需求

要实现的功能是：实现一个可以支持minio+oss两种方式，上传下载文件的自定义依赖。其中还包括一些创建桶、删除桶、删除文件等功能，但是最主要的是实现自动配置。

如果对spring理解很深的话，自动配置这些东西很容易理解，但是对于技术小白来讲只能按葫芦画瓢。

首先，StorageManager是我的自定义依赖对外提供的要注入spring的对象，其中的方法是对外提供的方法，方法返回的是StorageService接口。

package cn.chinatelecom.dxsc.park.oss;import cn.chinatelecom.dxsc.park.oss.entity.FileDomain;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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;public class StorageManager {private static final Logger log = LoggerFactory.getLogger(StorageManager.class);private final StorageService storageService;public StorageManager(StorageService storageService) {this.storageService = storageService;}/*** 创建存储桶** @param bucketName 桶名称*/public void createBucket(String bucketName) {storageService.createBucket(bucketName);}/*** 删除桶* @param bucketName 桶名称* @return*/public Boolean removeBucket(String bucketName) {Boolean removeBucket = storageService.removeBucket(bucketName);return removeBucket;}/*** 删除文件* @param fileName* @return*/public Boolean remove(String fileName){return storageService.remove(fileName);}/*** 下载文件** @param filePath 文件路径* @return 文件流*/public InputStream getObject(String filePath) {return storageService.getObject(filePath);}/*** 上传文件* @param file* @return*/public FileDomain saveFile(MultipartFile file) {FileDomain result = new FileDomain();try {InputStream in = file.getInputStream();long size = file.getSize();String contentType = file.getContentType();String fileName = generateName(file.getOriginalFilename());String filePath = generateKey(fileName);String url = storageService.saveFile(in, size, contentType, filePath);result.setSize(size);result.setUrl(url);result.setKey(filePath);result.setType(contentType);} catch (IOException e) {log.error("保存文件失败", e);throw new RuntimeException(e);}return result;}private String generateName(String originalFilename) {return UUID.randomUUID().toString().replace("-", "")  + originalFilename.substring(originalFilename.lastIndexOf("."));}private String generateKey(String fileName) {// 2022-10/24/b4c9106e3f574a61841ce4624494f0cc.jpg  在删除和下载文件时需要传入路径才可以删除和下载return LocalDate.now().format(DateTimeFormatter.ofPattern("yyyy-MM/dd")) + "/" + fileName;}}

StorageService接口定义：

package cn.chinatelecom.dxsc.park.oss;import io.minio.errors.*;import java.io.IOException;
import java.io.InputStream;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;public interface StorageService {/*** 创建存储桶* @param bucketName 桶名称*/void createBucket(String bucketName);/*** 存储文件* @param inputStream 文件流* @param fileSize 文件大小* @param contentType 文件类型* @param keyName 文件名及路径*/String saveFile(InputStream inputStream, long fileSize, String contentType, String keyName);/*** 下载文件* @param filePath 文件路径* @return*/InputStream getObject(String filePath);/*** 删除文件* @param fileName* @return*/Boolean remove(String fileName);/*** 删除桶* @param bucketName 桶名称* @return*/Boolean removeBucket(String bucketName);
}

FileDomain是上传文件时返回的对象，其中包括文件url，文件在服务器的存储路径，文件类型、大小等等可以自己定义，这里没有使用@Data注解而是手写get和set方法，没有引入Lombok依赖是因为在实现自定义依赖的时候，尽量能不引入依赖就不引入依赖。如果你在自定义依赖里面引入版本2.0的Lombok，但是当别人引用你的依赖的时候，同时也引用的1.0的Lombok，这样就会出现最让人头疼的版本冲突问题，为了避免这种问题出现，尽量不要在底层引用过多依赖。

package cn.chinatelecom.dxsc.park.oss.entity;public class FileDomain {/*** 路径名称*/private String key;/*** 文件url*/private String url;/*** 文件类型（contentType）*/private String type;/*** 文件大小*/private Long size;public String getKey() {return key;}public void setKey(String key) {this.key = key;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public String getType() {return type;}public void setType(String type) {this.type = type;}public Long getSize() {return size;}public void setSize(Long size) {this.size = size;}
}

接下来是自动配置的相关代码
DxscStorageProperties是需要配置的一些属性，比如accessKey以及accessSecret等等。
@ConfigurationProperties注解，在 SpringBoot 中，当想需要获取到配置文件数据时，除了可以用 Spring 自带的 @Value 注解外，SpringBoot 还提供了一种更加方便的方式：@ConfigurationProperties。只要在 Bean 上添加上了这个注解，指定好配置文件的前缀，那么对应的配置文件数据就会自动填充到 Bean 中。

package cn.chinatelecom.dxsc.park.oss.config;import org.springframework.boot.context.properties.ConfigurationProperties;@ConfigurationProperties(prefix = "dxsc.storage")
public class DxscStorageProperties {/*** 激活哪种存储*/private String active;/*** oss地址*/private String endpoint;/*** 桶名称*/private String bucketName;private String accessKey;private String accessSecret;public String getActive() {return active;}public void setActive(String active) {this.active = active;}public String getEndpoint() {return endpoint;}public void setEndpoint(String endpoint) {this.endpoint = endpoint;}public String getBucketName() {return bucketName;}public void setBucketName(String bucketName) {this.bucketName = bucketName;}public String getAccessKey() {return accessKey;}public void setAccessKey(String accessKey) {this.accessKey = accessKey;}public String getAccessSecret() {return accessSecret;}public void setAccessSecret(String accessSecret) {this.accessSecret = accessSecret;}}

接下来的代码才是重中之重DxscStorageAutoConfiguration，此类将DxscStorageProperties注入到spring中，Spring Boot 会扫描到类路径下的META-INF/spring.factories配置文件，把DxscStorageAutoConfiguration对应的的Bean值添加到容器中。

package cn.chinatelecom.dxsc.park.oss.autoconfigure;import cn.chinatelecom.dxsc.park.oss.StorageManager;
import cn.chinatelecom.dxsc.park.oss.StorageService;
import cn.chinatelecom.dxsc.park.oss.config.DxscStorageProperties;
import cn.chinatelecom.dxsc.park.oss.impl.MinioStorageServiceImpl;
import cn.chinatelecom.dxsc.park.oss.impl.OssStorageServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@EnableConfigurationProperties(DxscStorageProperties.class)
@Configuration
public class DxscStorageAutoConfiguration {@Autowiredprivate DxscStorageProperties dxscStorageProperties;@Beanpublic StorageManager storageManager(StorageService storageService) {return new StorageManager(storageService);}@Bean@ConditionalOnProperty(prefix = "dxsc.storage", value = "active", havingValue = "minio")public StorageService minioService() {return new MinioStorageServiceImpl(dxscStorageProperties);}
//prefix为前缀，value为选择哪个属性，havingValue就是启用哪种方式，当active属性为minio时就调用上面的，oss就调用下面的，
//大概就是这个意思@Bean@ConditionalOnProperty(prefix = "dxsc.storage", value = "active", havingValue = "oss")public StorageService OssService() {return new OssStorageServiceImpl(dxscStorageProperties);}}

spring.factories文件：

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
cn.chinatelecom.dxsc.park.oss.autoconfigure.DxscStorageAutoConfiguration

目录结构
其中MinioStorageServiceImpl和OssStorageServiceImpl就是实现的文件上传下载的接口，再此展示minion的接口：
oss接口可以查看官方文档，其中写得很清楚。

package cn.chinatelecom.dxsc.park.oss.impl;import cn.chinatelecom.dxsc.park.oss.StorageService;
import cn.chinatelecom.dxsc.park.oss.config.DxscStorageProperties;
import io.minio.*;
import io.minio.http.Method;import java.io.InputStream;public class MinioStorageServiceImpl implements StorageService {private final DxscStorageProperties dxscStorageProperties;private final MinioClient minioClient;public MinioStorageServiceImpl(DxscStorageProperties dxscStorageProperties) {this.dxscStorageProperties =dxscStorageProperties;this.minioClient = MinioClient.builder().endpoint(dxscStorageProperties.getEndpoint()).credentials(dxscStorageProperties.getAccessKey(), dxscStorageProperties.getAccessSecret()).build();}@Overridepublic void createBucket(String bucketName){boolean isExist = false;// 检查存储桶是否已经存在try{isExist = minioClient.bucketExists(BucketExistsArgs.builder().bucket(bucketName).build());if (!isExist) {//创建桶minioClient.makeBucket(MakeBucketArgs.builder().bucket(bucketName).build());minioClient.setBucketPolicy(SetBucketPolicyArgs.builder().bucket(bucketName).config("{\"Version\":\"2023-2-20\",\"Statement\":[]}").build());}}catch (Exception e){throw new RuntimeException(e);}}@Overridepublic String saveFile(InputStream inputStream, long fileSize, String contentType, String keyName) {try {PutObjectArgs objectArgs = PutObjectArgs.builder().bucket(dxscStorageProperties.getBucketName()).object(keyName).stream(inputStream, fileSize, -1).contentType(contentType).build();//文件名称相同会覆盖minioClient.putObject(objectArgs);// 查看文件地址GetPresignedObjectUrlArgs build = new GetPresignedObjectUrlArgs().builder().bucket(dxscStorageProperties.getBucketName()).object(keyName).method(Method.GET).build();try {return minioClient.getPresignedObjectUrl(build);} catch (Exception e) {throw new RuntimeException(e);}} catch (Exception e) {throw new RuntimeException(e);}}@Overridepublic InputStream getObject(String filePath) {try{GetObjectArgs objectArgs = GetObjectArgs.builder().bucket(dxscStorageProperties.getBucketName()).object(filePath).build();return minioClient.getObject(objectArgs);}catch (Exception e){System.out.println("下载失败");throw new RuntimeException(e);}}@Overridepublic Boolean remove(String fileName) {try {minioClient.removeObject(RemoveObjectArgs.builder().bucket(dxscStorageProperties.getBucketName()).object(fileName).build());} catch (Exception e) {return false;}return true;}@Overridepublic Boolean removeBucket(String bucketName) {try {//在删除桶时，需要注意一下不能删除自身，当你的配置文件里的bucketName的test时还要删除test，是不能删除成功的//bucketName为test1时，删除test，是可以的minioClient.removeBucket(RemoveBucketArgs.builder().bucket(bucketName).build());} catch (Exception e) {return false;}return true;}
}

至此，自定义依赖完成，接下来是引用，引用方法为先将自定义依赖上传至本地maven库，然后才可以导入依赖，

		<dependency><artifactId>dxsc-park-frame-oss</artifactId><groupId>cn.chinatelecom</groupId><version>1.0.0-SNAPSHOT</version></dependency>

然后，配置minio或者oss的accessKey和accessSecret等属性：
（active为minio就是通过minion方式实现文件上传下载）

dxsc:storage:active: minioendpoint: http://***.168.30.27:9000bucketName: dxsc-parkaccessKey: minioadminaccessSecret: minioadmin
#  storage:
#    active: oss
#    endpoint: https://oss-cn-beijing.aliyuncs.com
#    bucketName: dxsc-park
#    accessKey: ***
#    accessSecret: ***
server:port: 1101

最后注入StorageManager，在一开始的时候就说过StorageManager是对外提供的：

package cn.chinatelecom.dxsc.park.test.controller;import cn.chinatelecom.dxsc.park.oss.StorageManager;
import cn.chinatelecom.dxsc.park.oss.entity.FileDomain;
import org.apache.tomcat.util.http.fileupload.IOUtils;
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.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;@RestController
@RequestMapping("/minio")
public class TestController {@Autowiredprivate StorageManager storageManager;@PostMapping("/createBucket")public void createBucket(@RequestParam("bucketName") String bucketName){storageManager.createBucket(bucketName);}@PostMapping("/removeBucket")public void removeBucket(@RequestParam("bucketName") String bucketName){storageManager.removeBucket(bucketName);}@PostMapping("/upload")public String upload(@RequestParam("file") MultipartFile file){FileDomain fileDomain = storageManager.saveFile(file);System.out.println(fileDomain.getUrl());return fileDomain.getKey();}@PostMapping("/remove")public Boolean remove(@RequestParam("fileName") String fileName){Boolean remove = storageManager.remove(fileName);return remove;}@PostMapping("/getObject")public void getObject(@RequestParam("filePath") String filePath, HttpServletResponse response) throws IOException {InputStream object = storageManager.getObject(filePath);response.setContentType("application/octet-stream");response.addHeader("Content-Disposition", "attachment;filename=" + "fileName");IOUtils.copy(object, response.getOutputStream());IOUtils.closeQuietly(object);}}