Java tutorial
/* * Copyright 2012-2014 Boundary, 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. */ package com.boundary.aws.dynamodb; 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.QueryRequest; import com.amazonaws.services.dynamodbv2.model.QueryResult; 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.Tables; /** * Example of continuously querying DynamoDB */ public class QueryDynamoDB { 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/davidg/.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." + e); } dynamoDB = new AmazonDynamoDBClient(credentials); Region usWest1 = Region.getRegion(Regions.US_WEST_1); dynamoDB.setRegion(usWest1); } public static void main(String[] args) throws Exception { init(); try { String tableName = "my-favorite-movies-table"; // Create table if it does not exist yet if (Tables.doesTableExist(dynamoDB, tableName)) { System.out.println("Table " + tableName + " is already ACTIVE"); } else { System.out.println("Table to query " + tableName + "does not exist"); } while (true) { // Scan items for movies with a year attribute greater than 1985 HashMap<String, Condition> scanFilter = new HashMap<String, Condition>(); Condition scanCondition = new Condition().withComparisonOperator(ComparisonOperator.GT.toString()) .withAttributeValueList(new AttributeValue().withN("1985")); scanFilter.put("year", scanCondition); ScanRequest scanRequest = new ScanRequest(tableName).withScanFilter(scanFilter); ScanResult scanResult = dynamoDB.scan(scanRequest); System.out.println("Result: " + scanResult); Condition hashKeyCondition = new Condition().withComparisonOperator(ComparisonOperator.EQ) .withAttributeValueList(new AttributeValue().withS("Matrix")); Map<String, Condition> keyConditions = new HashMap<String, Condition>(); keyConditions.put("name", hashKeyCondition); QueryRequest queryRequest = new QueryRequest().withTableName(tableName) .withKeyConditions(keyConditions); QueryResult queryResult = dynamoDB.query(queryRequest); System.out.println("Result: " + queryResult); Thread.sleep(5000); } } 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()); } } }