldFile);// 原始excel路径 fileOS = new FileOutputStream(newFile); PdfSaveOptions pdfSaveOptions = new PdfSaveOptions(); pdfSaveOptions.setOnePagePerSheet(true); int[] autoDrawSheets={3}; //当excel中对应的sheet页宽度太大时，在PDF中会拆断并分页。此处等比缩放。 autoDraw(wb,autoDrawSheets); int[] showSheets={0}; //隐藏workbook中不需要的sheet页。 printSheetPage(wb,showSheets); wb.save(fileOS, pdfSaveOptions); fileOS.flush(); fileOS.close(); log.info("完毕"); return newFile; } catch (Exception e) { e.printStackTrace(); }finally { fileOS.close(); } return null; } /** * @Author WXK * @Description 上传文件时 excel转pdf保存在本地 * @Date 2021/3/29 **/ public static String excelToPdf(InputStream inputStream, String fileName,String filePath) throws IOException{ if (!getExcelLicense()) { // 验证License 若不验证则转化出的pdf文档会有水印产生 return null; } FileOutputStream fileOS=null; try { String newFile = filePath + fileName; Workbook wb = new Workbook(inputStream);// 原始excel路径 fileOS = new FileOutputStream(newFile); PdfSaveOptions pdfSaveOptions = new PdfSaveOptions(); pdfSaveOptions.setOnePagePerSheet(true); int[] autoDrawSheets={3}; //当excel中对应的sheet页宽度太大时，在PDF中会拆断并分页。此处等比缩放。 autoDraw(wb,autoDrawSheets); int[] showSheets={0}; //隐藏workbook中不需要的sheet页。 printSheetPage(wb,showSheets); wb.save(fileOS, pdfSaveOptions); fileOS.flush(); fileOS.close(); log.info("完毕"); return newFile; } catch (Exception e) { e.printStackTrace(); }finally { fileOS.close(); } return null; } /** * 设置打印的sheet 自动拉伸比例 * @param wb * @param page 自动拉伸的页的sheet数组 */ public static void autoDraw(Workbook wb,int[] page){ if(null!=page&&page.length>0){ for (int i = 0; i < page.length; i++) { wb.getWorksheets().get(i).getHorizontalPageBreaks().clear(); wb.getWorksheets().get(i).getVerticalPageBreaks().clear(); } } } /** * 隐藏workbook中不需要的sheet页。 * @param wb * @param page 显示页的sheet数组 */ public static void printSheetPage(Workbook wb,int[] page){ for (int i= 1; i < wb.getWorksheets().getCount(); i++) { wb.getWorksheets().get(i).setVisible(false); } if(null==page||page.length==0){ wb.getWorksheets().get(0).setVisible(true); }else{ for (int i = 0; i < page.length; i++) { wb.getWorksheets().get(i).setVisible(true); } } } /** * @Author WXK * @Description 查看对应的.pdf文件是否存在 * @Date 2021/3/12 **/ public static boolean checkFileExist(String filePath) { File file = new File(filePath); if (file.exists()) {//文件是否存在 return true; } return false; } }
controller层：
import com.shuangjia.constant.Constant;
import com.shuangjia.model.PeDownloadLog;
import com.shuangjia.model.PeFile;
import com.shuangjia.model.ResultEntity;
import com.shuangjia.model.UserSession;
import com.shuangjia.util.FileUtil;
import com.shuangjia.web.pepd.feginService.PeFileService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.multipart.MultipartFile;
import javax.activation.MimetypesFileTypeMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.UUID;
public class PeFileController {
@Value("${upload.path}")
private String path;
@Value("${upload.picture.path}")
private String uploadPath;
@PostMapping("/previewFile")
@ApiOperation("返回文件流")
public void previewFile(@RequestBody PeFile po,HttpServletResponse response)throws IOException{
String fileName=po.getFileName();
String suffix = fileName.substring(fileName.lastIndexOf(".") + 1);
if("pdf".equalsIgnoreCase(suffix)){
String type = new MimetypesFileTypeMap().getContentType(fileName);
response.setHeader("Content-type",type);
String newFileName = new String(fileName.getBytes("utf-8"), "iso-8859-1");
// 设置扩展头，当Content-Type 的类型为要下载的类型时 , 这个信息头会告诉浏览器这个文件的名字和类型。
response.setHeader("Content-Disposition", "attachment;filename=" + newFileName);
FileUtil.downloadFile(fileName,path,response);
}
String filePath = path + fileName.substring(0,fileName.lastIndexOf(".")) + ".pdf";
if( FileUtil.checkFileExist(filePath)){
FileUtil.previewFile1(filePath,response);
}else {
String newFilePath=null;
if("XLSX".equalsIgnoreCase(suffix) || "XLS".equalsIgnoreCase(suffix)){
newFilePath=FileUtil.excelToPdf(fileName,path);
}else {
//DOC, DOCX, OOXML, RTF HTML, OpenDocument, PDF, EPUB, XPS, SWF
newFilePath = FileUtil.doc2pdf(fileName, path);
}
if(StringUtils.isNotBlank(newFilePath)){
FileUtil.previewFile1(newFilePath,response);
}
}
}
}
最后返回给前端页面的是一个pdf流
效果图：
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