基于七牛云上传，下载文件

本文主要是介绍基于七牛云上传，下载文件，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

准备工作

1.创建一个七牛云账号

2.登录账号，进入个人中心，创建一组密钥（ak和sk）

3. 创建一个公有的存储空间（桶）

注：存储地区的选择基于你的用户的分布主要在哪里。

七牛云直接白送10GB给我们玩，很适合做项目想白嫖的小伙伴。

实战演练

Java SDK_SDK 下载_对象存储 - 七牛开发者中心（这里的代码仅供参考）

1.springboot项目中导入必要的依赖

        <!--        七牛云--><dependency><groupId>com.qiniu</groupId><artifactId>qiniu-java-sdk</artifactId><version>[7.13.0, 7.13.99]</version></dependency><!--        gson,上传文件时要用--><dependency><groupId>com.google.code.gson</groupId><artifactId>gson</artifactId><version>2.8.5</version><scope>compile</scope></dependency><!--        @ConfigurationProperties注解爆红--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional></dependency>

2.yml文件中填入ak，sk和桶的相关配置

qiniu:accessKey: z3214mq2xG5w7-KHQk7oBiJC6sbjrjmlVNai0saisecretKey: _wys_Vf2RWpZqG9Hnlq32lQ17wvULnHeJSIjnGezbucket: gmgx2024prefixUrl: http://siz0shti6.jl-cnm.clouddn.com/

prefixUrl在这

3.写一个QiniuConfig来接收这些配置

@ConfigurationProperties(prefix = "qiniu")
@Data
@Component
public class QiniuConfig {private String accessKey;private String secretKey;private String bucket;private String prefixUrl;
}

4.编写上传文件的核心代码

为什么只有上传？因为这个桶是公有的，只需要上传时把返回的url存到数据库中，要下载文件时输入url即可下载。(最后介绍私有桶的上传和下载)

控制器

@Tag(name="文件控制器",description = "基于七牛云实现文件上传和下载")
@RestController
@RequestMapping("file")
public class FileController {@Autowiredprivate FileService fileService;@Operation(summary = "uploadFile",description = "基于七牛云上传文件")@PostMapping("/uploadFile")public Result uploadFile(MultipartFile file){String url = fileService.upload(file);if(url!=null){return new Result(Code.UPLOAD_SUCCESS,"文件上传成功",url);}return new Result(Code.UPLOAD_FAIL,"文件上传失败",null);}}

服务类

package com.example.qiniufileupload.service.impl;
import com.example.qiniufileupload.config.QiniuConfig;
import com.example.qiniufileupload.service.FileService;
import com.google.gson.Gson;
import com.qiniu.common.Zone;
import com.qiniu.http.Response;
import com.qiniu.storage.Configuration;
import com.qiniu.storage.UploadManager;
import com.qiniu.storage.model.DefaultPutRet;
import com.qiniu.util.Auth;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import java.io.IOException;
import java.io.InputStream;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.UUID;@Service
public class FileServiceImpl implements FileService {@Autowiredprivate QiniuConfig qiniuConfig;/*** * @param file   要上传到七牛云的文件* @return url   上传后的文件的完整url*/public String upload(MultipartFile file) {try {// 获取文件的名字   aaa.jpgString originalFilename = file.getOriginalFilename();//file扩展名 extendFileName    jpgString extendFileName = originalFilename.substring(originalFilename.lastIndexOf("."));// 默认不指定key的情况下，以文件内容的hash值作为文件名 时间日期前缀LocalDate currentDate = LocalDate.now();DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy/MM/dd/");// todo:构建新的文件名    2024/8/29/一个uuid.jpgString key = currentDate.format(formatter) + UUID.randomUUID().toString().replace("-", "") + extendFileName;// 构造一个带指定 Region 对象的配置类Configuration zone = new Configuration(Zone.huanan());//我们刚开始选的是华南地区// 从 MultipartFile 直接获取输入流，避免先保存到本地再上传InputStream inputStream = file.getInputStream();//创建Auth对象，填写ak和skAuth auth = Auth.create(qiniuConfig.getAccessKey(), qiniuConfig.getSecretKey());//获得上传凭证String upToken = auth.uploadToken(qiniuConfig.getBucket());System.out.println(upToken);//z3214mq2xG5w7-KHQk7oBiJC6zojrjmlVNcn0sai:oHRCCHPiB2YlJxxCYtDyVOb3lCs=:eyJzY29wZSI6ImdtZ3gyMDI0IiwiZGVhZGxpbmUiOjE3MjQ5Mjc2NjN9//隐藏了判空条件try (InputStream ignored = inputStream){UploadManager uploadManager = new UploadManager(zone);//指定zone//上传图片到七牛云Response response = uploadManager.put(inputStream, key, upToken,null,null);/*** 用gson将浏览器响应的body字符串解析成DefaultPutRet的实例化对象*                                     ↓*          public final class DefaultPutRet {*              public String hash;*              public String key;//在七牛云存储空间中的名字**              public DefaultPutRet() {*              }*          }**/DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);String url = "";url = qiniuConfig.getPrefixUrl() + putRet.key;return url;} catch (IOException ex) {return null;}} catch (Exception e) {return null;}}}

5.用knife4j测试一下

首先随便找一张图片（bushi）

在knife4j的界面中选择这个文件并上传

拿到返回的url地址

在七牛云中我们保存的文件夹中看到了我们刚上传的图片

使用情景

做需要上传文件的相关业务时，我们可以把上传成功后文件的url保存到数据库中，在需要时直接查数据库获取文件的url，在前端做对应的回显即可。

*************************************************************************

私有桶的上传和下载

1.创建一个私有桶

2.修改相关配置

3.编写上传和下载的核心代码

控制器

@Tag(name="文件控制器",description = "基于七牛云实现文件上传和下载")
@RestController
@RequestMapping("file")
public class FileController {@Autowiredprivate FileService fileService;@Operation(summary = "uploadFile",description = "基于七牛云上传文件")@PostMapping("/uploadFile")public Result uploadFile(MultipartFile file){String url = fileService.upload(file);if(url!=null){return new Result(Code.UPLOAD_SUCCESS,"文件上传成功",url);}return new Result(Code.UPLOAD_FAIL,"文件上传失败",null);}@Operation(summary = "downloadFile",description = "基于七牛云下载文件")@PostMapping("/downloadFile/{fileName}")public Result downloadFile(@PathVariable String fileName){String url = fileService.download(fileName);if(url!=null){return new Result(Code.DOWNLOAD_SUCCESS,"文件下载成功",url);}return new Result(Code.DOWNLOAD_FAIL,"文件下载失败",null);}}

服务类

@Service
public class FileServiceImpl implements FileService {@Autowiredprivate QiniuConfig qiniuConfig;/**** @param file   要上传到七牛云的文件* @return url   上传后的文件的完整url*/public String upload(MultipartFile file) {try {// 获取文件的名字   aaa.jpgString originalFilename = file.getOriginalFilename();//file扩展名 extendFileName    jpgString extendFileName = originalFilename.substring(originalFilename.lastIndexOf("."));String key =  UUID.randomUUID().toString().replace("-", "") + extendFileName;// 构造一个带指定 Region 对象的配置类Configuration zone = new Configuration(Zone.huanan());//我们刚开始选的是华南地区// 从 MultipartFile 直接获取输入流，避免先保存到本地再上传InputStream inputStream = file.getInputStream();//创建Auth对象，填写ak和skAuth auth = Auth.create(qiniuConfig.getAccessKey(), qiniuConfig.getSecretKey());//获得上传凭证String upToken = auth.uploadToken(qiniuConfig.getBucket());System.out.println(upToken);//z3214mq2xG5w7-KHQk7oBiJC6zojrjmlVNcn0sai:oHRCCHPiB2YlJxxCYtDyVOb3lCs=:eyJzY29wZSI6ImdtZ3gyMDI0IiwiZGVhZGxpbmUiOjE3MjQ5Mjc2NjN9//隐藏了判空条件try (InputStream ignored = inputStream){UploadManager uploadManager = new UploadManager(zone);//指定zone//上传图片到七牛云Response response = uploadManager.put(inputStream, key, upToken,null,null);DefaultPutRet putRet = new Gson().fromJson(response.bodyString(), DefaultPutRet.class);String url = "";url = qiniuConfig.getPrefixUrl() + putRet.key;return url;} catch (IOException ex) {return null;}} catch (Exception e) {return null;}}@Overridepublic String download(String fileName) {String urlString = "";try {// domain   下载 domain, eg: qiniu.com【必须】// useHttps 是否使用 https【必须】// key      下载资源在七牛云存储的 key【必须】String domain = qiniuConfig.getPrefixUrl();//todo 需要修改domainDownloadUrl url = new DownloadUrl(domain, qiniuConfig.getUseHttps(), fileName);// 带有效期long expireInSeconds = 60;long deadline = System.currentTimeMillis() / 1000 + expireInSeconds;Auth auth = Auth.create(qiniuConfig.getAccessKey(), qiniuConfig.getSecretKey());urlString = url.buildURL(auth, deadline);System.out.println(urlString);} catch (Exception e) {e.printStackTrace();}return urlString;}}