Java DynamoDB 增加、删除、修改、查询

2019-05-17 00:03:08来源：博客园阅读 ()

准备jar包

<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk-core</artifactId>
    <version>1.11.534</version>
</dependency>
<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk-dynamodb</artifactId>
    <version>1.11.46</version>
</dependency>

准备对象：

//用户凭证
private static String AWSAccessKeyId = "xxx";
private static String AWSSecretKey = "xxx";
//表名
private static String TABLE_NAME = "xxx";
//用户凭证对象
private static AWSCredentialsProvider awsCredentialsProvider = new AWSCredentialsProvider() {
　　public void refresh() {}
　　public AWSCredentials getCredentials() {return new BasicAWSCredentials(AWSAccessKeyId, AWSSecretKey);}
};
//表的相关对象
private static AmazonDynamoDB amazonDynamoDBClient = null;
private static DynamoDBMapper dbMapper = null;
private static Table table = null;

数据库表映射对象：

@DynamoDBTable(tableName = "xxx")
public class User {
    private String id = null;
    private String name = null;
    private String telephone = null;

    public User(String id, String name, String telephone) {
        super();
        this.id = id;
        this.name = name;
        this.telephone = telephone;
    }
　　//主键
    @DynamoDBHashKey(attributeName = "Id")
    public String getId() {
        return id;
    }

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

    public User() {
    }
　　//配有索引 userName-index
    @DynamoDBAttribute(attributeName = "userName")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
　　//配有索引 telephone-index
    @DynamoDBAttribute(attributeName = "telephone")
    public String getTelephone() {
        return telephone;
    }

    public void setTelephone(String telephone) {
        this.telephone = telephone;
    }
}

初始化对象：

amazonDynamoDBClient =  AmazonDynamoDBClientBuilder.standard().withCredentials(awsCredentialsProvider).withRegion(Regions.AP_NORTHEAST_1).build();
dbMapper = new DynamoDBMapper(amazonDynamoDBClient);
table = new  DynamoDB(amazonDynamoDBClient).getTable(TABLE_NAME);

根据id查询一条：

public static user getItemById(String id) {
        return dbMapper.load(User.class, id);
    }

根据指定索引查询多条：

public static List<User> getItemBykey(String key, String value) {
　　　　//取索引
        Index index = table.getIndex(key + "-index");
        HashMap<String, String> nameMap = new HashMap<String, String>();
        nameMap.put("#key", key);
        HashMap<String, Object> valueMap = new HashMap<String, Object>();
        valueMap.put(":value", value);
　　　　//创建筛选条件，以map的形式传入key和value，条件只能用 = 号，其他未考证
        QuerySpec querySpec = new QuerySpec().withKeyConditionExpression("#key = :value").withNameMap(nameMap)
                .withValueMap(valueMap);
        ItemCollection<QueryOutcome> items = index.query(querySpec);
        Iterator<Item> iterator = items.iterator();
        Item item = null;
        List<User> Users = new ArrayList<User>();
        while (iterator.hasNext()) {
            item = iterator.next();
            dashButtonUsers.add(new DashButtonUser(item.getString("Id"),item.getString("userName"),item.getString("telephone"));
        }
        return Users;
    }

根据指定条件扫描多条：

public static List<User> getItemByTimeRange(Long startTime, Long endTime) {
        Map<String, AttributeValue> expressionAttributeValues = new HashMap<String, AttributeValue>();
        expressionAttributeValues.put(":startTime", new AttributeValue().withN("" + startTime));
        expressionAttributeValues.put(":endTime", new AttributeValue().withN("" + endTime));
　　　　//筛选条件
        ScanRequest scanRequest = new ScanRequest().withTableName(TABLE_NAME)
                .withFilterExpression("startTime >= :startTime and endTime <= :endTime")
                .withExpressionAttributeValues(expressionAttributeValues);
        ScanResult result = amazonDynamoDBClient.scan(scanRequest);
        List<User> users = new ArrayList<User>();
        for (Map<String, AttributeValue> item : result.getItems()) {
                dashButtonUsers.add(new DashButtonUser(/* 略 */));
        }
        return users;
    }

根据id删除：

//删除一条
public static void deleteItemById(String id) {
    dbMapper.delete(new DashButtonUser(id, null, null, null, null, null, null));
    }
//删除多条
public static void deleteBatch(List<User> ids) {
　　//ids[0] -->{"id":"xxx","telephone":null,"name":null}
    dbMapper.batchDelete(ids);
    }

添加、修改：

//添加、修改一条
public static void addOrupdateOneItem(User user) {
        dbMapper.save(user);
    }
//添加、修改多条
public static List<FailedBatch>  addOrUpdateBatch(List<User> users) {
        return dbMapper.batchSave(users);
    }