IMG

Usage notes

• In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions, endpoints and open ports.

• In this topic, access credentials are obtained from environment variables. For more information about how to configure access credentials, see Configure access credentials.

• In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.

Use IMG parameters to process images

• Use a single IMG parameter to process an image

  import com.aliyun.oss.*;
  import com.aliyun.oss.common.auth.*;
  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. 
          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();
              }
          }
      }
  }

• Use different IMG parameters to process an image

  import com.aliyun.oss.*;
  import com.aliyun.oss.common.auth.*;
  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. 
          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();
               }
          }
      }
  }

• Use multiple IMG parameters to process an image at the same time

  The following sample code provides an example on how to use multiple IMG parameters to process an image at the same time. Separate the IMG parameters with forward slashes (/).

  import com.aliyun.oss.*;
  import com.aliyun.oss.common.auth.*;
  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. 
          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();
              }
          }
      }
  }

Use an image style to process an image

You can create an image style in the OSS console and encapsulate multiple IMG parameters in the style. Then, you can use the style to process images. For more information, see Image styles.

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
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. 
        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();
            }
        }
    }
}

Save processed images

By default, IMG does not save processed images. You can call the ImgSaveAs operation to save the images to the bucket in which the source images are stored.

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
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. 
        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();
            }
        }
    }
}

Generate a signed object URL that includes IMG parameters

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
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. 
        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();
            }
        }
    }
}

References

• For more information about supported IMG parameters, see Overview.

• For the complete sample code for IMG, visit GitHub.