Java 实现 DynamoDB 查询的 IN 表达式

最新推荐文章于 2024-03-01 16:58:55 发布

原创最新推荐文章于 2024-03-01 16:58:55 发布 · 472 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#java #aws

AWS 专栏收录该内容

6 篇文章

订阅专栏

该代码示例展示了如何使用Java和AWSSDKforDynamoDB执行一个查询，通过指定的属性名和一组值来过滤DynamoDB表中的记录。程序首先定义了区域、DynamoDbClient实例，然后设置表名、属性名和搜索值，构建过滤表达式，并执行扫描请求来获取匹配的项。

示例如下

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.*;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class DynamoDBQueryExample {

    public static void main(String[] args) {
        Region region = Region.US_EAST_1;
        DynamoDbClient client = DynamoDbClient.builder().region(region).build();

        String tableName = "YourTableName";
        String attributeName = "YourAttributeName";
        List<String> searchValues = List.of("Value1", "Value2", "Value3");

        Map<String, AttributeValue> expressionAttributeValues = new HashMap<>();
        for (int i = 0; i < searchValues.size(); i++) {
            expressionAttributeValues.put(":value" + i, AttributeValue.builder().s(searchValues.get(i)).build());
        }

        String filterExpression = "#attrName IN (" + String.join(",", expressionAttributeValues.keySet()) + ")";

        ScanResponse response = client.scan(ScanRequest.builder()
                .tableName(tableName)
                .filterExpression(filterExpression)
                .expressionAttributeNames(Map.of("#attrName", attributeName))
                .expressionAttributeValues(expressionAttributeValues)
                .build());

        System.out.println("Matching items:");
        for (Map<String, AttributeValue> item : response.items()) {
            System.out.println(item);
        }
    }
}