Operasi CRUD DynamoDBMapper

Contoh kode Java berikut menyatakan kelas CatalogItem yang memiliki properti Id, Title, ISBN, dan Authors. Contoh ini menggunakan anotasi untuk memetakan properti ini ke tabel ProductCatalog di DynamoDB. Contoh kemudian menggunakan DynamoDBMapper untuk menyimpan objek buku, mengambilnya, memperbaruinya, lalu menghapus item buku.

Impor

import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBHashKey;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable;

Kode

public class DynamoDBMapperCRUDExample {

    static AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().build();

    public static void main(String[] args) throws IOException {
        testCRUDOperations();
        System.out.println("Example complete!");
    }

    @DynamoDBTable(tableName = "ProductCatalog")
    public static class CatalogItem {
        private Integer id;
        private String title;
        private String ISBN;
        private Set<String> bookAuthors;

        // Partition key
        @DynamoDBHashKey(attributeName = "Id")
        public Integer getId() {
            return id;
        }

        public void setId(Integer id) {
            this.id = id;
        }

        @DynamoDBAttribute(attributeName = "Title")
        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        @DynamoDBAttribute(attributeName = "ISBN")
        public String getISBN() {
            return ISBN;
        }

        public void setISBN(String ISBN) {
            this.ISBN = ISBN;
        }

        @DynamoDBAttribute(attributeName = "Authors")
        public Set<String> getBookAuthors() {
            return bookAuthors;
        }

        public void setBookAuthors(Set<String> bookAuthors) {
            this.bookAuthors = bookAuthors;
        }

        @Override
        public String toString() {
            return "Book [ISBN=" + ISBN + ", bookAuthors=" + bookAuthors + ", id=" + id + ", title=" + title + "]";
        }
    }

    private static void testCRUDOperations() {

        CatalogItem item = new CatalogItem();
        item.setId(601);
        item.setTitle("Book 601");
        item.setISBN("611-1111111111");
        item.setBookAuthors(new HashSet<String>(Arrays.asList("Author1", "Author2")));

        // Save the item (book).
        DynamoDBMapper mapper = new DynamoDBMapper(client);
        mapper.save(item);

        // Retrieve the item.
        CatalogItem itemRetrieved = mapper.load(CatalogItem.class, 601);
        System.out.println("Item retrieved:");
        System.out.println(itemRetrieved);

        // Update the item.
        itemRetrieved.setISBN("622-2222222222");
        itemRetrieved.setBookAuthors(new HashSet<String>(Arrays.asList("Author1", "Author3")));
        mapper.save(itemRetrieved);
        System.out.println("Item updated:");
        System.out.println(itemRetrieved);

        // Retrieve the updated item.
        DynamoDBMapperConfig config = DynamoDBMapperConfig.builder()
                .withConsistentReads(DynamoDBMapperConfig.ConsistentReads.CONSISTENT)
                .build();
        CatalogItem updatedItem = mapper.load(CatalogItem.class, 601, config);
        System.out.println("Retrieved the previously updated item:");
        System.out.println(updatedItem);

        // Delete the item.
        mapper.delete(updatedItem);

        // Try to retrieve deleted item.
        CatalogItem deletedItem = mapper.load(CatalogItem.class, updatedItem.getId(), config);
        if (deletedItem == null) {
            System.out.println("Done - Sample item is deleted.");
        }
    }
}