Java实现阿里云oss文预览上传和下载

第一步：引入maven依赖

<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
<!--阿里云oss-->
<dependency>
<groupId>com.aliyun.oss</groupId>
<artifactId>aliyun-sdk-oss</artifactId>
<version>2.8.2</version>
</dependency>　

第二步：阿里云oss工具类

import com.aliyun.oss.OSSClient;
import com.aliyun.oss.model.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.*;

/**
 * 阿里云 OSS文件类
 */
public class AliOssCloudUtil {
    Log log = LogFactory.getLog(AliOssCloudUtil.class);

    /**
     * 用户的存储空间所在数据中心的访问域名
     */
    private String endpoint = "oss-cn-hangzhou.aliyuncs.com";

    /**
     * OSS签名key
     */
    private String accessKeyId = "LTAI5tSJSDtUaXXXX";

    /**
     * OSS签名密钥
     */
    private static final String accessKeySecret = "AQLmguaT1BFsOi5oe07iMUXXXXX";
    /**
     * 存储空间名称
     */
    private static final String bucketName = "oss-uav-oss";


    //文件存储目录
    private String filedir = "uav/";

    private OSSClient ossClient;

    public AliOssCloudUtil() {
        ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);
    }

    public String getFiledir() {
        return this.filedir;
    }

    //自定义上传文件夹
    public AliOssCloudUtil(String filedir) {
        this.filedir = filedir;
        ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);
    }


    /**
     * 初始化
     */
    public void init() {
        ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);
    }

    /**
     * 销毁
     */
    public void destory() {
        ossClient.shutdown();
    }


    /**
     * 上传到OSS服务器
     *
     * @param instream 文件流
     * @param fileName 文件名称 包括后缀名
     * @return 出错返回"" ,唯一MD5数字签名
     */
    public String uploadFile2OSS(InputStream instream, String fileName) {
        String ret = "";
        // 判断bucket是否已经存在,不存在进行创建
        if (!doesBucketExist()) {
            createBucket();
        }
        try {
            //创建上传Object的Metadata
            ObjectMetadata objectMetadata = new ObjectMetadata();
            objectMetadata.setContentLength(instream.available());
            objectMetadata.setCacheControl("no-cache");
            objectMetadata.setHeader("Pragma", "no-cache");
            objectMetadata.setContentType(getcontentType(fileName.substring(fileName.lastIndexOf("."))));
            objectMetadata.setContentDisposition("inline;filename=" + fileName);
            // 指定上传文件操作时是否覆盖同名Object。
            // 不指定x-oss-forbid-overwrite时，默认覆盖同名Object。
            // 指定x-oss-forbid-overwrite为false时，表示允许覆盖同名Object。
            // 指定x-oss-forbid-overwrite为true时，表示禁止覆盖同名Object，如果同名Object已存在，程序将报错。
            objectMetadata.setHeader("x-oss-forbid-overwrite", "false");
            String objectName = filedir + fileName;

            //上传文件
            ossClient.putObject(bucketName, objectName, instream, objectMetadata);
            // 封装  url 路径
            String url = "https://" + bucketName + "." + endpoint + "/" + objectName;
            ret = url;
        } catch (IOException e) {
            log.error(e.getMessage(), e);
        } finally {
            ossClient.shutdown();
            try {
                if (instream != null) {
                    instream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return ret;
    }


    /**
     * 判断文件是否存在。doesObjectExist还有一个参数isOnlyInOSS，
     * 如果为true则忽略302重定向或镜像；如果为false，则考虑302重定向或镜像。
     * yourObjectName 表示上传文件到OSS时需要指定包含文件后缀在内的完整路径，例如abc/efg/123.jpg。
     *
     * @return 存在返回true
     */
    public boolean doesObjectExist(String objectName) {
        boolean exists = ossClient.doesObjectExist(bucketName, filedir + objectName);
        return exists;
    }

    /**
     * 判断Bucket是否存在
     *
     * @return 存在返回true
     */
    public boolean doesBucketExist() {
        boolean exists = ossClient.doesBucketExist(bucketName);
        return exists;
    }

    /**
     * 创建Bucket
     */
    public void createBucket() {
        CreateBucketRequest createBucketRequest = new CreateBucketRequest(bucketName);
        // 设置bucket权限为公共读，默认是私有读写
        createBucketRequest.setCannedACL(CannedAccessControlList.PublicRead);
        // 设置bucket存储类型为低频访问类型，默认是标准类型
        createBucketRequest.setStorageClass(StorageClass.IA);
        boolean exists = ossClient.doesBucketExist(bucketName);
        if (!exists) {
            try {
                ossClient.createBucket(createBucketRequest);
                // 关闭client
                ossClient.shutdown();
            } catch (Exception e) {
                log.error(e.getMessage());
            }
        }
    }

    /**
     * Description: 判断OSS服务文件上传时文件的contentType
     *
     * @param FilenameExtension 文件后缀
     * @return String
     */
    public static String getcontentType(String FilenameExtension) {
        if (".bmp".equalsIgnoreCase(FilenameExtension)) {
            return "image/bmp";
        }
        if (".gif".equalsIgnoreCase(FilenameExtension)) {
            return "image/gif";
        }
        if (".jpeg".equalsIgnoreCase(FilenameExtension)
                || ".jpg".equalsIgnoreCase(FilenameExtension)
                || ".png".equalsIgnoreCase(FilenameExtension)) {
            return "image/jpg";
        }
        if (".html".equalsIgnoreCase(FilenameExtension)) {
            return "text/html";
        }
        if (".txt".equalsIgnoreCase(FilenameExtension)) {
            return "text/plain";
        }
        if (".vsd".equalsIgnoreCase(FilenameExtension)) {
            return "application/vnd.visio";
        }
        if (".ppt".equalsIgnoreCase(FilenameExtension) || "pptx".equalsIgnoreCase(FilenameExtension)) {
            return "application/vnd.ms-powerpoint";
        }
        if (".doc".equalsIgnoreCase(FilenameExtension) || "docx".equalsIgnoreCase(FilenameExtension)) {
            return "application/msword";
        }
        if (".xml".equalsIgnoreCase(FilenameExtension)) {
            return "text/xml";
        }
        if (".mp4".equalsIgnoreCase(FilenameExtension)) {
            return "video/mp4";
        }
        if (".mp3".equalsIgnoreCase(FilenameExtension)) {
            return "audio/mp3";
        }
        return "text/html";
    }


    /**
     * @Description: 根据文件路径获取InputStream流
     */
    public InputStream getInputStreamByFileUrl(String fileName) {
        // ossObject包含文件所在的存储空间名称、文件名称、文件元信息以及一个输入流。
        OSSObject ossObject = ossClient.getObject(bucketName, fileName);
        return ossObject.getObjectContent();
    }
}

第三步：上传下载文件

public class FlightFileController {

    @ResponseBody
    @PostMapping("/upload")
    public Response upload(@RequestParam("file") MultipartFile file) {
        String filename = file.getResource().getFilename();
        //文件名
        String pattern = "yyyy-MM-dd";
        String dir = DateFormatUtils.format(new Date(), pattern);
        String name = "";
        if (getFileType(filename) == 0) {
            name = OssBucketEnum.VIDEO.getValue() + "/" + dir + "/" + filename;
        } else {
            name = OssBucketEnum.PICTURE.getValue() + "/" + dir + "/" + filename;
        }
        InputStream inputStream = null;
        try {
            inputStream = file.getInputStream();
        } catch (IOException e) {
            e.printStackTrace();
            log.info("上传失败");
        }
        AliOssCloudUtil util = new AliOssCloudUtil();
        //上传成功返回可直接查看文件的url
        String url = util.uploadFile2OSS(inputStream, name);
        return Response.success(url);
    }

    public int getFileType(String fileName) {
        int i = 0;
        FileNameMap fileNameMap = URLConnection.getFileNameMap();
        String contentTypeFor = fileNameMap.getContentTypeFor(fileName);
        //下面是进一判断是视频和图片的区别
        if (contentTypeFor != null) {// 当为图片时不为空，是视频时为空
            i = 1;
        }
        return i;
    }

    @PostMapping("/downLoad")
    public void downloadFile(String fileName, HttpServletResponse response) {
        try {
            AliOssCloudUtil ossClientUtil = new AliOssCloudUtil();
            InputStream is = ossClientUtil.getInputStreamByFileUrl(ossClientUtil.getFiledir() + fileName);
            // 配置文件下载
            response.setHeader("content-type", "application/octet-stream");
            response.setContentType("application/octet-stream");
            // 下载文件能正常显示中文
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            OutputStream os = response.getOutputStream();
            byte[] b = new byte[1024];
            int len = -1;
            while ((len = is.read(b)) != -1) {
                os.write(b, 0, len);
            }
            is.close();
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}