Java Spring MVC upload and download file configuration and controller method detailed explanation

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<!--配置下载返回类型-->
<bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<!--配置编码方式-->
<property name="supportedMediaTypes" value="application/json; charset=UTF-8" />
</bean>
</list>
</property>
</bean>

@RequestMapping("/file/{name.rp}")
public ResponseEntity<byte[]> fileDownLoad(@PathVariable("name.rp")String name, HttpServletRequest request,HttpServletResponse response) {
// @PathVariable String name,
// @RequestParam("name")String name,
// System.out.println("<name>"+name);
// System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
ResponseEntity<byte[]> re = null;
try {
/**
* css,js,json,gif,png,bmp,jpg,ico,doc,docx,xls,xlsx,txt,swf,pdf
* **/
//下载防止静态加载干扰
Feelutile f=new Feelutile();
name=f.getfileformat(name);
String pathString="C:\\tempDirectory\\"+name;
File file=new File(pathString);
HttpHeaders headers=new HttpHeaders();
//String filename=URLEncoder.encode(name, "UTF-8");//为了解决中文名称乱码问题
String filename=new String(name.getBytes("utf-8"),"utf-8");
byte[] by=FileUtils.readFileToByteArray(file);
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
//URLEncoder.encode(filename, "UTF-8")
headers.setContentDispositionFormData("attachment",filename);
headers.setContentLength(by.length);
re=new ResponseEntity<byte[]>(by, headers, HttpStatus.CREATED);
} catch (Exception e) {
e.printStackTrace();
try {
request.getRequestDispatcher("/error/404.jsp").forward(request, response);
} catch (ServletException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
return re;
}

<!--4.文件上传 配置 file upload -->
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding">
<value>UTF-8</value>
</property>
<property name="maxUploadSize">
<value>1048576000</value>
</property>
<property name="maxInMemorySize">
<value>40960</value>
</property>
</bean>

@RequestMapping(value="/upload", method = RequestMethod.POST)
@ResponseBody
public Json upload(Doc doc, @RequestParam("uploadFile") CommonsMultipartFile file) {
Json j = new Json();
try {
String realpath = this.servletContext.getRealPath("/upload");
String uploadFileFileName = file.getOriginalFilename();
String uploadFileFileNameWithoutSpace = uploadFileFileName.replaceAll(" ", "");
String fileType = uploadFileFileNameWithoutSpace.substring(uploadFileFileNameWithoutSpace.lastIndexOf("."));
File targetFile = new File(realpath+File.separator, uploadFileFileNameWithoutSpace);
if (targetFile.exists()) {
targetFile.delete();
}
file.getFileItem().write(targetFile);
docService.upload(doc,uploadFileFileNameWithoutSpace);
j.setSuccess(true);
j.setMsg("Upload manual successfully");
}catch (Exception e) {
logger.error(ExceptionUtil.getExceptionMessage(e));
j.setMsg("Upload manual unsuccessfully");
}
return j;
}