SpringMVC图片的上传和下载功能

@Controller
@RequestMapping("/upload")
public class UploadController {

    @RequestMapping(value = "/image", method = RequestMethod.POST)
    @ResponseBody
    public String uploadImage(@RequestParam("file") MultipartFile file) {
        String fileName = file.getOriginalFilename();
        String path = "D:/uploads/" + fileName;
        try {
            File dest = new File(path);
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();
            }
            file.transferTo(dest);
            return "success";
        } catch (Exception e) {
            e.printStackTrace();
            return "error";
        }
    }
}

@Controller
@RequestMapping("/download")
public class DownloadController {

    @RequestMapping(value = "/image/{id}", method = RequestMethod.GET)
    public ResponseEntity<byte[]> downloadImage(@PathVariable("id") int id) {
        Image image = imageService.getImageById(id);
        String fileName = image.getName();
        String path = "D:/uploads/" + fileName;
        try {
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
            headers.setContentDispositionFORMData("attachment", fileName);
            File file = new File(path);
            return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, httpstatus.CREATED);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

<!-- 文件上传配置 -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="10485760" />
</bean>

<!-- 文件下载配置 -->
<mvc:resources mapping="/download/**" location="file:/D:/uploads/" />

CREATE TABLE tb_image(
    `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
    `name` varchar(255) NOT NULL COMMENT '文件名',
    `image` longblob NOT NULL COMMENT '图片数据',
    PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='图片表';

public void addImage(String name, String imagePath) {
    try {
        FileInputStream fis = new FileInputStream(imagePath);
        PreparedStatement pstmt = conn.prepareStatement("INSERT INTO tb_image(name,image) VALUES(?,?)");
        pstmt.setString(1, name);  // 设置文件名
        pstmt.setBinaryStream(2, fis, fis.available());  // 设置图片数据
        pstmt.executeUpdate();
        pstmt.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public void getImage(int id, HttpServletResponse response) {
    try {
        PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM tb_image WHERE id=?");
        pstmt.setInt(1, id);
        ResultSet rs = pstmt.executeQuery();
        if (rs.next()) {
            String name = rs.getString("name");
            Blob imageBlob = rs.getBlob("image");
            InputStream is = imageBlob.getBinaryStream();
            ServletOutputStream out = response.getOutputStream();
            response.setContentType("image/jpeg");
            response.setHeader("Content-Disposition", "attachment;filename=" + name);
            byte[] b = new byte[1024];
            int len;
            while ((len = is.read(b)) > 0) {
                out.write(b, 0, len);
            }
            is.close();
            out.flush();
            out.close();
        }
        rs.close();
        pstmt.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

<img src="/getImage?id=1" />