Java tutorial
/* * Copyright 2012-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. */ import java.util.HashMap; import java.util.Map; import com.amazonaws.AmazonClientException; import com.amazonaws.AmazonServiceException; import com.amazonaws.auth.AWSCredentials; import com.amazonaws.auth.profile.ProfileCredentialsProvider; import com.amazonaws.regions.Region; import com.amazonaws.regions.Regions; import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient; import com.amazonaws.services.dynamodbv2.model.AttributeDefinition; import com.amazonaws.services.dynamodbv2.model.AttributeValue; import com.amazonaws.services.dynamodbv2.model.ComparisonOperator; import com.amazonaws.services.dynamodbv2.model.Condition; import com.amazonaws.services.dynamodbv2.model.CreateTableRequest; import com.amazonaws.services.dynamodbv2.model.DescribeTableRequest; import com.amazonaws.services.dynamodbv2.model.KeySchemaElement; import com.amazonaws.services.dynamodbv2.model.KeyType; import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput; import com.amazonaws.services.dynamodbv2.model.PutItemRequest; import com.amazonaws.services.dynamodbv2.model.PutItemResult; import com.amazonaws.services.dynamodbv2.model.ReturnValue; import com.amazonaws.services.dynamodbv2.model.ScalarAttributeType; import com.amazonaws.services.dynamodbv2.model.ScanRequest; import com.amazonaws.services.dynamodbv2.model.ScanResult; import com.amazonaws.services.dynamodbv2.model.TableDescription; import com.amazonaws.services.dynamodbv2.util.TableUtils; /** * This sample demonstrates how to perform a few simple operations with the * Amazon DynamoDB service. * * Run this file to see put throttling. * * At beginning, the put requests are processed although the volume beyond write capacity. * After a while, the put requests are slower. But not lots of put requests are throttled. * It might because that the SDK exponential backoff of the automatic retry. */ public class AmazonDynamoDBSample_PutThrottled { /* * Before running the code: Fill in your AWS access credentials in the * provided credentials file template, and be sure to move the file to the * default location (/Users/haifengw/.aws/credentials) where the sample code * will load the credentials from. * https://console.aws.amazon.com/iam/home?#security_credential * * WARNING: To avoid accidental leakage of your credentials, DO NOT keep the * credentials file in your source directory. */ static AmazonDynamoDBClient dynamoDB; /** * The only information needed to create a client are security credentials * consisting of the AWS Access Key ID and Secret Access Key. All other * configuration, such as the service endpoints, are performed * automatically. Client parameters, such as proxies, can be specified in an * optional ClientConfiguration object when constructing a client. * * @see com.amazonaws.auth.BasicAWSCredentials * @see com.amazonaws.auth.ProfilesConfigFile * @see com.amazonaws.ClientConfiguration */ private static void init() throws Exception { /* * The ProfileCredentialsProvider will return your [default] credential * profile by reading from the credentials file located at * (/Users/haifengw/.aws/credentials). */ AWSCredentials credentials = null; try { credentials = new ProfileCredentialsProvider("default").getCredentials(); } catch (Exception e) { throw new AmazonClientException("Cannot load the credentials from the credential profiles file. " + "Please make sure that your credentials file is at the correct " + "location (/Users/haifengw/.aws/credentials), and is in valid format.", e); } dynamoDB = new AmazonDynamoDBClient(credentials); Region usWest2 = Region.getRegion(Regions.US_WEST_2); dynamoDB.setRegion(usWest2); } public static void main(String[] args) throws Exception { init(); try { String tableName = "my-favorite-movies-table"; // Create a table with a primary hash key named 'name', which holds // a string CreateTableRequest createTableRequest = new CreateTableRequest().withTableName(tableName) .withKeySchema(new KeySchemaElement().withAttributeName("name").withKeyType(KeyType.HASH)) .withAttributeDefinitions(new AttributeDefinition().withAttributeName("name") .withAttributeType(ScalarAttributeType.S)) .withProvisionedThroughput( new ProvisionedThroughput().withReadCapacityUnits(1L).withWriteCapacityUnits(1L)); // Create table if it does not exist yet TableUtils.createTableIfNotExists(dynamoDB, createTableRequest); // wait for the table to move into ACTIVE state TableUtils.waitUntilActive(dynamoDB, tableName); // Describe our new table DescribeTableRequest describeTableRequest = new DescribeTableRequest().withTableName(tableName); TableDescription tableDescription = dynamoDB.describeTable(describeTableRequest).getTable(); System.out.println("Table Description: " + tableDescription); // Add an item Map<String, AttributeValue> item = newItem("Bill & Ted's Excellent Adventure", 1989, "****", "James", "Sara"); PutItemRequest putItemRequest = new PutItemRequest(tableName, item); PutItemResult putItemResult = dynamoDB.putItem(putItemRequest); System.out.println("Result: " + putItemResult); // Add another item item = newItem("Airplane", 1980, "*****", "James", "Billy Bob"); putItemRequest = new PutItemRequest(tableName, item); putItemResult = dynamoDB.putItem(putItemRequest); System.out.println("Result: " + putItemResult); Thread[] thrds = new Thread[16]; for (int i = 0; i < thrds.length; i++) { thrds[i] = newItemCreationThread(tableName, i); thrds[i].start(); } for (Thread thrd : thrds) { thrd.join(); } // Scan items for movies with a year attribute greater than 1985 HashMap<String, Condition> scanFilter = new HashMap<String, Condition>(); Condition condition = new Condition().withComparisonOperator(ComparisonOperator.GT.toString()) .withAttributeValueList(new AttributeValue().withN("1985")); scanFilter.put("year", condition); ScanRequest scanRequest = new ScanRequest(tableName).withScanFilter(scanFilter); ScanResult scanResult = dynamoDB.scan(scanRequest); System.out.println("Result: " + scanResult); } catch (AmazonServiceException ase) { System.out.println("Caught an AmazonServiceException, which means your request made it " + "to AWS, but was rejected with an error response for some reason."); System.out.println("Error Message: " + ase.getMessage()); System.out.println("HTTP Status Code: " + ase.getStatusCode()); System.out.println("AWS Error Code: " + ase.getErrorCode()); System.out.println("Error Type: " + ase.getErrorType()); System.out.println("Request ID: " + ase.getRequestId()); } catch (AmazonClientException ace) { System.out.println("Caught an AmazonClientException, which means the client encountered " + "a serious internal problem while trying to communicate with AWS, " + "such as not being able to access the network."); System.out.println("Error Message: " + ace.getMessage()); } } private static Thread newItemCreationThread(String tableName, final int thrdNo) { final int ITEM_COUNTS = 1000 * 1000; return new Thread(() -> { for (int c = 0; c < ITEM_COUNTS; c++) { Map<String, AttributeValue> item = new HashMap<>(); String pk = String.format("pk name: thrd %d creates %dth item", thrdNo, c); item.put("name", new AttributeValue(pk)); PutItemRequest req = new PutItemRequest(tableName, item); req.setReturnValues(ReturnValue.ALL_OLD); PutItemResult res = null; long t = System.currentTimeMillis(); try { res = dynamoDB.putItem(req); } catch (Exception exob) { exob.printStackTrace(); } assert 0 == res.getAttributes().size(); System.out.printf("%s. takes %d ms\n", pk, System.currentTimeMillis() - t); } }); } private static Map<String, AttributeValue> newItem(String name, int year, String rating, String... fans) { Map<String, AttributeValue> item = new HashMap<String, AttributeValue>(); item.put("name", new AttributeValue(name)); item.put("year", new AttributeValue().withN(Integer.toString(year))); item.put("rating", new AttributeValue(rating)); item.put("fans", new AttributeValue().withSS(fans)); return item; } }