Amazon AWS S3 上传文件 并获取公用url

      最近在用aws的s3做云存储，把文件上传上去，在数据库中记录对应的url，下面是示例代码：

 

    public static String uploadToS3(File tempFile, String remoteFileName) throws IOException {
        PropertiesUtil propertiesUtil = new PropertiesUtil("");
        //首先创建一个s3的客户端操作对象（需要amazon提供的密钥）
        AmazonS3 s3 = new AmazonS3Client(
                new BasicAWSCredentials((Consts.S3_ACCESS_KEY),
                        (Consts.S3_SCERET_KEY)));
        Region usWest2 = (Regions.US_WEST_2);
        (usWest2);
        //设置bucket,key
        String bucketName = Consts.S3_BUCKET_NAME;
        String key = () + ".apk";
        try {
            //验证名称为bucketName的bucket是否存在，不存在则创建
            if (!checkBucketExists(s3, bucketName)) {
                (bucketName);
            }
            //上传文件
            (new PutObjectRequest(bucketName, key, tempFile));
            S3Object object = (new GetObjectRequest(bucketName, key));
            //获取一个request
            GeneratePresignedUrlRequest urlRequest = new GeneratePresignedUrlRequest(
                    bucketName, key);
            Date expirationDate = null;
            try {
                expirationDate = new SimpleDateFormat("yyyy-MM-dd").parse("2020-12-31");
            } catch (Exception e) {
                ();
            }
            //设置过期时间
            (expirationDate);
            //生成公用的url
            URL url = (urlRequest);
            ("=========URL=================" + url + "============URL=============");
            if (url == null) {
                throw new OperateFailureException("can't get s3 file url!");
            }
            return ();
        } catch (AmazonServiceException ase) {
            ();
            ("====================================AWS S3 UPLOAD ERROR START======================================");
            ("Caught an AmazonServiceException, which means your request made it "
                    + "to Amazon S3, but was rejected with an error response for some reason.");
            ("Caught an AmazonServiceException, which means your request made it "
                    + "to Amazon S3, but was rejected with an error response for some reason.");
            ("Error Message:    " + ());
            ("HTTP Status Code: " + ());
            ("AWS Error Code:   " + ());
            ("Error Type:       " + ());
            ("Request ID:       " + ());
            ((), ase);
            ("====================================AWS S3 UPLOAD ERROR END======================================");
            throw new OperateFailureException("error occurs during upload to s3!");
        } catch (AmazonClientException ace) {
            ("====================================AWS S3 UPLOAD ERROR START======================================");
            ("Caught an AmazonClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with S3, "
                    + "such as not being able to access the network.");
            ("Error Message: " + ());
            ("====================================AWS S3 UPLOAD ERROR END======================================");
            throw new OperateFailureException("error occurs during upload to s3!");
        }
    }

    /**
     * 验证s3上是否存在名称为bucketName的Bucket
     * @param s3
     * @param bucketName
     * @return
     */
    public static boolean checkBucketExists (AmazonS3 s3, String bucketName) {
        List<Bucket> buckets = ();
        for (Bucket bucket : buckets) {
            if (((), bucketName)) {
                return true;
            }
        }
        return false;
    }

 上面的代码只是一部分，整个过程是在jsp页面吧文件上传到后台，后台创建一个临时文件，把临时文件上传到s3上，并获取一个可以下载文件的url；

 

这里是一个英文的参考：/docs/master/radosgw/s3/java/