records = s3EventNotification.getRecords();
S3EventNotificationRecord record = records.stream().findFirst();
// Use getters on the record to access individual attributes.
String awsRegion = record.getAwsRegion();
String eventName = record.getEventName();
String eventSource = record.getEventSource();
}
}
```
In this example, the `fromJson` method converts the JSON string into an `S3EventNotification` object. Missing fields in the JSON string will result in `null` values in the corresponding Java object fields and any extra fields in the JSON will be ignored.
Other APIs for an event notification record can be found in API reference for `[S3EventNotificationRecord](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/eventnotifications/s3/model/S3EventNotificationRecord.html)`.
#### Convert an `S3EventNotification` instance to a JSON string
Use the `toJson` (or `toJsonPretty`) method to convert an `S3EventNotification` object into a JSON string as shown in the following example.
```
import software.amazon.awssdk.eventnotifications.s3.model.S3EventNotification
public class S3EventNotificationExample {
...
void toJsonString(S3EventNotification event) {
String json = event.toJson();
String jsonPretty = event.toJsonPretty();
System.out.println("JSON: " + json);
System.out.println("Pretty JSON: " + jsonPretty);
}
}
```
Fields for `GlacierEventData`, `ReplicationEventData`, `IntelligentTieringEventData`, and `LifecycleEventData` are excluded from the JSON if they are `null`. Other `null` fields will be serialized as `null`.
The following shows example output of the `toJsonPretty` method for an S3 object tagging event.
```
{
"Records" : [ {
"eventVersion" : "2.3",
"eventSource" : "aws:s3",
"awsRegion" : "us-east-1",
"eventTime" : "2024-07-19T20:09:18.551Z",
"eventName" : "ObjectTagging:Put",
"userIdentity" : {
"principalId" : "AWS:XXXXXXXXXXX"
},
"requestParameters" : {
"sourceIPAddress" : "XXX.XX.XX.XX"
},
"responseElements" : {
"x-amz-request-id" : "XXXXXXXXXXXX",
"x-amz-id-2" : "XXXXXXXXXXXXX"
},
"s3" : {
"s3SchemaVersion" : "1.0",
"configurationId" : "XXXXXXXXXXXXX",
"bucket" : {
"name" : "amzn-s3-demo-bucket",
"ownerIdentity" : {
"principalId" : "XXXXXXXXXXX"
},
"arn" : "arn:aws:s3:::XXXXXXXXXX"
},
"object" : {
"key" : "akey",
"size" : null,
"eTag" : "XXXXXXXXXX",
"versionId" : null,
"sequencer" : null
}
}
} ]
}
```
A [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/blob/75c3daadf750406156fc87fa30ee499a206b4a36/javav2/example_code/s3/src/main/java/com/example/s3/ProcessS3EventNotification.java#L117) is available in GitHub that shows how to use the API to work with notifications received by an Amazon SQS queue.
## Process S3 Events in Lambda with Java Libraries: AWS SDK for Java 2.x and `aws-lambda-java-events`
Instead of using the SDK for Java 2.x to process Amazon S3 event notifications in a Lambda function, you can use the `[aws-lambda-java-events](https://github.com/aws/aws-lambda-java-libs/tree/main/aws-lambda-java-events)` library at version 3.x.x. AWS maintains the `aws-lambda-java-events` library independently, and it has its own dependency requirements. The `aws-lambda-java-events` library works only with S3 events in Lambda functions, whereas the SDK for Java 2.x works with S3 events in Lambda functions, Amazon SNS, and Amazon SQS.
Both approaches model the JSON event notification payload in an object-oriented way with similar APIs. The following table shows the notable differences between using the two approaches.
****
| | AWS SDK for Java | aws-lambda-java-events library |
| --- | --- | --- |
| Package naming | `software.amazon.awssdk.eventnotifications.s3.model.S3EventNotification` | com.amazonaws.services.lambda.runtime.events.models.s3.S3EventNotification |
| RequestHandler parameter | Write your Lambda function's `RequestHandler` implementation to receive a JSON String: import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import software.amazon.awssdk.eventnotifications.s3.model.S3EventNotification;
public class Handler implements RequestHandler {
@Override
public String handleRequest(String jsonS3Event, Context context) {
S3EventNotification s3Event = S3EventNotification
.fromJson(jsonS3Event);
// Work with the s3Event object.
...
}
}
| Write your Lambda function's RequestHandler implementation to receive an S3Event object:import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.S3Event;
public class Handler implements RequestHandler {
@Override
public String handleRequest(S3Event s3event, Context context) {
// Work with the s3Event object.
...
}
}
|
| Maven dependencies |
software.amazon.awssdk
bom
2.X.X
pom
import
software.amazon.awssdk
s3-event-notifications
|
software.amazon.awssdk
bom
2.X.X
pom
import
com.amazonaws
aws-lambda-java-core
1.2.3
com.amazonaws
aws-lambda-java-events
3.15.0
|