使用DynamoDBmapper查询GSI的当前方法，按排序键排序，并返回n个结果？

Question

当前使用DynamoDBmapper和DynamoDBQueryExpression查询全局辅助索引、按排序索引排序并返回前n个结果的方法是什么？

                Map<String, AttributeValue> eav = new HashMap<String, AttributeValue>();
                eav.put(":val1", new AttributeValue().withS(Leaderboard));

                DynamoDBScanExpression scanExpression = new DynamoDBScanExpression()
                        .withFilterExpression("Leaderboard = :val1") // and Ranking <= :val2")
                        .withExpressionAttributeValues(eav);

@DynamoDBTable(tableName = "Users")

public class DynamoLeaderboard implements Serializable {

    private String leaderboard;
    private String userName;
    private int ranking;

    public DynamoLeaderboard() {}

    @DynamoDBIndexHashKey(globalSecondaryIndexName = "Leaderboard-Ranking-index", attributeName = "Leaderboard")
    public String getLeaderboard() {
        return leaderboard;
    }
    public void setLeaderboard(final String leaderboard) {
        this.leaderboard = leaderboard;
    }

    @DynamoDBIndexRangeKey(globalSecondaryIndexName = "Leaderboard-Ranking-index", attributeName = "Ranking")
    public int getRanking() {
        return ranking;
    }
    public void setRanking(int ranking) {
        this.ranking = ranking;
    }

    @DynamoDBAttribute(attributeName = "UserName")
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
}

final DynamoLeaderboard tmpLeaderboard = new DynamoLeaderboard();
tmpLeaderboard.setLeaderboard("0");

Map<String, AttributeValue> eav = new HashMap<String, AttributeValue>();
eav.put(":val1", new AttributeValue().withS("0"));

DynamoDBQueryExpression<DynamoLeaderboard> queryExpression = new DynamoDBQueryExpression<DynamoLeaderboard>();
queryExpression.withIndexName("Leaderboard-index");
queryExpression.setHashKeyValues(tmpLeaderboard);
queryExpression.withConsistentRead(false);

scanResult = mapper.query(DynamoLeaderboard.class, queryExpression);

关于在GSI上执行查询的当前正确方式的建议？

非常感谢！

Answer 1

您需要将主表的关键属性添加到您的模型中。由于@DynamOdbTable注释类没有@DynamOdbHashKey属性，DynamoDBMapper停滞不前。

或者，可以尝试将@dynamodbtable更改为@dynamodbdocument，但我不太确定这是否可行。