write to Amazon DynamoDB

Description

Demo Code


import java.io.IOException;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.services.dynamodb.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodb.model.AttributeValue;
import com.amazonaws.services.dynamodb.model.CreateTableRequest;
import com.amazonaws.services.dynamodb.model.DescribeTableRequest;
import com.amazonaws.services.dynamodb.model.KeySchema;
import com.amazonaws.services.dynamodb.model.KeySchemaElement;
import com.amazonaws.services.dynamodb.model.ProvisionedThroughput;
import com.amazonaws.services.dynamodb.model.PutItemRequest;
import com.amazonaws.services.dynamodb.model.PutItemResult;
import com.amazonaws.services.dynamodb.model.TableDescription;
import com.amazonaws.services.dynamodb.model.TableStatus;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

public class MongotoDynamo {

    static AmazonDynamoDBClient dynamoDB;

    static String tableName = "my-favorite-table";
    static BasicDBObject[] objects;

    public static void main(String[] args) throws IOException {

        init();//from  w w  w.jav  a2 s .c  om

        readfromMongo();

        writetoDynamo();
    }
    private static void writetoDynamo() {
        CreateTableRequest createTableRequest = new CreateTableRequest()
                .withTableName(tableName)
                .withKeySchema(
                        new KeySchema(new KeySchemaElement()
                                .withAttributeName("name")
                                .withAttributeType("S")))
                .withProvisionedThroughput(
                        new ProvisionedThroughput().withReadCapacityUnits(
                                10L).withWriteCapacityUnits(5L));
        TableDescription createdTableDescription = dynamoDB.createTable(
                createTableRequest).getTableDescription();
        System.out.println("Created Table: " + createdTableDescription);

        waitForTableToBecomeAvailable(tableName);

        DescribeTableRequest describeTableRequest = new DescribeTableRequest()
                .withTableName(tableName);
        TableDescription tableDescription = dynamoDB.describeTable(
                describeTableRequest).getTable();
        System.out.println("Table Description: " + tableDescription);

        for (int i = 0; i < objects.length; i++) {
            Map<String, AttributeValue> item = newItem(objects[i]);
            PutItemRequest putItemRequest = new PutItemRequest(tableName,
                    item);
            PutItemResult putItemResult = dynamoDB.putItem(putItemRequest);
            System.out.println("Result: " + putItemResult);
        }

    }

    private static Map<String, AttributeValue> newItem(BasicDBObject object) {

        Map<String, AttributeValue> item = new HashMap<String, AttributeValue>();
        Object[] keynames = object.keySet().toArray();
        for (int i = 0; i < keynames.length; i++) {
            item.put(keynames[i].toString(),
                    new AttributeValue(object.get(keynames[i].toString())
                            .toString()));
        }

        return item;
    }

    private static void waitForTableToBecomeAvailable(String tableName) {

        System.out.println("Waiting for " + tableName
                + " to become ACTIVE...");

        long startTime = System.currentTimeMillis();
        long endTime = startTime + (10 * 60 * 1000);
        while (System.currentTimeMillis() < endTime) {
            try {
                Thread.sleep(1000 * 20);
            } catch (Exception e) {
            }
            try {
                DescribeTableRequest request = new DescribeTableRequest()
                        .withTableName(tableName);
                TableDescription tableDescription = dynamoDB.describeTable(
                        request).getTable();
                String tableStatus = tableDescription.getTableStatus();
                System.out.println("  - current state: " + tableStatus);
                if (tableStatus.equals(TableStatus.ACTIVE.toString()))
                    return;
            } catch (AmazonServiceException ase) {
                if (ase.getErrorCode().equalsIgnoreCase(
                        "ResourceNotFoundException") == false)
                    throw ase;
            }
        }

        throw new RuntimeException("Table " + tableName
                + " never went active");
    }

    private static void readfromMongo() throws UnknownHostException,
            MongoException {

        Mongo mongo;
        mongo = new Mongo("10.3.4.84", 27017);
        mongo.getDB("db").authenticate("cssc", new char[] { '1' });
        DB db = mongo.getDB("db");
        Object[] collectionnames = db.getCollectionNames().toArray();
        for (int i = 0; i < 1; i++) {
            System.out.println("Name of Collection: " + collectionnames[i]);
            tableName = collectionnames[i].toString();
            DBCollection collection = db.getCollection(collectionnames[i]
                    .toString());
            DBCursor cursor = collection.find();

            objects = new BasicDBObject[cursor.size()];
            for (int j = 0; cursor.hasNext(); j++) {
                BasicDBObject object = (BasicDBObject) cursor.next();
                objects[j] = object;
                Object[] keynames = object.keySet().toArray();
                for (int k = 0; k < keynames.length; k++) {
                    System.out.println("Key: " + keynames[k]
                            + " Attribute: "
                            + object.getString(keynames[k].toString()));
                }
            }
        }
    }

    private static void init() throws IOException {

        AWSCredentials credentials = new PropertiesCredentials(
                MongotoDynamo.class
                        .getResourceAsStream("AwsCredentials.properties"));

        dynamoDB = new AmazonDynamoDBClient(credentials);
    }

}
write to Amazon DynamoDB - Java AWS

Description

Demo Code

Related Tutorials
