Question

我是Dynamo db的新手。我必须实施分页。我必须在我的html页面中显示十条记录。我对dynamo db完全不熟悉。任何人都可以在dynamo db中共享任何分页示例查询。我学过亚马逊发电机数据库教程，但我没有任何想法。我可以使用高级和低级api实现分页吗？任何人都可以建议从哪里开始??

Answer 1

正如yegor256建议的那样，您可以使用查询（QueryRequest）或扫描（ScanRequest）来代替 setExclusiveStartKey 。这是一个如何操作的代码片段

HashMap<String, Condition> scanFilter = new HashMap<String, Condition>();
Condition condition = new Condition()
            .withComparisonOperator(ComparisonOperator.LT.toString())
            .withAttributeValueList(new AttributeValue().withN("100"));
scanFilter.put("column1", condition);
Boolean lastEval = true;
int count = 0;
ScanRequest scanRequest = new ScanRequest(tableName).withScanFilter(scanFilter);
while(lastEval) {
    ScanResult scanResult = dynamoDB.scan(scanRequest);
    count += scanResult.getCount();
    System.out.println("Page Size: " + scanResult.getCount());
    System.out.println("Total count = " + count);
    if (scanResult.getLastEvaluatedKey() != null)
        lastEval = scanResult.getLastEvaluatedKey().isEmpty() == false;
    else
        lastEval = false;
    if (lastEval) {
        scanRequest.setExclusiveStartKey(scanResult.getLastEvaluatedKey());
    }
}

Answer 2

您应该query(QueryRequest)或scan(ScanRequest)使用addExclusiveStartKeyEntry()

另外，请检查此库：jcabi-dynamo

java中的DynamoDb分页查询

2 个答案: