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Overview

This document provides an overview of APIs and SDK code samples related to object content extraction.

SDK API References

For the parameters and method descriptions of all the APIs in the SDK, see SDK API Reference.

Extracting Object Content

Description

COS Select supports extracting content from objects in the following formats:

• CSV: The object’s data records are separated by a specific delimiter.
• JSON: either a JSON file or a JSON list

Note：

• To use COS Select, you must have the permission on cos:GetObject.
• CSV and JSON objects need to be encoded in UTF-8.
• COS Select supports extracting CSV and JSON objects compressed by gzip or bzip2.
• COS Select supports extracting CSV and JSON objects encrypted with SSE-COS.

Sample code

String bucket = "examplebucket-1250000000";
// The object must be in JSON or CSV format
String cosPath = "exampleobject";
final String expression = "Select * from COSObject";
SelectObjectContentRequest selectObjectContentRequest = new SelectObjectContentRequest(
       bucket, cosPath, expression, true,
       new InputSerialization(CompressionType.NONE, new JSONInput(JSONType.DOCUMENT)),
       new OutputSerialization(new JSONOutput(","))
);
// Set the result callback which may work repeatedly
selectObjectContentRequest.setSelectObjectContentProgressListener(new SelectObjectContentListener() {
   @Override
   public void onProcess(SelectObjectContentEvent event) {
    }
});
cosXmlService.selectObjectContentAsync(selectObjectContentRequest,
       new CosXmlResultListener() {
   @Override
   public void onSuccess(CosXmlRequest request, CosXmlResult result) {
       SelectObjectContentResult selectObjectContentResult =
               (SelectObjectContentResult) result;
   }
    // If you use the Kotlin language to call this, please note that the exception in the callback method is nullable; otherwise, the onFail method will not be called back, that is:
   // clientException is of type CosXmlClientException? and serviceException is of type CosXmlServiceException?
   @Override
   public void onFail(CosXmlRequest cosXmlRequest,
                      @Nullable CosXmlClientException clientException,
                      @Nullable CosXmlServiceException serviceException) {
       if (clientException != null) {
           clientException.printStackTrace();
       } else {
           serviceException.printStackTrace();
       }
   }
});

Note：

For more samples, please visit GitHub.