<groupId>com.qcloud</groupId>
       <artifactId>cos_api-bundle</artifactId>
<version>5.6.35</version>

<groupId>org.apache.httpcomponents</groupId>
       <artifactId>httpclient</artifactId>
 <version>4.5.3</version> 

<groupId>com.qcloud</groupId>
       <artifactId>cos_api-bundle</artifactId>
<version>5.6.35</version>

<groupId>com.qcloud</groupId>
       <artifactId>cos_api-bundle</artifactId>
<version>5.6.35</version>

String bucketName = "examplebucket-1250000000";
String key = "folder/images/";
// 目录对象即是一个/结尾的空文件，上传一个长度为 0 的 byte 流
InputStream input = new ByteArrayInputStream(new byte[0]);
ObjectMetadata objectMetadata = new ObjectMetadata();
objectMetadata.setContentLength(0);

PutObjectRequest putObjectRequest =
new PutObjectRequest(bucketName, key, input, objectMetadata);
PutObjectResult putObjectResult = cosClient.putObject(putObjectRequest);

// 初始化用户身份信息(secretId, secretKey)
String secretId = "COS_SECRETID";
String secretKey = "COS_SECRETKEY";
COSCredentials cred = new BasicCOSCredentials(secretId, secretKey);
// 设置 bucket 的区域, COS 地域的简称请参照 https://www.tencentcloud.com/document/product/436/6224
ClientConfig clientConfig = new ClientConfig(new Region("ap-beijing-1"));
// 配置使用 https
clientConfig.setHttpProtocol(HttpProtocol.https);
// 生成 cos 客户端
COSClient cosClient = new COSClient(cred, clientConfig);

// 初始化用户身份信息(secretId, secretKey)
String secretId = "COS_SECRETID";
String secretKey = "COS_SECRETKEY";
COSCredentials cred = new BasicCOSCredentials(secretId, secretKey);
// 设置 bucket 的区域, COS 地域的简称请参照 https://www.tencentcloud.com/document/product/436/6224
ClientConfig clientConfig = new ClientConfig(new Region("ap-beijing-1"));
// 配置使用代理(IP 和端口需要同时设置)
// 设置代理 IP (也可传入域名)
clientConfig.setHttpProxyIp("192.168.2.3");
// 设置代理端口
clientConfig.setHttpProxyPort(8080);
// 生成 cos 客户端
COSClient cosClient = new COSClient(cred, clientConfig);

// 步骤1：实现 EndpointBuilder 接口中的两个函数
class SelfDefinedEndpointBuilder implements EndpointBuilder {
    @Override
    public String buildGeneralApiEndpoint(String bucketName) {
        return String.format("%s.%s", bucketName, "mytest.com");
    }

    @Override
    public String buildGetServiceApiEndpoint() {
        return "service.mytest.com";
    }
}

// 步骤2：初始化客户端
String secretId = "COS_SECRETID";
String secretKey = "COS_SECRETKEY";
COSCredentials cred = new BasicCOSCredentials(secretId, secretKey);
SelfDefinedEndpointBuilder selfDefinedEndpointBuilder = new SelfDefinedEndpointBuilder();
ClientConfig clientConfig = new ClientConfig(new Region("ap-beijing"));
clientConfig .setEndpointBuilder(selfDefinedEndpointBuilder);
COSClient cosClient = new COSClient(cred, clientConfig);

CRC64 localCRC = new CRC64();
// 计算本地的 crc64
localCRC.update();
//...

// 把 COS 返回的 CRC 变成 Long
cosCRC = crc64ToLong(strCOSCRC);

// 比较
if (cosCRC == localCRC.getValue()) {
   xxx
}

// 用来将 COS 返回的 CRC64 转化成 1 个 Java 里的 Long
long crc64ToLong(String crc64) {
   if (crc64.charAt(0) == '-') {
       return negativeCrc64ToLong(crc64);
   } else {
       return positiveCrc64ToLong(crc64);
   }
}

long positiveCrc64ToLong(String strCrc64) {
   BigInteger crc64 = new BigInteger(strCrc64);
   BigInteger maxLong = new BigInteger(Long.toString(Long.MAX_VALUE));

   int maxCnt = 0;

   while (crc64.compareTo(maxLong) > 0) {
       crc64 = crc64.subtract(maxLong);
       maxCnt++;
   }

   return crc64.longValue() + Long.MAX_VALUE * maxCnt;
}

long negativeCrc64ToLong(String strCrc64) {
   BigInteger crc64 = new BigInteger(strCrc64);
   BigInteger minLong = new BigInteger(Long.toString(Long.MIN_VALUE));

   int minCnt = 0;

   while (crc64.compareTo(minLong) < 0) {
       crc64 = crc64.subtract(minLong);
       minCnt++;
   }

   return crc64.longValue() + Long.MIN_VALUE * minCnt;
}