Como processar imagens usando o OSS SDK for Java - Object Storage Service: Central de Documentação do Alibaba Cloud

O Image Processing (IMG) é um serviço de processamento de imagens seguro, econômico e altamente confiável do Object Storage Service (OSS). Após carregar as imagens originais no OSS, chame operações da API RESTful para processá-las a qualquer momento, em qualquer lugar e em qualquer dispositivo conectado.

Observações de uso

Este tópico utiliza o endpoint público da região China (Hangzhou). Para acessar o OSS a partir de outros serviços da Alibaba Cloud na mesma região, utilize um endpoint interno. Para obter detalhes sobre as regiões e endpoints compatíveis, consulte Regiões e endpoints.
As credenciais de acesso neste tópico são obtidas de variáveis de ambiente. Para mais informações, consulte Configurar credenciais de acesso.
Este tópico demonstra como criar uma instância OSSClient com um endpoint do OSS. Para configurações alternativas, como uso de domínio personalizado ou autenticação com credenciais do Security Token Service (STS), consulte Configuração do cliente.

Usar parâmetros IMG para processar imagens

Usar um único parâmetro IMG para processar uma imagem

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

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 = "exampleobject.jpg";
        // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-resize.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, the processed image is saved in the path. 
        String localPath = "D:\\localpath\\example-resize.jpg";
        // 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 {
            // Resize the image to a height and width of 100 pixels. 
            String style = "image/resize,m_fixed,w_100,h_100";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-resize.jpg and save the image to your local computer. 
            // If you specify only the name of a local file such as example-resize.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File(localPath));
        } 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();
            }
        }
    }
}

Usar diferentes parâmetros IMG para processar uma imagem

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

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 = "exampleobject.jpg";
        // 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 {
            // Resize the image to a height and width of 100 pixels. 
            String style = "image/resize,m_fixed,w_100,h_100";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-resize.jpg and save the image to your local computer. 
            // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-resize.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, the processed image is saved in the path. 
            // If you specify only the name of a local file such as example-resize.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File("D:\\localpath\\example-resize.jpg"));

            // Crop the image to a height and width of 100 pixels by setting the coordinate pair to (100, 100). 
            style = "image/crop,w_100,h_100,x_100,y_100";
            request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-crop.jpg and save the image to your local computer. 
            ossClient.getObject(request, new File("D:\\localpath\\example-crop.jpg"));

            // Rotate the image 90 degrees. 
            style = "image/rotate,90";
            request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-rotate.jpg and save the image to your local computer. 
            ossClient.getObject(request, new File("D:\\localpath\\example-rotate.jpg"));

            // Add a text watermark to the image. 
            // After the text watermark content is encoded in Base64, replace plus signs (+) in the encoded result with hyphens (-) and forward slashes (/) with underscores (_), and remove equal signs (=) at the end. Then, you can obtain the watermark string. 
            // Specify Hello World as the content of the text watermark, and encode the text content. Then, you can obtain the SGVsbG8gV29ybGQ string. 
            style = "image/watermark,text_SGVsbG8gV29ybGQ";
            request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-watermarktext.jpg and save the image to your local computer. 
            ossClient.getObject(request, new File("D:\\localpath\\example-watermarktext.jpg"));

            // Add an image watermark to the image. Make sure that the watermark image is stored in the bucket that stores the source image. 
            // After the full path of the watermark image is encoded in Base64, replace plus signs (+) in the encoded result with hyphens (-) and forward slashes (/) with underscores (_), and remove equal signs (=) at the end. Then, you can obtain the watermark string. 
            // Specify panda.jpg as the full path of the watermark image, and encode the full path. Then, you can obtain the cGFuZGEuanBn string. 
            style = "image/watermark,image_cGFuZGEuanBn";
            request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-watermarkimage.jpg and save the image to your local computer. 
            ossClient.getObject(request, new File("D:\\localpath\\example-watermarkimage.jpg"));
        } 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();
             }
        }
    }
}

Usar múltiplos parâmetros IMG para processar uma imagem simultaneamente

O código de exemplo a seguir mostra como utilizar vários parâmetros IMG para processar uma imagem ao mesmo tempo. Separe os parâmetros IMG com barras (/).

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

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 = "exampleobject.jpg";
        // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-new.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, the processed image is saved in the path. 
        String pathName = "D:\\localpath\\example-new.jpg";
        // 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 {
            // Resize the image to a height and width of 100 pixels, and rotate the image 90 degrees. 
            String style = "image/resize,m_fixed,w_100,h_100/rotate,90";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-new.jpg and save the image to your local computer. 
            // If you specify only the name of a local file such as example-new.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File("D:\\localpath\\example-new.jpg"));
        } 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();
            }
        }
    }
}

Usar um estilo de imagem para processar uma imagem

Crie um estilo de imagem no console do OSS e encapsule diversos parâmetros IMG nesse estilo. Em seguida, utilize o estilo para processar as imagens. Para mais informações, consulte Estilos de imagem.

O código de exemplo abaixo ilustra como aplicar um estilo de imagem no processamento:

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

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 = "exampleobject.jpg";
        // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-new.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, the processed image is saved in the path. 
        String pathName = "D:\\localpath\\example-new.jpg";
        // 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 {
            // Use a custom image style to process the image. 
            // In this example, replace yourCustomStyleName with the name of the image style that you created in the OSS console. 
            String style = "style/yourCustomStyleName";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-new.jpg and save the image to your local computer. 
            // If you specify only the name of a local file such as example-new.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File(pathName));
        } 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();
            }
        }
    }
}

Salvar imagens processadas

Por padrão, o IMG não salva as imagens processadas. Chame a operação ImgSaveAs para salvar as imagens no bucket onde as imagens originais estão armazenadas.

O exemplo de código a seguir demonstra como salvar uma imagem processada:

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.common.utils.IOUtils;
import com.aliyun.oss.model.GenericResult;
import com.aliyun.oss.model.ProcessObjectRequest;
import java.util.Formatter;

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 sourceImage = "exampleimage.png";
        // 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 {
            // Resize the image to a height and width of 100 pixels. 
            StringBuilder sbStyle = new StringBuilder();
            Formatter styleFormatter = new Formatter(sbStyle);
            String styleType = "image/resize,m_fixed,w_100,h_100";
            // Name the processed image example-resize.png and save the image to the bucket in which the source image is stored. 
            // Specify the full path of the object. Do not include the bucket name in the full path. 
            String targetImage = "example-resize.png";
            styleFormatter.format("%s|sys/saveas,o_%s,b_%s", styleType,
                    BinaryUtil.toBase64String(targetImage.getBytes()),
                    BinaryUtil.toBase64String(bucketName.getBytes()));
            System.out.println(sbStyle.toString());
            ProcessObjectRequest request = new ProcessObjectRequest(bucketName, sourceImage, sbStyle.toString());
            GenericResult processResult = ossClient.processObject(request);
            String json = IOUtils.readStreamAsString(processResult.getResponse().getContent(), "UTF-8");
            processResult.getResponse().getContent().close();
            System.out.println(json);
        } 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();
            }
        }
    }
}

Gerar uma URL de objeto assinada que inclui parâmetros IMG

URLs de objetos privados devem ser assinadas. Não é possível adicionar parâmetros IMG ao final de uma URL assinada. Caso precise processar um objeto privado, adicione os parâmetros IMG à assinatura. O código abaixo exemplifica como incluir parâmetros IMG na assinatura:

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.GeneratePresignedUrlRequest;
import java.net.URL;
import java.util.Date;

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 = "exampleobject.jpg";
        // 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 {
            // Resize the image to a height and width of 100 pixels, and rotate the image 90 degrees. 
            String style = "image/resize,m_fixed,w_100,h_100/rotate,90";
            // Set the validity period of the signed URL to 10 minutes. (The maximum validity period is 32400 seconds.)
            Date expiration = new Date(new Date().getTime() + 1000 * 60 * 10 );
            GeneratePresignedUrlRequest req = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.GET);
            req.setExpiration(expiration);
            req.setProcess(style);
            URL signedUrl = ossClient.generatePresignedUrl(req);
            System.out.println(signedUrl);
        } 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();
            }
        }
    }
}

Referências

Para mais detalhes sobre os parâmetros IMG compatíveis, consulte Visão geral.
Acesse o código de exemplo completo para IMG no GitHub.