SpringBoot实现文件/图片的上传与下载

• 导入依赖（pom.xml）

　　　　<!-- 上传下载需要设计到的jar包 --><dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>2.6</version></dependency><dependency><groupId>commons-fileupload</groupId><artifactId>commons-fileupload</artifactId><version>1.3.3</version></dependency><!--servlet-api导入高版本的--><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>4.0.1</version></dependency><!-- 图片处理类 --><dependency><groupId>net.coobird</groupId><artifactId>thumbnailator</artifactId><version>0.4.8</version></dependency>

• 全局配置 application.properties

# 上传文件大小spring.servlet.multipart.max-file-size=5MBspring.servlet.multipart.max-request-size=5MB

• 创建 WebMvcConfig配置类静态资源映射

@Configurationpublic class WebMvcConfig implements WebMvcConfigurer {@Overridepublic void addResourceHandlers(ResourceHandlerRegistry registry) {ApplicationHome h = new ApplicationHome(getClass());File jarF = h.getSource();String dirPath = jarF.getParentFile().toString()+\"/upload/\";String os = System.getProperty(\"os.name\");if (os.toLowerCase().startsWith(\"win\")) {  //如果是Windows系统registry.addResourceHandler(\"/upload/**\").addResourceLocations(\"file:\"+dirPath);} else {registry.addResourceHandler(\"/upload/**\").addResourceLocations(\"file:\"+dirPath);}}}

• 文件或图片上传

• 控制层

// 上传文件@ResponseBody@RequestMapping(\"/upload\")public String fileUpload(@RequestParam(\"files\") MultipartFile files) throws IOException {//        // win系统 上传路径保存设置//        // 获取项目路径//        File projectPath = new File(ResourceUtils.getURL(\"classpath:\").getPath());//        // 绝对路径=项目路径+自定义路径//        File pathFile = new File(projectPath.getAbsolutePath(), \"static/upload/\");//        if (!pathFile.exists()) {//            pathFile.mkdirs();//        }//        //上传文件地址//        UUID uuid = UUID.randomUUID();//        File serverFile = new File(pathFile, uuid + \"_\" + files.getOriginalFilename());//        files.transferTo(serverFile);////        String imgPath = (\"/upload/\" + uuid + \"_\" + files.getOriginalFilename()).replace(\"\\\\\", \"/\");////        return imgPath;// Linux服务器  上传路径保存设置// 项目路径  /home/www/File pathFile = new File(\"/home/www/upload/\");if (!pathFile.exists()) {pathFile.mkdirs();}//上传文件地址UUID uuid = UUID.randomUUID();File serverFile = new File(pathFile, uuid + \"_\" + files.getOriginalFilename());files.transferTo(serverFile);String imgPath = (\"/upload/\" + uuid + \"_\" + files.getOriginalFilename()).replace(\"\\\\\", \"/\");return imgPath;}

• HTML页面 Ajax 无刷新上传

<form action=\"\" class=\"layui-form\" enctype=\"multipart/form-data\" method=\"post\">　　<input type=\"hidden\" name=\"blogImg\" id=\"imgPath\" value=\"\">　　<div class=\"form-group\">　　　　<label>图片上传</label>　　　　<input type=\'file\' style=\'margin: 5px;\' name=\'files\' required><br>　　　　<button type=\"button\" class=\"layui-btn\" id=\"img_upload\">上传图片</button>　　</div>　　<input type=\"submit\"></form>

• JS

//普通图片上传$(\'#img_upload\').click(function () {var formData = new FormData();//获取选择的文件$.each($(\'input[name=\"files\"]\'),function (index,item) {formData.append(\"files\",item.files[0])});//发送异步请求$.ajax({method:\'post\',url: \'[[@{/user/upload}]]\', // 文件上传接口data:formData,processData: false,contentType:false,success:function (data) {//成功返回触发的方法$(\'#imgPath\').val(data);alert(\"上传成功\");},//请求失败触发的方法error:function () {alert(\"上传失败\");}});});

• 文件或图片下载

• 控制层

@RequestMapping(value=\"/download\")public String downloads(HttpServletResponse response ,HttpServletRequest request) throws Exception{//要下载的图片地址String  path = request.getServletContext().getRealPath(\"/upload\");String  fileName = \"基础语法.jpg\";//1、设置response 响应头response.reset(); //设置页面不缓存,清空bufferresponse.setCharacterEncoding(\"UTF-8\"); //字符编码response.setContentType(\"multipart/form-data\"); //二进制传输数据//设置响应头response.setHeader(\"Content-Disposition\",\"attachment;fileName=\"+URLEncoder.encode(fileName, \"UTF-8\"));File file = new File(path,fileName);//2、 读取文件--输入流InputStream input=new FileInputStream(file);//3、 写出文件--输出流OutputStream out = response.getOutputStream();byte[] buff =new byte[1024];int index=0;//4、执行 写出操作while((index= input.read(buff))!= -1){out.write(buff, 0, index);out.flush();}out.close();input.close();return null;}

• HTML页面

<a href=\"/download\">点击下载</a>

参考资料：狂神说SpringMVC：文件上传下载