Spring Upload file 报错FileNotFoundException
环境：
Springboot 2.0.4 JDK8 内嵌 Apache Tomcat/8.5.32表单，enctype 和 input 的type=file 即可，例子使用单文件上传
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< form enctype = "multipart/form-data" method = "POST" action = "/file/fileUpload" > 图片< input type = "file" name = "file" /> < input type = "submit" value = "上传" /> </ form > |
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@Controller @RequestMapping ( "/file" ) public class UploadFileController { @Value ( "${file.upload.path}" ) private String path = "upload/" ;
@RequestMapping (value = "fileUpload" , method = RequestMethod.POST) @ResponseBody public String fileUpload( @RequestParam ( "file" ) MultipartFile file) { if (file.isEmpty()) { return "false" ; } String fileName = file.getOriginalFilename(); File dest = new File(path + "/" + fileName); if (!dest.getParentFile().exists()) { dest.getParentFile().mkdirs(); } try { file.transferTo(dest); // 保存文件 return "true" ; } catch (Exception e) { e.printStackTrace(); return "false" ; } } } |
运行在保存文件 file.transferTo(dest) 报错
问题
dest 是相对路径，指向 upload/doc20170816162034_001.jpg
file.transferTo 方法调用时，判断如果是相对路径，则使用temp目录，为父目录
因此，实际保存位置为 C:\Users\xxxx\AppData\Local\Temp\tomcat.372873030384525225.8080\work\Tomcat\localhost\ROOT\upload\doc20170816162034_001.jpg
一则，位置不对，二则没有父目录存在，因此产生上述错误。
解决办法
transferTo 传入参数 定义为绝对路径
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@Controller @RequestMapping ( "/file" ) public class UploadFileController { @Value ( "${file.upload.path}" ) private String path = "upload/" ;
@RequestMapping (value = "fileUpload" , method = RequestMethod.POST) @ResponseBody public String fileUpload( @RequestParam ( "file" ) MultipartFile file) { if (file.isEmpty()) { return "false" ; } String fileName = file.getOriginalFilename(); File dest = new File( new File(path).getAbsolutePath()+ "/" + fileName); if (!dest.getParentFile().exists()) { dest.getParentFile().mkdirs(); } try { file.transferTo(dest); // 保存文件 return "true" ; } catch (Exception e) { e.printStackTrace(); return "false" ; } } } |
另外也可以 file.getBytes() 获得字节数组，OutputStream.write(byte[] bytes)自己写到输出流中。
补充方法
application.properties 中增加配置项
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spring.servlet.multipart.location= # Intermediate location of uploaded files. |
关于上传文件的访问
1、增加一个自定义的ResourceHandler把目录公布出去
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// 写一个Java Config @Configuration public class webMvcConfig implements org.springframework.web.servlet.config.annotation.WebMvcConfigurer{ // 定义在application.properties @Value ( "${file.upload.path}" ) private String path = "upload/" ; public void addResourceHandlers(ResourceHandlerRegistry registry) { String p = new File(path).getAbsolutePath() + File.separator; //取得在服务器中的绝对路径 System.out.println( "Mapping /upload/** from " + p); registry.addResourceHandler( "/upload/**" ) // 外部访问地址 .addResourceLocations( "file:" + p) // springboot需要增加file协议前缀 .setCacheControl(CacheControl.maxAge( 30 , TimeUnit.MINUTES)); // 设置浏览器缓存30分钟 } } |
application.properties 中 file.upload.path=upload/
实际存储目录
D:/upload/2019/03081625111.jpg
访问地址（假设应用发布在http://HdhCmsTesta测试数据/）
http://HdhCmsTesta测试数据/upload/2019/03081625111.jpg
2、在Controller中增加一个RequestMapping，把文件输出到输出流中
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@RestController @RequestMapping ( "/file" ) public class UploadFileController { @Autowired protected HttpServletRequest request; @Autowired protected HttpServletResponse response; @Autowired protected ConversionService conversionService;
@Value ( "${file.upload.path}" ) private String path = "upload/" ;
@RequestMapping (value= "/view" , method = RequestMethod.GET) public Object view( @RequestParam ( "id" ) Integer id){ // 通常上传的文件会有一个数据表来存储，这里返回的id是记录id UploadFile file = conversionService.convert(id, UploadFile. class ); // 这步也可以写在请求参数中 if (file== null ){ throw new RuntimeException( "没有文件" ); }
File source= new File( new File(path).getAbsolutePath()+ "/" + file.getPath()); response.setContentType(contentType);
try { FileCopyUtils.copy( new FileInputStream(source), response.getOutputStream()); } catch (Exception e) { e.printStackTrace(); } return null ; } } |
MultipartFile.transferTo(dest) 报找不到文件
今天使用transferTo这个方法进行上传文件的使用发现了一些路径的一些问题，查找了一下记录问题所在
前端上传网页，使用的是单文件上传的方式
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<!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" > < title >Title</ title > < meta http-equiv = "Content-Type" content = "text/html; charset=utf-8" /> </ head > < body > < form enctype = "multipart/form-data" method = "post" action = "/upload" > 文件：< input type = "file" name = "head_img" > 姓名：< input type = "text" name = "name" > < input type = "submit" value = "上传" > </ form > </ body > </ html > |
后台网页
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@Controller @RequestMapping ( "/file" ) public class UploadFileController { @Value ( "${file.upload.path}" ) private String path = "upload/" ; @RequestMapping (value = "fileUpload" , method = RequestMethod.POST) @ResponseBody public String fileUpload( @RequestParam ( "file" ) MultipartFile file) { if (file.isEmpty()) { return "false" ; } String fileName = file.getOriginalFilename(); File dest = new File(path + "/" + fileName); if (!dest.getParentFile().exists()) { dest.getParentFile().mkdirs(); } try { file.transferTo(dest); // 保存文件 return "true" ; } catch (Exception e) { e.printStackTrace(); return "false" ; } } } |
这个确实存在一些问题
路径是不对的
dest 是相对路径，指向 upload/doc20170816162034_001.jpg
file.transferTo 方法调用时，判断如果是相对路径，则使用temp目录，为父目录
因此，实际保存位置为 C:\Users\xxxx\AppData\Local\Temp\tomcat.372873030384525225.8080\work\Tomcat\localhost\ROOT\upload\doc20170816162034_001.jpg
所以改为：
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@Controller @RequestMapping ( "/file" ) public class UploadFileController { @Value ( "${file.upload.path}" ) private String path = "upload/" ; @RequestMapping (value = "fileUpload" , method = RequestMethod.POST) @ResponseBody public String fileUpload( @RequestParam ( "file" ) MultipartFile file) { if (file.isEmpty()) { return "false" ; } String fileName = file.getOriginalFilename(); File dest = new File( new File(path).getAbsolutePath()+ "/" + fileName); if (!dest.getParentFile().exists()) { dest.getParentFile().mkdirs(); } try { file.transferTo(dest); // 保存文件 return "true" ; } catch (Exception e) { e.printStackTrace(); return "false" ; } } } |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
原文链接：https://blog.csdn.net/dany_zj_cn/article/details/82019253
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