spring boot 项目打成jar包后读取文件问题

java.io.FileNotFoundException: class path resource [xxx.xls]
cannot be resolved to absolute file path because it does not reside in the file system: jar:file:/D:/新建文件夹/xxx.jar!/BOOT-INF/classes!/export/xxx.xls
at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:217)

在war包运行情况下是没问题的，路径其实是对的，spring是不允许直接访问jar包内的文件的，所以会报错，然后改写下读取文件的方式

• 精简的老代码方式

    ClassPathResource resource = new ClassPathResource("XXX.xls");
    File file = resource.getFile();
  

• 修改后的精简代码

    ClassPathResource resource = new ClassPathResource("application.yml");
    InputStream inputStream = resource.getInputStream();
  

• 笔者老代码

       public String generateExcel(String sourceFileName, String destFileName, Map<String, Object> params) throws Exception{
            XLSTransformer transformer = new XLSTransformer();
    
    //        URL url = this.getClass().getClassLoader().getResource("");
    //
    //        assert url != null;
            ClassPathResource resource = new ClassPathResource(EXPORT_RESOURCE_PATH + sourceFileName);
    
            transformer.transformXLS( resource.getFile().getPath(), params, TMP_DIR + destFileName);
            return TMP_DIR + destFileName;
        }
  

• 笔者新代码

       public String generateExcel(String sourceFileName, String destFileName, Map<String, Object> params) throws Exception{
    //        XLSTransformer transformer = new XLSTransformer();
    
    //        URL url = this.getClass().getClassLoader().getResource("");
    //
    //        assert url != null;
            ClassPathResource resource = new ClassPathResource(EXPORT_RESOURCE_PATH + sourceFileName);
    
            InputStream inputStream = resource.getInputStream();
    
    
    //        transformer.transformXLS( resource.getFile().getPath(), params, TMP_DIR + destFileName);
            transformXLS4Jar( inputStream, params, TMP_DIR + destFileName);
            return TMP_DIR + destFileName;
        }
  
      public  void transformXLS4Jar(InputStream is, Map beanParams, String destFilePath) throws ParsePropertyException, IOException, InvalidFormatException {
        XLSTransformer xlsTransformer = new XLSTransformer();
        org.apache.poi.ss.usermodel.Workbook workbook = xlsTransformer.transformXLS(is, beanParams);
        OutputStream os = new BufferedOutputStream(new FileOutputStream(destFilePath));
        workbook.write(os);
        is.close();
        os.flush();
        os.close();
    }