Question

我是DynamoDB的新手，我正在尝试插入一个新项目。但是，我得到以下例外：

com.amazonaws.services.dynamodbv2.model.AmazonDynamoDBException: The provided key element does not match the schema (Service: AmazonDynamoDBv2; Status Code: 400; Error Code: ValidationException; Request ID: XXX)

这是我的表格描述：

{
    "Table": {
        "TableArn": "arn:aws:dynamodb:us-east-1:111:table/table-XXX", 
        "AttributeDefinitions": [
            {
                "AttributeName": "timestamp", 
                "AttributeType": "S"
            }, 
            {
                "AttributeName": "title", 
                "AttributeType": "S"
            }
        ], 
        "ProvisionedThroughput": {
            "NumberOfDecreasesToday": 0, 
            "WriteCapacityUnits": 5, 
            "ReadCapacityUnits": 5
        }, 
        "TableSizeBytes": 0, 
        "TableName": "ddb-table-sst67gy", 
        "TableStatus": "ACTIVE", 
        "KeySchema": [
            {
                "KeyType": "HASH", 
                "AttributeName": "title"
            }, 
            {
                "KeyType": "RANGE", 
                "AttributeName": "timestamp"
            }
        ], 
        "ItemCount": 0, 
        "CreationDateTime": 1489090172.658
    }
}

这是我的Java类：

@DynamoDBTable(tableName = "table-XXX")
public class Movie {

    private String title;
    private String timeStamp;

    @DynamoDBHashKey(attributeName = "title")
    @NotNull(message = "Title must not be empty")
    public String getTitle() {
        return title;
    }

    public Movie withTitle(String name) {

        setTitle(name);
        return this;
    }

    @DynamoDBAttribute(attributeName = "timestamp")
    public String getTimeStamp() {
        return timeStamp;
    }

    public Movie withTimeStamp(String address) {
        setTimeStamp(address);
        return this;
    }


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

    public void setTimeStamp(String timeStamp) {
        this.timeStamp = timeStamp;
    }


    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Movie movie = (Movie) o;

        if (title != null ? !title.equals(movie.title) : movie.title != null) return false;
        return timeStamp != null ? timeStamp.equals(movie.timeStamp) : movie.timeStamp == null;
    }

    @Override
    public int hashCode() {
        int result = title != null ? title.hashCode() : 0;
        result = 31 * result + (timeStamp != null ? timeStamp.hashCode() : 0);
        return result;
    }
}

我应该如何正确地将我的Java类映射到DynamoDB？

Answer 1

请使用注释@DynamoDBRangeKey来定义范围或排序键属性。

@DynamoDBRangeKey(attributeName = "timestamp")
public String getTimeStamp() {
    return timeStamp;
}

如何将DynamoDB表映射到Java？

1 个答案: