DynamoDBMapper 批处理操作

以下 Java 代码示例声明了 Book、Forum、Thread 额 Reply 类，并使用 DynamoDBMapper 类将它们映射到 Amazon DynamoDB 表。

该代码说明了以下批处理写入操作：

有关此示例中使用的表的更多信息，请参阅为 DynamoDB 中的代码示例创建表和加载数据。有关测试以下示例的分步说明，请参阅 Java 代码示例。

导入

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
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.DynamoDBRangeKey;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable;

代码

public class DynamoDBMapperBatchWriteExample {

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

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

            DynamoDBMapper mapper = new DynamoDBMapper(client);

            testBatchSave(mapper);
            testBatchDelete(mapper);
            testBatchWrite(mapper);

            System.out.println("Example complete!");

        } catch (Throwable t) {
            System.err.println("Error running the DynamoDBMapperBatchWriteExample: " + t);
            t.printStackTrace();
        }
    }

    private static void testBatchSave(DynamoDBMapper mapper) {

        Book book1 = new Book();
        book1.setId(901);
        book1.setInPublication(true);
        book1.setISBN("902-11-11-1111");
        book1.setPageCount(100);
        book1.setPrice(10);
        book1.setProductCategory("Book");
        book1.setTitle("My book created in batch write");

        Book book2 = new Book();
        book2.setId(902);
        book2.setInPublication(true);
        book2.setISBN("902-11-12-1111");
        book2.setPageCount(200);
        book2.setPrice(20);
        book2.setProductCategory("Book");
        book2.setTitle("My second book created in batch write");

        Book book3 = new Book();
        book3.setId(903);
        book3.setInPublication(false);
        book3.setISBN("902-11-13-1111");
        book3.setPageCount(300);
        book3.setPrice(25);
        book3.setProductCategory("Book");
        book3.setTitle("My third book created in batch write");

        System.out.println("Adding three books to ProductCatalog table.");
        mapper.batchSave(Arrays.asList(book1, book2, book3));
    }

    private static void testBatchDelete(DynamoDBMapper mapper) {

        Book book1 = mapper.load(Book.class, 901);
        Book book2 = mapper.load(Book.class, 902);
        System.out.println("Deleting two books from the ProductCatalog table.");
        mapper.batchDelete(Arrays.asList(book1, book2));
    }

    private static void testBatchWrite(DynamoDBMapper mapper) {

        // Create Forum item to save
        Forum forumItem = new Forum();
        forumItem.setName("Test BatchWrite Forum");
        forumItem.setThreads(0);
        forumItem.setCategory("Amazon Web Services");

        // Create Thread item to save
        Thread threadItem = new Thread();
        threadItem.setForumName("AmazonDynamoDB");
        threadItem.setSubject("My sample question");
        threadItem.setMessage("BatchWrite message");
        List<String> tags = new ArrayList<String>();
        tags.add("batch operations");
        tags.add("write");
        threadItem.setTags(new HashSet<String>(tags));

        // Load ProductCatalog item to delete
        Book book3 = mapper.load(Book.class, 903);

        List<Object> objectsToWrite = Arrays.asList(forumItem, threadItem);
        List<Book> objectsToDelete = Arrays.asList(book3);

        DynamoDBMapperConfig config = DynamoDBMapperConfig.builder()
                .withSaveBehavior(DynamoDBMapperConfig.SaveBehavior.CLOBBER)
                .build();

        mapper.batchWrite(objectsToWrite, objectsToDelete, config);
    }

    @DynamoDBTable(tableName = "ProductCatalog")
    public static class Book {
        private int id;
        private String title;
        private String ISBN;
        private int price;
        private int pageCount;
        private String productCategory;
        private boolean inPublication;

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

        public void setId(int 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 = "Price")
        public int getPrice() {
            return price;
        }

        public void setPrice(int price) {
            this.price = price;
        }

        @DynamoDBAttribute(attributeName = "PageCount")
        public int getPageCount() {
            return pageCount;
        }

        public void setPageCount(int pageCount) {
            this.pageCount = pageCount;
        }

        @DynamoDBAttribute(attributeName = "ProductCategory")
        public String getProductCategory() {
            return productCategory;
        }

        public void setProductCategory(String productCategory) {
            this.productCategory = productCategory;
        }

        @DynamoDBAttribute(attributeName = "InPublication")
        public boolean getInPublication() {
            return inPublication;
        }

        public void setInPublication(boolean inPublication) {
            this.inPublication = inPublication;
        }

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

    }

    @DynamoDBTable(tableName = "Reply")
    public static class Reply {
        private String id;
        private String replyDateTime;
        private String message;
        private String postedBy;

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

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

        // Sort key
        @DynamoDBRangeKey(attributeName = "ReplyDateTime")
        public String getReplyDateTime() {
            return replyDateTime;
        }

        public void setReplyDateTime(String replyDateTime) {
            this.replyDateTime = replyDateTime;
        }

        @DynamoDBAttribute(attributeName = "Message")
        public String getMessage() {
            return message;
        }

        public void setMessage(String message) {
            this.message = message;
        }

        @DynamoDBAttribute(attributeName = "PostedBy")
        public String getPostedBy() {
            return postedBy;
        }

        public void setPostedBy(String postedBy) {
            this.postedBy = postedBy;
        }
    }

    @DynamoDBTable(tableName = "Thread")
    public static class Thread {
        private String forumName;
        private String subject;
        private String message;
        private String lastPostedDateTime;
        private String lastPostedBy;
        private Set<String> tags;
        private int answered;
        private int views;
        private int replies;

        // Partition key
        @DynamoDBHashKey(attributeName = "ForumName")
        public String getForumName() {
            return forumName;
        }

        public void setForumName(String forumName) {
            this.forumName = forumName;
        }

        // Sort key
        @DynamoDBRangeKey(attributeName = "Subject")
        public String getSubject() {
            return subject;
        }

        public void setSubject(String subject) {
            this.subject = subject;
        }

        @DynamoDBAttribute(attributeName = "Message")
        public String getMessage() {
            return message;
        }

        public void setMessage(String message) {
            this.message = message;
        }

        @DynamoDBAttribute(attributeName = "LastPostedDateTime")
        public String getLastPostedDateTime() {
            return lastPostedDateTime;
        }

        public void setLastPostedDateTime(String lastPostedDateTime) {
            this.lastPostedDateTime = lastPostedDateTime;
        }

        @DynamoDBAttribute(attributeName = "LastPostedBy")
        public String getLastPostedBy() {
            return lastPostedBy;
        }

        public void setLastPostedBy(String lastPostedBy) {
            this.lastPostedBy = lastPostedBy;
        }

        @DynamoDBAttribute(attributeName = "Tags")
        public Set<String> getTags() {
            return tags;
        }

        public void setTags(Set<String> tags) {
            this.tags = tags;
        }

        @DynamoDBAttribute(attributeName = "Answered")
        public int getAnswered() {
            return answered;
        }

        public void setAnswered(int answered) {
            this.answered = answered;
        }

        @DynamoDBAttribute(attributeName = "Views")
        public int getViews() {
            return views;
        }

        public void setViews(int views) {
            this.views = views;
        }

        @DynamoDBAttribute(attributeName = "Replies")
        public int getReplies() {
            return replies;
        }

        public void setReplies(int replies) {
            this.replies = replies;
        }

    }

    @DynamoDBTable(tableName = "Forum")
    public static class Forum {
        private String name;
        private String category;
        private int threads;

        // Partition key
        @DynamoDBHashKey(attributeName = "Name")
        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        @DynamoDBAttribute(attributeName = "Category")
        public String getCategory() {
            return category;
        }

        public void setCategory(String category) {
            this.category = category;
        }

        @DynamoDBAttribute(attributeName = "Threads")
        public int getThreads() {
            return threads;
        }

        public void setThreads(int threads) {
            this.threads = threads;
        }
    }
}