HSSFWorkbook workbook = new HSSFWorkbook();
//业务逻辑，给HSSFWorkbook添加数据
//end
ByteArrayOutputStream bos=new ByteArrayOutputStream();
workbook.write(bos);
byte[] barray=bos.toByteArray();
//is第一转
InputStream is=new ByteArrayInputStream(barray);
//需要导包
//如果是spring boot把下面的导入pom.xml
MultipartFile multipartFile = new MockMultipartFile("文件名","文件名","文件名",is);
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.1.6.RELEASE</version>
<scope>compile</scope>
</dependency>
