更优雅的生成（策略或者工厂模式？）

傻傻的不知道怎么起文章标题

以前使用的方式

public Class A{
public static Map <String,FatherClass> map = new HashMap<>(16);

static{
map.put(son1Name,son1Class);
map.put(son2Name,son2Class);
}
}

现在使用的方式

自定义注解

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Component
public @interface FileStoreWay {

    String value() default "common";
}

子类（添加自定义注解@FileStoreWay）

package com.hito.base;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.transfer.Download;
import com.amazonaws.services.s3.transfer.TransferManager;
import com.amazonaws.services.s3.transfer.Upload;
import com.hito.annotate.FileStoreWay;
import com.hito.entity.FileInfo;
import com.hito.enums.BucketEnum;
import com.hito.enums.FileTypeEnum;
import com.hito.mapper.FileInfoMapper;
import com.hito.util.CephConnectionFactory;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;

/**
 * @author fuchanghai
 */
@FileStoreWay(value = "ceph")
@Slf4j
public class CephFileOperate extends FileOperate {
    @Value("${fileRootPath}")
    private String fileRootPath;


    @Value("${downloadRootPath}")
    private String downloadRootPath;


    @Autowired
    FileInfoMapper fileInfoMapper;

    @Autowired
    CephConnectionFactory cephConnectionFactory;

    @Override
    public void uploadFile(HttpServletRequest request, MultipartFile file) throws IOException {
        uploadFile(request, file, BucketEnum.DEFAULT.name());
    }

    public void uploadFile(HttpServletRequest request, MultipartFile file, String bucketName) throws IOException {
        File dest = new File(fileRootPath + file.getOriginalFilename());
        file.transferTo(dest);
        fragmentUpload(request.getRemoteHost(), dest, bucketName);
    }

    @Override
    public void fragmentUpload(String ip, File dest) {
        fragmentUpload(ip, dest, BucketEnum.DEFAULT.name());
    }

    @Override
    public File download(FileInfo fileInfo) {
        File file = new File(downloadRootPath + fileInfo.getName());
        AmazonS3 connection = cephConnectionFactory.getConnection();
        TransferManager transferManager = new TransferManager(connection);
        Download download = transferManager.download(fileInfo.getBucketName(), fileInfo.getName(), file);
        try {
            download.waitForCompletion();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return file;
    }


    public void fragmentUpload(String ip, File dest, String bucketName) {
        AmazonS3 connection = cephConnectionFactory.getConnection();
        Bucket newBucket = connection.createBucket(bucketName);
        TransferManager transferManager = new TransferManager(connection);
        Upload upload = transferManager.upload(bucketName, dest.getName(), dest);

        try {
            upload.waitForCompletion();
            log.info("Upload complete.");
        } catch (AmazonClientException amazonClientException) {
            log.info("Unable to upload file, upload was aborted.");
            amazonClientException.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        insertFileInfo(ip, dest, bucketName, FileTypeEnum.CEPH.code(), fileInfoMapper);

    }


    @Override
    public void say() {
        System.out.println("ceph 类");
    }
}

@Configuration
public class AllFileOperate implements ApplicationContextAware {
    public static HashMap<String, FileOperate> fileOperates = new HashMap<>();

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    //获取所有加了此注解的类
        String[] beanNames = applicationContext.getBeanNamesForAnnotation(FileStoreWay.class);
        for (String beanName : beanNames
        ) {
            FileOperate bean = applicationContext.getBean(beanName, FileOperate.class);
            fileOperates.put(beanName, bean);
        }
    }
}

controller 调用

    @PostMapping("/upload")
    public ApiResponse upload(HttpServletRequest request, @RequestParam("file") MultipartFile file,
                              @RequestParam(name = "way", defaultValue = "common") String way) throws IOException {
		//way 填的是注解 FileStoreWay 里面的value 值
        FileOperate fileOperate = AllFileOperate.fileOperates.get(way);
        fileOperate.uploadFile(request, file);
        return ApiResponse.responseSuccess();
    }

为什么要绕这么一大圈

笔者上面做的是 上传下载文件接口，有普通上传下载，有上传到ceph 上 也有上传到fastdfs 上，全都继承了FileOperate 抽象类，如果现在进来一个新需求上传到新的存储介质上，只需要继承fileOperate 并在子类上加上注解@FileStoreWay即可。不需要其他操作，可扩展性比上面强