一、pom

        <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>

二、解析器

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10485760"></property>
</bean>

三、控制器

    @RequestMapping("/addbook")
    public String addBook(@RequestParam("pics") MultipartFile file, HttpServletRequest request, Books book) throws IOException {
        //上传路径配置
        String filePath = request.getServletContext().getRealPath("");
        //获取原始图片的扩展名
        String originalFilename = file.getOriginalFilename();
        //新的文件名字，使用uuid随机生成数+原始图片名字，这样不会重复
        String newFileName = UUID.randomUUID()+originalFilename;
        System.out.println(newFileName);
        //封装上传文件位置的全路径，就是硬盘路径+文件名
        File targetFile = new File(filePath,newFileName);
        //把本地文件上传到已经封装好的文件位置的全路径就是上面的targetFile
        file.transferTo(targetFile);
        book.setPic(newFileName);

        bookService.addBook(book);
        return "redirect:/book/selectbookforpage";
    }