使用pdfobject预览pdf文件

冷不防 2023-10-05 13:32 29阅读 0赞

1.页面代码，引入js文件，根据文件id加载pdf预览文件

2.后台根据文件id返回文件流展示pdf文件

（1）controller层，根据文件id查询文件存在在minio中的位置信息

@RequestMapping(value = { "/previewFileById" }, produces = { "text/html;charset=UTF-8" })
    	@ResponseBody
    	public void previewFileById(HttpServletRequest request, HttpServletResponse response) {
    		try {
    			response.setCharacterEncoding("UTF-8");
    			String id = request.getParameter("id");
    			ScoreFile scoreFile = scoreFileService.findById(id);
    			String fileDirectory = scoreFile.getFileDirectory();
    			String fileNameUuidPdf = scoreFile.getFileNewName();
    			String fileName = scoreFile.getFileName();
    			String fileNamePdf = fileName.substring(0, fileName.lastIndexOf(".")) + ".pdf"; // pdf文件名
    			String path = scoreFile.getFilePath() + fileNameUuidPdf;
    			FileUtils.previewfileById(fileDirectory, path, fileNamePdf, response); // 跟据存放在minio中目录得到转化好的PDF文件流
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}

（2）根据存放位置信息加载文件，返回文件流，写在fileutils工具类中

public static void previewfileById(String fileDirectory, String path, String fileNamePdf,HttpServletResponse response) {
    				InputStream in = null;
    		        OutputStream out = null;
    		        MinioClient minioClient = FileUtils.getInstance();
    		        try
    		        {
    		          in = minioClient.getObject(fileDirectory, path);
    		          int len = 0;
    		          byte[] buffer = new byte[1024];
    		          out = response.getOutputStream();
    		          response.reset();   
    		          String filename = getFileNameForISO8859(fileNamePdf);      //得到iso-8859-1编码的文件名
    		          response.addHeader("Content-Disposition","inline;filename="+filename);
    		          response.setContentType("application/pdf;charset=UTF-8");
    		          while ((len = in.read(buffer)) > 0) {
    		            out.write(buffer, 0, len);
    		          } 
    		        } catch (Exception e){
    		        	e.printStackTrace();
    		        } finally {
    		          if (in != null) {
    		            try
    		            {
    		              in.close();
    		            }
    		            catch (Exception e)
    		            {
    		              throw new RuntimeException(e);
    		            }
    		          }
    		          if (out != null) {
    		            try {
    						out.close();
    					} catch (IOException e) {
    						e.printStackTrace();
    					}
    		          }
    		        }
    				
    			}
    			
    			/**
    			 * @Description 得到iso-8859-1编码的文件名
    			 * @author [zhanglizeng] 
    			 * @throws UnsupportedEncodingException 
    			 * @createDate 2018年9月28日 下午6:46:41
    			 */
    			private static String getFileNameForISO8859(String fileNamePdf) throws UnsupportedEncodingException {
    				Pattern pattern = Pattern.compile("[\u4e00-\u9fa5]");  //匹配中文
    				if (fileNamePdf != null) {
    				    Matcher aMatcher = pattern.matcher(fileNamePdf);
    				    if(!aMatcher.find()) {
    				    	fileNamePdf = "下载-"+fileNamePdf;
    				    }
    				    return new String(fileNamePdf.getBytes(),"iso-8859-1");
    				}
    				return "文件名为空";
    			}
    
            //创建minio的链接
            public static MinioClient getInstance() {
                if (minioClient == null) {  
                synchronized (FileUtils.class) {  
                    if (minioClient == null) {  
                    	try {
                    		//new FileUtils(); 
                    		minioClient = new             MinioClient(minioUrl,minioUsername,minioPassword);
    					} catch (Exception e) {
    						e.printStackTrace();
    					}
                    }  
                   }  
                }  
                return minioClient;  
            }