首先描述一下问题,spring boot 使用的是内嵌的tomcat, 所以不清楚文件上传到哪里去了, 而且spring boot 把静态的文件全部在启动的时候都会加载到classpath的目录下的,所以上传的文件不知相对于应用目录在哪,也不知怎么写访问路径合适,对于新手的自己真的一头雾水。
后面想起了官方的例子,没想到一开始被自己找到的官方例子,后面太依赖百度谷歌了,结果发现只有官方的例子能帮上忙,而且帮上大忙,直接上密码的代码
package hello; import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo; import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodon; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Paths; import java.util.stream.Collectors; import javax.servlet.http.HttpServletRequest; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.core.io.ResourceLoader; import org.springframework.http.ResponseEntity; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.multipart.multipartfile; import org.springframework.web.servlet.mvc.support.RedirectAttributes; @Controller public class FileUploadController { private static final Logger log = LoggerFactory.getLogger(FileUploadController.class); public static final String ROOT = "upload-dir"; private final ResourceLoader resourceLoader; @Autowired public FileUploadController(ResourceLoader resourceLoader) { this.resourceLoader = resourceLoader; } @RequestMapping(method = RequestMethod.GET,value = "/") public String provideUploadInfo(Model model) throws IOException { model.addAttribute("files",Files.walk(Paths.get(ROOT)) .filter(path -> !path.equals(Paths.get(ROOT))) .map(path -> Paths.get(ROOT).relativize(path)) .map(path -> linkTo(methodon(FileUploadController.class).getFile(path.toString())).withRel(path.toString())) .collect(Collectors.toList())); return "uploadForm"; } //显示图片的方法关键 匹配路径像 localhost:8080/b7c76eb3-5a67-4d41-ae5c-1642af3f8746.png @RequestMapping(method = RequestMethod.GET,value = "/{filename:.+}") @ResponseBody public ResponseEntity<?> getFile(@PathVariable String filename) { try { return ResponseEntity.ok(resourceLoader.getResource("file:" + Paths.get(ROOT,filename).toString())); } catch (Exception e) { return ResponseEntity.notFound().build(); } } <strong>//上传的方法</strong> @RequestMapping(method = RequestMethod.POST,value = "/") public String handleFileUpload(@RequestParam("file") multipartfile file,RedirectAttributes redirectAttributes,HttpServletRequest request) { System.out.println(request.getParameter("member")); if (!file.isEmpty()) { try { Files.copy(file.getInputStream(),Paths.get(ROOT,file.getoriginalFilename())); redirectAttributes.addFlashAttribute("message","You successfully uploaded " + file.getoriginalFilename() + "!"); } catch (IOException|RuntimeException e) { redirectAttributes.addFlashAttribute("message","Failued to upload " + file.getoriginalFilename() + " => " + e.getMessage()); } } else { redirectAttributes.addFlashAttribute("message","Failed to upload " + file.getoriginalFilename() + " because it was empty"); } return "redirect:/"; } }
看完上面的代码可以理解到spring boot 的存取文件思路了,存的时候的路径为
Paths.get(ROOT,filename).toString()))
这个路径会在本地的工程根目录上创建,不应用部署里的目录,所以一般的访问http访问不可能 ,所以它提供了ResourceLoader,利于这个类可以加载非应用目录的里文件然后返回
如果大家对spring boot不是很了解,大家可以参考下面两篇文章。
以上所述是小编给大家介绍的spring boot 图片上传与显示功能实例详解,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对编程小技巧网站的支持!
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