springMVC-文件操作

文件下载

@RequestMapping("/testDown") 
public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException { 
//获取ServletContext对象 
ServletContext servletContext = session.getServletContext(); 
//获取服务器中文件的真实路径 
String realPath = servletContext.getRealPath("/static/img/1.jpg"); 
//创建输入流 InputStream is = new FileInputStream(realPath); 
//创建字节数组 
byte[] bytes = new byte[is.available()]; 
//将流读到字节数组中
 is.read(bytes); 
//创建HttpHeaders对象设置响应头信息 
MultiValueMap<String, String> headers = new HttpHeaders();
 //设置要下载方式以及下载文件的名字 
headers.add("Content-Disposition", "attachment;filename=1.jpg"); 
//设置响应状态码 
HttpStatus statusCode = HttpStatus.OK; 
//创建ResponseEntity对象
 ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode); 
//关闭输入流 
is.close(); 
return responseEntity; 
}

文件上传

文件上传要求form表单的请求方式必须为post，并且添加属性enctype="multipart/form-data" SpringMVC中将上传的文件封装到MultipartFile对象中，通过此对象可以获取文件相关信息

1.添加依赖

<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -- >
<dependency> 
<groupId>commons-fileupload</groupId> 
<artifactId>commons-fileupload</artifactId> 
<version>1.3.1</version> 
</dependency>

2.Springmvc配置文件

<!--必须通过文件解析器的解析才能将文件转换为MultipartFile对象--> 
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> 
</bean>

3.控制器方法

@RequestMapping("/testUp") 
public String testUp(MultipartFile photo, HttpSession session) throws IOException { 
//获取上传的文件的文件名 
String fileName = photo.getOriginalFilename(); 
//处理文件重名问题 
String hzName = fileName.substring(fileName.lastIndexOf(".")); fileName = UUID.randomUUID().toString() + hzName; 
//获取服务器中photo目录的路径 
ServletContext servletContext = session.getServletContext(); 
String photoPath = servletContext.getRealPath("photo"); 
File file = new File(photoPath);
 if(!file.exists()){
 file.mkdir(); 
}
String finalPath = photoPath + File.separator + fileName; 
//实现上传功能
 photo.transferTo(new File(finalPath)); 
return "success"; 
}