aliyun-Oss的介紹與使用

接上文aliyun-oss-01

1 Oss基于Java的使用（Java-SDK）

1.1 maven中引入

<!-- https://mvnrepository.com/artifact/com.aliyun.oss/aliyun-sdk-oss -->
<dependency>
    <groupId>com.aliyun.oss</groupId>
    <artifactId>aliyun-sdk-oss</artifactId>
    <version>3.11.3</version>
</dependency>

1.1.1 如果是java9 及以上的版本則需要引入jaxb相關依賴，添加jaxb相關依賴示例代碼如下：

<dependency>
    <groupId>javax.xml.bind</groupId>
    <artifactId>jaxb-api</artifactId>
    <version>2.3.1</version>
</dependency>
<dependency>
    <groupId>javax.activation</groupId>
    <artifactId>activation</artifactId>
    <version>1.1.1</version>
</dependency>
<!-- no more than 2.3.3-->
<dependency>
    <groupId>org.glassfish.jaxb</groupId>
    <artifactId>jaxb-runtime</artifactId>
    <version>2.3.3</version>
</dependency>

1.2 OssClient使用

OSSClient是OSS的Java客戶端，用于管理存盤空間和檔案等OSS資源，使用Java SDK發起OSS請求，您需要初始化一個OSSClient實體，并根據需要修改ClientConfiguration的默認配置項，

1.2.1所需引數

@Value("${oss.endpoint}")
    private String endpoint;

    @Value("${oss.AccessKeyID}")
    private String accessKeyID;

    @Value("${oss.AccessKeySecret}")
    private String accessKeySecret;

    @Value("$oss.bucketName")
    private String bucketName;

1.2.2新建OSSClient

這的Oss 用完之后 是需要關閉的，如果不關閉，會造成記憶體泄露

/**
     * 使用OSS域名新建OSSClient（其中之一）
     *
     * @return OssClient
     */
    public OSS ossClientCreate() {
        final OSS build = new OSSClientBuilder().build(endpoint, accessKeyID, accessKeySecret);
        log.info("OSSClient 新建成功");
        return build;
    }

1.2.3創建一個bucket

創建bucket時，bucket的名字一定要是沒有被別人和自己取過的

他人存在的bucketName,則會出現以下資訊

[ErrorCode]: AccessDenied
[RequestId]: xxxxxxx
[HostId]: image.oss-cn-shanghai.aliyuncs.com
[ResponseError]:
<?xml version="1.0" encoding="UTF-8"?>
<Error>
  <Code>AccessDenied</Code>
  <Message>The bucket you are attempting to access must be addressed using the specified endpoint. Please send all future requests to this endpoint.</Message>
  <RequestId>xxxxxxxxx</RequestId>
  <HostId>image.oss-cn-shanghai.aliyuncs.com</HostId>
  <Bucket>image</Bucket>
  <Endpoint>oss-cn-hangzhou.aliyuncs.com</Endpoint>
</Error>

自己存在的bucketNam

[ErrorCode]: BucketAlreadyExists
[RequestId]: xxxxxxxxx
[HostId]: data-lujy.oss-cn-shanghai.aliyuncs.com
[ResponseError]:
<?xml version="1.0" encoding="UTF-8"?>
<Error>
  <Code>BucketAlreadyExists</Code>
  <Message>The requested bucket name is not available. The bucket namespace is shared by all users of the system. Please select a different name and try again.</Message>
  <RequestId>xxxxxxxxxxx</RequestId>
  <HostId>data-lujy.oss-cn-shanghai.aliyuncs.com</HostId>
  <BucketName>data-lujy</BucketName>
</Error>

tip:這兩者的區別在于，第一個相當于去訪問一個bucket但是密碼和賬戶錯了，從而導致了拒絕訪問，第二個則是賬戶和密碼正確，成功訪問了，當時在創建的時候，出現了相同bucket，

    /**
     * 創建一個bucket
     *
     * @param oss        OSSClient
     * @param bucketName 桶的名稱
     */
    public Bucket createBucket(OSS oss, String bucketName) {
        final boolean b = oss.doesBucketExist(bucketName);
        if (b) {
            log.warn("該名稱已存在：{}", bucketName);
            return null;
        } else {
            return oss.createBucket(bucketName);
        }
    }

1.2.4 上傳檔案

oss的上傳檔案方式很多，這里只是采用了比較簡單的一種

/**
     * 簡單上傳檔案
     * @param oss         OssClient
     * @param objectName  保存為指定的路徑名稱 需全路徑如 image/day01/xxx.txt
     * @param inputStream 檔案流
     * @return
     */
    public Boolean uploadFile(OSS oss, String objectName, InputStream inputStream) {
        try {
            final PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, objectName, inputStream);
            //上傳檔案
            final PutObjectResult putObjectResult = oss.putObject(putObjectRequest);
            return putObjectResult != null;
        } catch (OSSException | ClientException e) {
            e.printStackTrace();
            return false;
        }
    }

1.2.5 下載檔案

流下載

/**
     * 流下載
     *
     * @param oss
     * @param objectName
     * @return
     */
    public void downloadFileStream(OSS oss, String objectName) {
        final OSSObject object = oss.getObject(bucketName, objectName);
        final String key = object.getKey();
        System.out.println(key);
        try (
                InputStream is = object.getObjectContent();
                OutputStream os = new FileOutputStream(new File("src/main/resources/static/" + objectName));
        ) {
            //創建快取區
            byte[] bytes = new byte[2048];
            int length;
            while ((length = is.read(bytes)) != -1) {
                os.write(bytes, 0, length);
            }
            log.info("全部寫入快取區");
            os.flush();
        } catch (Exception e) {
            e.printStackTrace();
            log.error("流讀取出現錯誤：{}", e.getMessage());
        }
    }

本地下載

/**
     * 下載到本地
     *
     * @param oss        OssClient
     * @param objectName oss 中的檔案地址
     * @param localFile  本地檔案地址 如果存在 則會直接覆寫不會新建
     */
    public Boolean downloadFileLocal(OSS oss, String objectName, File localFile) {
        final ObjectMetadata omd;
        try {
            final GetObjectRequest getObjectRequest = new GetObjectRequest(bucketName, objectName);
            omd = oss.getObject(getObjectRequest, localFile);
            if (omd == null) {
                log.info("本地檔案下載失敗，原因：ObjectMetadata 為空");
                return false;
            } else {
                log.info("下載成功");
                return true;
            }
        } catch (OSSException | ClientException e) {
            e.printStackTrace();
            log.info("下載出現例外：{}", e.getMessage());
            return false;
        }
    }

// TODO: 2021/2/9 范圍下載(未完成)
// TODO: 2021/2/9 斷電續傳下載(未完成)
// TODO: 2021/2/9 限定條件下載(未完成)