做一个上传图片到阿里云OSS的API接口并限制图片的大小且用MD5校验和命名文件

背景：在学习的java的时候，大佬给了一个需求作为训练：做一个上传图片的接口，传到oss，返回一个url。

阿里云oss对象存储OSS：github项目地址

导入POM依赖

<dependency>
     <groupId>com.alibaba.cloud</groupId>
     <artifactId>spring-cloud-starter-alicloud-oss</artifactId>
     <version>2.2.0.RELEASE</version>
</dependency>

Spring Boot 的properties.yml配置

Spring:
  cloud:
    alicloud:
      access-key: 
      secret-key: 
      oss:
        endpoint: oss-cn-hangzhou.aliyuncs.com
        bucketname: 

创建OSS工具类

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class OssUtil implements InitializingBean {
    @Value("${spring.cloud.alicloud.oss.endpoint}")
    private String endpoint;
    @Value("${spring.cloud.alicloud.access-key}")
    private String accessKeyID;
    @Value("${spring.cloud.alicloud.secret-key}")
    private String accesskeySecret;
    @Value("${spring.cloud.alicloud.oss.bucketname}")
    private String bucketName;

    public static String END_POINT;
    public static String ACCESS_KEY_ID;
    public static String ACCESS_KEY_SECRET;
    public static String BUCKET_NAME;

    //编写一个工具类，读取配置文件，其中InitializingBean是为了复制给public静态变量，afterPropertiesSet()会在容器加载完后执行。
    @Override
    public void afterPropertiesSet() throws Exception {
        END_POINT = endpoint;
        ACCESS_KEY_ID = accessKeyID;
        ACCESS_KEY_SECRET = accesskeySecret;
        BUCKET_NAME = bucketName;
    }

}

创建OSS 的Service接口

import org.springframework.web.multipart.MultipartFile;

public interface OssService {
    String uploadFile(MultipartFile file);
}

实现类

import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.model.PutObjectResult;
import com.kiseki.service.OssService;
import com.kiseki.util.OssUtil;
import lombok.extern.slf4j.Slf4j;
import org.joda.time.DateTime;
import org.springframework.stereotype.Service;
import org.springframework.util.DigestUtils;
import org.springframework.web.multipart.MultipartFile;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

@Service
@Slf4j
public class OssServiceImpl implements OssService {


    @Override
    public String uploadFile(MultipartFile file) {
        //赋值
        String url = null;
        String endpoint = OssUtil.END_POINT;
        String accessKeyId = OssUtil.ACCESS_KEY_ID;
        String accessKeySecret = OssUtil.ACCESS_KEY_SECRET;
        String bucketName = OssUtil.BUCKET_NAME;
        //建立oss连接，通过地址和密钥
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
        try {
            //需要2个流，1个流给MD5处理，一个流为了上传到Oss。https://blog.csdn.net/xueyijin/article/details/121526772
            InputStream inputStream = file.getInputStream();
            //以下思路是创建一个输出流来缓存
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len;
            while ((len = inputStream.read(buffer)) > -1) {
                baos.write(buffer, 0, len);
            }
            baos.flush();
            String md5 = DigestUtils.md5DigestAsHex(baos.toByteArray());
            log.info("md5:{}", md5);//可以看出这也是md5
            InputStream inputStreamForMD5 = new ByteArrayInputStream(baos.toByteArray());
            InputStream inputStreamForOss = new ByteArrayInputStream(baos.toByteArray());
            /*其实用下面这个也是一样的，但是哪个更高效和通用？？？
            InputStream inputStreamForMD5 = file.getInputStream();
            InputStream inputStreamForOss = file.getInputStream();
             */
            //获取上传的文件的名字
            String filename = file.getOriginalFilename();
            //获得后缀
            String fileSuffix = filename.substring(file.getOriginalFilename().lastIndexOf("."));
            //随机uuid是为了拼接文件名，防止用户上传两个名字相同的文件后覆盖掉前一个
            //UUID uuid = UUID.randomUUID();
            //获取一个md加密
            String md5OfFileName = DigestUtils.md5DigestAsHex(inputStreamForMD5);
            //这里是为了按上传时间分配目录。精确到月,这里用到一个第三方的jar包，记得笔记2022/5/18
            String dateMark = DateTime.now().toString("yyyyMMdd/");
            //拼接成完整的文件名。
            final String uploadKey = dateMark + md5OfFileName + fileSuffix;
            log.info("uploadKey:{}", uploadKey);
            //传入三个参数，上传
            PutObjectResult putObjectResult = ossClient.putObject(bucketName, uploadKey, inputStreamForOss);
            //阿里云返回eTag为全大写的md5值
            String eTag = putObjectResult.getETag();
            log.info("eTag:{}", eTag);
            //拼接url，这个就是地址
            url = "https://" + bucketName + "." + endpoint + "/" + uploadKey;
            log.info("Image URL：{}", url);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            ossClient.shutdown();
        }
        return url;
    }
}

接口代码：

import com.kiseki.service.OssService;
import com.kiseki.vo.ApiResponse;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

@RestController
@RequestMapping("api/Upload")
@Api(tags = "上传数据接口")
@Validated
@Slf4j
@CrossOrigin
public class UploadAPI {
    @Autowired
    OssService ossService;

    @ApiOperation(value = "上传图片", notes = "图片需为jpg,jpeg,gif,png格式。")
    @PostMapping("/OssImage")
    public ApiResponse uploadImage(@RequestPart("图片") MultipartFile image) {
        if (image.getSize() > 1024 * 1024 * 5) {
            return ApiResponse.fail("附件大小不能大于5M");
        }
        //下面判断，图片的格式需要是jpg,jpeg,gif,png格式
        String pictureSuffix = image.getOriginalFilename().substring(image.getOriginalFilename().lastIndexOf(".") + 1);
        if (!"jpg,jpeg,gif,png".toUpperCase().contains(pictureSuffix.toUpperCase())) {
            return ApiResponse.fail("请选择jpg,jpeg,gif,png格式的图片");
        }
        return ApiResponse.success(ossService.uploadFile(image));
    }

}

此处自己遇到了一个问题，记录一下，inputstream用了2次，一次流是为了传图片，一次是为了获取md5，主要是为了直接oss命名图片。