Verificación de datos (OSS SDK for Java 1.0) - Object Storage Service

OSS SDK for Java utiliza la verificación MD5 y CRC-64 para garantizar la integridad de los datos durante la carga, descarga y copia de objetos.

Notas de uso

En este tema se utiliza el endpoint público de la región China (Hangzhou). Si necesita acceder a OSS desde otros servicios de Alibaba Cloud en la misma región, utilice un endpoint interno. Para obtener más información sobre las regiones y los endpoints compatibles, consulte Regions and endpoints.
Las credenciales de acceso de este tema se obtienen de variables de entorno. Para obtener más información, consulte 配置访问凭证.
Este tema muestra cómo crear una instancia de OSSClient con un endpoint de OSS. Para conocer configuraciones alternativas, como usar un dominio personalizado o autenticarse con credenciales de Security Token Service (STS), consulte Client configuration.

Verificación MD5

Cuando se incluye Content-MD5 en una solicitud de carga, OSS compara el hash MD5 de los datos recibidos con el valor proporcionado. Si no coinciden, OSS devuelve un error InvalidDigest y debe volver a cargar el objeto.

La carga multiparte también admite la verificación MD5. Llame al método setMd5Digest en UploadPartRequest para establecer el hash MD5 de cada parte.

Nota

La verificación MD5 es compatible con PutObject, GetObject, AppendObject, PostObject, la carga multiparte y UploadPart.

Configure la verificación MD5 en una operación PutObject:

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.common.utils.BinaryUtil;
import com.aliyun.oss.model.ObjectMetadata;
import java.io.ByteArrayInputStream;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Do not include the bucket name in the full path. 
        String objectName = "exampledir/object";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // Call the shutdown method to release resources when the OSSClient is no longer in use. 
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // Upload the string. 
            String content = "Hello OSS";

            ObjectMetadata meta = new ObjectMetadata();
            // Configure MD5 verification. 
            String md5 = BinaryUtil.toBase64String(BinaryUtil.calculateMd5(content.getBytes()));
            meta.setContentMD5(md5);

            ossClient.putObject(bucketName, objectName, new ByteArrayInputStream(content.getBytes()), meta);

        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

Configure la verificación MD5 en una operación de carga multiparte:

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import com.aliyun.oss.ClientBuilderConfiguration;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.common.utils.BinaryUtil;
import com.aliyun.oss.model.CompleteMultipartUploadRequest;
import com.aliyun.oss.model.CompleteMultipartUploadResult;
import com.aliyun.oss.model.InitiateMultipartUploadRequest;
import com.aliyun.oss.model.InitiateMultipartUploadResult;
import com.aliyun.oss.model.PartETag;
import com.aliyun.oss.model.UploadPartRequest;
import com.aliyun.oss.model.UploadPartResult;

public class Demo {
    public static void main(String[] args) throws Exception {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "http://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket.   
        String bucketName = "examplebucket";
        // Specify the full path of the object. Do not include the bucket name in the full path. 
        String objectName = "exampledir/object";
        // Specify the path of the local file that you want to upload. 
        String localFile = "D:\\localpath\\examplefile.txt";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance. 
        // Call the shutdown method to release resources when the OSSClient is no longer in use.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();
        // Create an InitiateMultipartUploadRequest object. 
        InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(bucketName, objectName);
        // Optional. Specify the storage class.
        // ObjectMetadata metadata = new ObjectMetadata();
        // metadata.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard.toString());
        // request.setObjectMetadata(metadata);
        // Initiate a multipart upload task. 
        InitiateMultipartUploadResult upresult = ossClient.initiateMultipartUpload(request);
        // Obtain an upload ID. The upload ID uniquely identifies the multipart upload task. You can use the upload ID to initiate related requests such as canceling and querying a multipart upload task. 
        String uploadId = upresult.getUploadId();
        // partETags is a set of PartETags. The PartETag of a part consists of the part number and ETag value of the part. 
        List<PartETag> partETags = new ArrayList<PartETag>();
        // Calculate the total number of parts to upload. 
        final long partSize = 1 * 1024 * 1024L;   // 1MB
        final File sampleFile = new File(localFile);
        long fileLength = sampleFile.length();
        int partCount = (int) (fileLength / partSize);
        if (fileLength % partSize != 0) {
            partCount++;
        }
        // Upload all parts. 
        for (int i = 0; i < partCount; i++) {
            long startPos = i * partSize;
            long curPartSize = (i + 1 == partCount) ? (fileLength - startPos) : partSize;
            InputStream instream = new FileInputStream(sampleFile);
            InputStream instream1 = new FileInputStream(sampleFile);
         // Skip parts that have been uploaded. 
            instream.skip(startPos);
            instream1.skip(startPos);
            String md5;
            if(i==partCount-1){
         // The size of the last part is not necessarily equal to the specified part size.
                md5 = md5(instream1,fileLength - startPos);
            }else{
                md5 = md5(instream1,partSize);
            }
          // instream1.skip(n)
            UploadPartRequest uploadPartRequest = new UploadPartRequest();
            uploadPartRequest.setBucketName(bucketName);
            uploadPartRequest.setKey(objectName);
            uploadPartRequest.setUploadId(uploadId);
            uploadPartRequest.setInputStream(instream);
            uploadPartRequest.setMd5Digest(md5);
         // Specify the part size. Each part except the last part must be equal to or greater than 100 KB. 
            uploadPartRequest.setPartSize(curPartSize);
         // Configure part numbers. Each part is configured with a part number. The value ranges from 1 to 10000. If you configure a number beyond the range, OSS returns an InvalidArgument error code. 
            uploadPartRequest.setPartNumber( i + 1);
         // Parts are not necessarily uploaded in order and can be uploaded from different OSS clients. OSS sorts the parts based on the part numbers and combines the parts into a complete object. 
            UploadPartResult uploadPartResult = ossClient.uploadPart(uploadPartRequest);
         // System.out.println("server md5" +uploadPartResult.getETag());
         // Each time a part is uploaded, OSS returns a result that contains a PartETag. The PartETag is stored in partETags. 
            partETags.add(uploadPartResult.getPartETag());
        }
        // Create a CompleteMultipartUploadRequest object. 
        // When you call the CompleteMultipartUpload operation, you must provide all valid PartETags. After OSS receives the partETags, OSS verifies all parts one by one. After part verification is successful, OSS combines these parts into a complete object. 
        CompleteMultipartUploadRequest completeMultipartUploadRequest =
                new CompleteMultipartUploadRequest(bucketName, objectName, uploadId, partETags);
        // Optional. Set the access control list (ACL) of the object. 
        // completeMultipartUploadRequest.setObjectACL(CannedAccessControlList.PublicRead);
        // Complete the multipart upload task. 
        CompleteMultipartUploadResult completeMultipartUploadResult = ossClient.completeMultipartUpload(completeMultipartUploadRequest);
        // Close your OSSClient. 
        ossClient.shutdown();
    }
    public static String md5(InputStream in , long length1) throws Exception{
        byte[] bytes = new byte[(int) length1];
        long length_tmp = length1;
        int readSize = in.read(bytes, (int) 0, (int) length_tmp);
        return BinaryUtil.toBase64String(BinaryUtil.calculateMd5(bytes));
    }
}

Verificación CRC-64

La verificación CRC-64 está habilitada de forma predeterminada en las operaciones de carga, descarga y copia de objetos.

Nota

CRC-64 aplica a PutObject, GetObject, AppendObject y UploadPart, y está habilitado de forma predeterminada. Si la suma de comprobación CRC-64 del cliente difiere de la del servidor, se lanza un error InconsistentException.
No se admite CRC-64 en las descargas por rangos.
El uso de CRC-64 incrementa el consumo de CPU y reduce la velocidad de carga y descarga.

CRC-64 para la descarga de objetos

Ejecute la verificación CRC-64 durante la descarga de un objeto:

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.common.utils.IOUtils;
import com.aliyun.oss.internal.OSSHeaders;
import com.aliyun.oss.internal.OSSUtils;
import com.aliyun.oss.model.GetObjectRequest;
import com.aliyun.oss.model.OSSObject;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Do not include the bucket name in the full path. 
        String objectName = "exampledir/object";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // Call the shutdown method to release resources when the OSSClient is no longer in use. 
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // Download the object in streaming mode. 
            GetObjectRequest getObjectRequest = new GetObjectRequest(bucketName, objectName);
            OSSObject ossObject = ossClient.getObject(bucketName, objectName);

            // Read the object from the stream to obtain clientCRC. 
            System.out.println("Object content:");
            BufferedReader reader = new BufferedReader(new InputStreamReader(ossObject.getObjectContent()));
            while (true) {
                String line = reader.readLine();
                if (line == null) break;

                System.out.println("\n" + line);
            }
            // You must close the obtained stream after the object is read. Otherwise, connection leaks may occur. Consequently, no connections are available and an exception occurs. 
            reader.close();

            // Check whether CRC-64 is enabled on the client. By default, CRC-64 is enabled on the client. 
            Boolean isCrcCheckEnabled = ((OSSClient)ossClient).getClientConfiguration().isCrcCheckEnabled();
            // Check whether the download quest is a range download request. CRC-64 verification is not supported for range download. 
            Boolean isRangGetRequest = getObjectRequest.getHeaders().get(OSSHeaders.RANGE) != null;

            // Check whether the CRC-64 value in the returned result is the same as that of the downloaded object. 
            if (isCrcCheckEnabled && !isRangGetRequest) {
                Long clientCRC = IOUtils.getCRCValue(ossObject.getObjectContent());
                OSSUtils.checkChecksum(clientCRC, ossObject.getServerCRC(), ossObject.getRequestId());
            }
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

CRC-64 para la carga por anexión

Ejecute la verificación CRC-64 durante una carga por anexión:

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
import java.io.ByteArrayInputStream;

public class Demo {
    public static void main(String[] args) throws Exception {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampleobject.txt. Do not include the bucket name in the full path. 
        String objectName = "exampleobject.txt";
        // Enter the content of the first append upload, such as Hello. 
        String firstAppendContent = "Hello";
        // Enter the content of the second append upload, such as World. 
        String secondAppendContent = "World";
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance. 
        // Call the shutdown method to release resources when the OSSClient is no longer in use.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // Perform the first append operation. 
            AppendObjectRequest appendObjectRequest = new AppendObjectRequest(bucketName, objectName, new ByteArrayInputStream(firstAppendContent.getBytes()));
            appendObjectRequest.setPosition(0L);
            // Set the initial CRC-64 value. OSS SDK for Java performs CRC-64 on the uploaded content by default. 
            appendObjectRequest.setInitCRC(0L);
            AppendObjectResult appendObjectResult = ossClient.appendObject(appendObjectRequest);

            // Perform the second append upload operation. 
            appendObjectRequest = new AppendObjectRequest(bucketName, objectName, new ByteArrayInputStream(secondAppendContent.getBytes()));
            appendObjectRequest.setPosition(appendObjectResult.getNextPosition());
            // Set the CRC-64 value to that of the uploaded object. OSS SDK for Java performs CRC-64 on the uploaded content by default. 
            appendObjectRequest.setInitCRC(appendObjectResult.getClientCRC());
            ossClient.appendObject(appendObjectRequest);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

Referencias

El código de ejemplo completo para la verificación MD5 y CRC-64 está disponible en GitHub.