1). 定义OSS相关配置

在sky-server模块

application-dev.yml

sky:alioss:endpoint: oss-cn-hangzhou.aliyuncs.comaccess-key-id: LTAI5tPeFLzsPPT8gG3LPW64access-key-secret: U6k1brOZ8gaOIXv3nXbulGTUzy6Pd7bucket-name: sky-take-out

application.yml

spring:profiles:active: dev    #设置环境
sky:alioss:endpoint: ${sky.alioss.endpoint}access-key-id: ${sky.alioss.access-key-id}access-key-secret: ${sky.alioss.access-key-secret}bucket-name: ${sky.alioss.bucket-name}

2). 读取OSS配置

在sky-common模块中，已定义

package com.sky.properties;import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;@Component
@ConfigurationProperties(prefix = "sky.alioss")
@Data
public class AliOssProperties {private String endpoint;private String accessKeyId;private String accessKeySecret;private String bucketName;}

3). 生成OSS工具类对象

在sky-server模块

package com.sky.config;import com.sky.properties.AliOssProperties;
import com.sky.utils.AliOssUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** 配置类，用于创建AliOssUtil对象*/
@Configuration
@Slf4j
public class OssConfiguration {@Bean@ConditionalOnMissingBeanpublic AliOssUtil aliOssUtil(AliOssProperties aliOssProperties){log.info("开始创建阿里云文件上传工具类对象：{}",aliOssProperties);return new AliOssUtil(aliOssProperties.getEndpoint(),aliOssProperties.getAccessKeyId(),aliOssProperties.getAccessKeySecret(),aliOssProperties.getBucketName());}
}

其中，AliOssUtil.java已在sky-common模块中定义

package com.sky.utils;import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import java.io.ByteArrayInputStream;@Data
@AllArgsConstructor
@Slf4j
public class AliOssUtil {private String endpoint;private String accessKeyId;private String accessKeySecret;private String bucketName;/*** 文件上传** @param bytes* @param objectName* @return*/public String upload(byte[] bytes, String objectName) {// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);try {// 创建PutObject请求。ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(bytes));} catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}//文件访问路径规则 https://BucketName.Endpoint/ObjectNameStringBuilder stringBuilder = new StringBuilder("https://");stringBuilder.append(bucketName).append(".").append(endpoint).append("/").append(objectName);log.info("文件上传到:{}", stringBuilder.toString());return stringBuilder.toString();}
}

4). 定义文件上传接口

在sky-server模块中定义接口

package com.sky.controller.admin;import com.sky.constant.MessageConstant;
import com.sky.result.Result;
import com.sky.utils.AliOssUtil;
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.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 java.io.IOException;
import java.util.UUID;/*** 通用接口*/
@RestController
@RequestMapping("/admin/common")
@Api(tags = "通用接口")
@Slf4j
public class CommonController {@Autowiredprivate AliOssUtil aliOssUtil;/*** 文件上传* @param file* @return*/@PostMapping("/upload")@ApiOperation("文件上传")public Result<String> upload(MultipartFile file){log.info("文件上传：{}",file);try {//原始文件名String originalFilename = file.getOriginalFilename();//截取原始文件名的后缀   dfdfdf.pngString extension = originalFilename.substring(originalFilename.lastIndexOf("."));//构造新文件名称String objectName = UUID.randomUUID().toString() + extension;//文件的请求路径String filePath = aliOssUtil.upload(file.getBytes(), objectName);return Result.success(filePath);} catch (IOException e) {log.error("文件上传失败：{}", e);}return Result.error(MessageConstant.UPLOAD_FAILED);}
}

提示：
@ConditionalOnMissingBean是用于修饰Bean的一个注解，在项目启动时开始自动化配置注册生成Bean，当某个类型的Bean被注册之后，如果再注册相同类型的Bean就会失败，该注解会保证Spring容器中只有一个Bean类型的实例，当注册多个相同类型的Bean时，会出现异常。当一个接口有多个实现类时，如果只希望它有一个实现类，那就在其他的各个实现类上加上这个注解。
@ConditionalOnMissingBean作用在@Bean定义上，也就是说在容器加载它作用的Bean时，检查容器中是否存在目标类型（@ConditionalOnMissingBean注解的value值）的Bean了，如果存在则跳过Bean的默认加载动作，如果不存在则加载该Bean完成注册。
参考：参考文章