文件上传和下载

 

 

 

 

 

 

 

 

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import com.rome.backend.common.R;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import org.springframework.web.multipart.MultipartFile;

 

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServletResponse;

import java.io.File;

import java.io.FileInputStream;

 

import java.io.IOException;

import java.util.UUID;

 

/**

 * 文件上传下载

 */

@RestController

@RequestMapping("/common")

public class CommonController {

    /**

     * 上传

     * @param file

     * @return

     */

    @PostMapping("/upload")

    public R<String> upload(MultipartFile file){//参数名和前端input名一样

        //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除

        //获取当前项目路径进行拼接

       String url = System.getProperty("user.dir")+"\\backend\\src\\main\\resources\\backend\\images\\dish\\dishload\\";

       //使用uuid重新生成文件名防止文件名重复造成覆盖，uuid+原始文件名

        String uuid = UUID.randomUUID().toString();

//        uuid+原始文件名

        String fileName = uuid.concat(file.getOriginalFilename());

 

//        将文件转存

        try {

            file.transferTo(new File(url+fileName));

        } catch (IOException e) {

            throw new RuntimeException(e);

        }

        return R.success(fileName);

    }

 

    /**

     * 下载

     * @param name

     * @param response

     */

    @GetMapping("/download")

    public void download(String name, HttpServletResponse response){

        //图片路径

        String urlImg = System.getProperty("user.dir")+"\\backend\\src\\main\\resources\\backend\\images\\dish\\dishload\\".concat(name);

        try {

            //通过输入流读取文件内容

            FileInputStream fileInputStream = new FileInputStream(new File(urlImg));

             

 

            //输出流到浏览器

 

            ServletOutputStream outputStream = response.getOutputStream();

 

            //设置响应回去的是什么类型的文件

            response.setContentType("image/jpeg");

 

            int len = 0;

            byte[] bytes = new byte[1024];

            while ((len = fileInputStream.read(bytes)) != -1){

                outputStream.write(bytes,0,len);

                outputStream.flush();

            }

            //关闭资源

            outputStream.close();

            fileInputStream.close();

 

        } catch (Exception e) {

           e.printStackTrace();

        }

       

    }

}