本文实例为大家分享了java实现文件上传下载的具体代码，供大家参考，具体内容如下
1.上传单个文件
Controller控制层
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import java.io.File;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Controller;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.multipart.MultipartFile;import org.springframework.web.servlet.mvc.support.RedirectAttributes;@Controller@RequestMapping("testup")public class UploadController { private static Logger LG= LoggerFactory.getLogger(UploadController.class); /** * 9.①单个文件上传 * @param file * @param redirectAttributes * @return */ @RequestMapping(value="/upload",method=RequestMethod.POST,consumes="multipart/form-data") public String uploadFile(@RequestParam MultipartFile file,RedirectAttributes redirectAttributes){ if(file.isEmpty()){ redirectAttributes.addFlashAttribute("message", "Plse select file"); return "redirect:/test/index"; } try { String fileName=file.getOriginalFilename(); /*上传文件存储位置*/ String destFileName="D:\\whupload"+File.separator+fileName; File destFile=new File(destFileName); file.transferTo(destFile); //文件上传成功显示 //redirectAttributes.addAttribute("message","upload file success."); redirectAttributes.addFlashAttribute("message", "upload file success."); } catch (Exception e) { //文件上传失败显示 redirectAttributes.addFlashAttribute("message", "upload file fail"); LG.debug(e.getMessage()); } return "redirect:/test/index"; }} |
前端页面源码
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<p>上传文件，使用multipart/form-data类型</p> <form action="/testup/upload" method="post" enctype="multipart/form-data"> <input type="file" name="file"> <button type="submit">上传</button></form> |
2.上传多个文件
Controller控制层
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import java.io.File;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Controller;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.multipart.MultipartFile;import org.springframework.web.servlet.mvc.support.RedirectAttributes;@Controller@RequestMapping("testup")public class UploadController { private static Logger LG= LoggerFactory.getLogger(UploadController.class); /** * 9.②多个文件上传 */ @RequestMapping(value="/uploadBatchFile",method=RequestMethod.POST,consumes="multipart/form-data") public String uploadBatchFile(@RequestParam MultipartFile[] files,RedirectAttributes redirectAttributes){ boolean isEmpty=true; try { for (MultipartFile multipartFile : files) { if(multipartFile.isEmpty()){ continue; } String fileName=multipartFile.getOriginalFilename(); String destFileName="D:\\whupload"+File.separator+fileName; File destFile=new File(destFileName); multipartFile.transferTo(destFile); isEmpty=false; } //int i=1/0; //localhost:8086/test/index?message=upload file success //redirectAttributes.addAttribute("message","upload file success."); } catch (Exception e) { // TODO Auto-generated catch block redirectAttributes.addFlashAttribute("message", "upload file fail"); LG.debug(e.getMessage()); return "redirect:/test/index"; } if(isEmpty){ redirectAttributes.addFlashAttribute("message", "Plse select file"); }else{ redirectAttributes.addFlashAttribute("message", "upload file success."); } return "redirect:/test/index"; } } |
前端页面源码
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<form action="/testup/uploadBatchFile" method="post" enctype="multipart/form-data"> <input type="file" name="files"> <input type="file" name="files"> <button type="submit">上传</button></form> |
3.下载文件
Controller控制器
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import java.io.File;import java.net.MalformedURLException;import java.nio.file.Paths;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.core.io.Resource;import org.springframework.core.io.UrlResource;import org.springframework.http.HttpHeaders;import org.springframework.http.ResponseEntity;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.ResponseBody;@Controller@RequestMapping("testup")public class UploadController { private static Logger LG= LoggerFactory.getLogger(UploadController.class); /** * 10.下载文件 */ @RequestMapping("/download") @ResponseBody public ResponseEntity<Resource> downloadFile(@RequestParam String fileName){ try { Resource resource=new UrlResource( //拼接下载的文件的原路径 Paths.get("D:/whupload"+File.separator+fileName).toUri()); if(resource.exists() && resource.isReadable()){ return ResponseEntity.ok() .header(HttpHeaders.CONTENT_TYPE, "application/octet-stream") .header(HttpHeaders.CONTENT_DISPOSITION,"attachment;filename=\""+ resource.getFilename()+"\"").body(resource); } } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); LG.debug(e.getMessage()); } return null; }} |
前端页面源码
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<p>下载文件，这里设置默认下载文件为Demo.txt,fileName是下载文件名</p><a href="/testup/download?fileName=Demo.txt" rel="external nofollow" >download file</a> |
运行效果
最后，需要注意的是，文件上传有默认的大小限制
在配置文件中加入，即可消除限制
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spring.servlet.multipart.max-file-size=-1spring.servlet.multipart.max-request-size=-1 |
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/wh456413/article/details/107302180
