如何在java中通过哈希和范围键查询DynamoDB？

在Java中，可以通过哈希和范围键查询DynamoDB。DynamoDB是亚马逊提供的一种NoSQL数据库服务，具有高可扩展性和低延迟的特点。

要在Java中通过哈希和范围键查询DynamoDB，可以使用AWS SDK for Java提供的API。以下是一个示例代码：

import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
import software.amazon.awssdk.services.dynamodb.model.Condition;
import software.amazon.awssdk.services.dynamodb.model.QueryRequest;
import software.amazon.awssdk.services.dynamodb.model.QueryResponse;

import java.util.HashMap;
import java.util.Map;

public class DynamoDBQueryExample {
    public static void main(String[] args) {
        // 创建DynamoDB客户端
        DynamoDbClient dynamoDbClient = DynamoDbClient.create();

        // 构建查询请求
        QueryRequest queryRequest = QueryRequest.builder()
                .tableName("your_table_name")
                .keyConditionExpression("#hashKey = :hashValue and #rangeKey between :rangeStart and :rangeEnd")
                .expressionAttributeNames(getExpressionAttributeNames())
                .expressionAttributeValues(getExpressionAttributeValues())
                .build();

        // 发起查询请求
        QueryResponse queryResponse = dynamoDbClient.query(queryRequest);

        // 处理查询结果
        queryResponse.items().forEach(item -> {
            // 处理每个返回的项
            // ...
        });
    }

    private static Map<String, String> getExpressionAttributeNames() {
        Map<String, String> expressionAttributeNames = new HashMap<>();
        expressionAttributeNames.put("#hashKey", "your_hash_key_attribute_name");
        expressionAttributeNames.put("#rangeKey", "your_range_key_attribute_name");
        return expressionAttributeNames;
    }

    private static Map<String, AttributeValue> getExpressionAttributeValues() {
        Map<String, AttributeValue> expressionAttributeValues = new HashMap<>();
        expressionAttributeValues.put(":hashValue", AttributeValue.builder().s("your_hash_key_value").build());
        expressionAttributeValues.put(":rangeStart", AttributeValue.builder().n("your_range_start_value").build());
        expressionAttributeValues.put(":rangeEnd", AttributeValue.builder().n("your_range_end_value").build());
        return expressionAttributeValues;
    }
}

上述代码中，需要替换以下部分：