Question

我想仅使用Hashkey查询我的dynamoDB。我的表（name = testTable）模式如下：

字符串autoID（HashKey）
String AlexandriaID（RangeKey）
String docType

我的dynamoDBQueryExpression是：

None

我期待一个具有相同autoID的testTable对象列表。因为我是新手，如果我错了，请纠正我。

当我拨打String hashKey = "dummyHashKey"; testTable hashKeyValues = new testTable(); hashKeyValues.setAutoID(hashKey); DynamoDBQueryExpression<testTable> queryExpression = new DynamoDBQueryExpression<testTable>(); queryExpression.withHashKeyValues(hashKeyValues); //Assuming I have a dynamoDBMapper object mapper List<testTable> docList = mapper.query(testTable.class, queryExpression);电话时没有任何反应。

Vikdor在StackOverflow问题上引用评论 query using hashKey in dynamoDB

进一步修改：

我的确切QueryMethod：

mapper.query()

我的程序的堆栈跟踪：

调用方法来保存表中的对象：

public void queryFromRFIDocumentDetails(String hashKey){
    System.out.println((new Throwable()).getStackTrace()[0].toString() + "***Enter***");

    testTable hashKeyValues = new testTable();
    hashKeyValues.setAutoID(hashKey);

    System.out.println("AutoID for hashKeyValues " + hashKeyValues.getAutoID());
    System.out.println("DocTYpe for hashKeyValues " + hashKeyValues.getDocType());
    System.out.println("AlexandriaID for hashKeyValues " + hashKeyValues.getAlexandraiID());

    DynamoDBQueryExpression<testTable> queryExpression = new DynamoDBQueryExpression<testTable>();
    queryExpression.withHashKeyValues(hashKeyValues);
    queryExpression.withConsistentRead(false);

    System.out.println("calling mapper.query");  //nothing happens after this

    List<testTable> docList = new ArrayList<testTable>();
    docList = mapper.query(testTable.class, queryExpression);

    for(int i=0; i<docList.size(); i++){
        System.out.println("***iterating at retrieved index " + i);
        System.out.println("AutoID for retrieved document " + docList.get(i).getAutoID());
        System.out.println("DocTYpe for retrieved document " + docList.get(i).getDocType());
        System.out.println("AlexandriaID for retrieved document " + docList.get(i).getAlexandraiID());
    }
}

调用方法以autoID：

为基础查询表

***iterating at index 0
[java] AutoID for document to be saved abc
[java] DocTYpe for document to be saved foo
[java] AlexandriaID for document to be saved id1
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:201)***Enter***
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:203)***Exit***
[java] ***iterating at index 1
[java] AutoID for document to be saved abc
[java] DocTYpe for document to be saved foo
[java] AlexandriaID for document to be saved id2
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:201)***Enter***
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:203)***Exit***
[java] ***iterating at index 2
[java] AutoID for document to be saved abc
[java] DocTYpe for document to be saved foo
[java] AlexandriaID for document to be saved id3
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:201)***Enter***
[java] com.amazon.sduservice.db.dynamoDB.saveInRFIDocumentDetails(dynamoDB.java:203)***Exit***
[java] hashKey is abc

桌面扫描操作输出：

[java] com.amazon.sduservice.db.dynamoDB.queryFromRFIDocumentDetails(dynamoDB.java:207)***Enter***
[java] AutoID for hashKeyValues abc
[java] DocTYpe for hashKeyValues null
[java] AlexandriaID for hashKeyValues null
[java] calling mapper.query

testTable类：

Scanning Table RFIDocumentDetails
 [java] {docType={S: foo,}, autoID={S: abc,}, alexandriaID={S: id1,}}
 [java] {docType={S: foo,}, autoID={S: abc,}, alexandriaID={S: id2,}}
 [java] {docType={S: foo,}, autoID={S: abc,}, alexandriaID={S: id3,}}
 [java] {docType={S: pdf,}, autoID={S: HashKey,}, alexandriaID={S: alexandriaID1,}}
 [java] {docType={S: pdf,}, autoID={S: HashKey,}, alexandriaID={S: alexandriaID2,}}
 [java] {docType={S: foo,}, autoID={S: asdf,}, alexandriaID={S: id1,}}
 [java] {docType={S: foo,}, autoID={S: asdf,}, alexandriaID={S: id2,}}
 [java] {docType={S: foo,}, autoID={S: foo,}, alexandriaID={S: id1,}}
 [java] {docType={S: foo,}, autoID={S: foo,}, alexandriaID={S: id2,}}
 [java] Scanning Table Finishes

Answer 1

如上所述，问题似乎出现在getAlexandraiID声明中。

请更改方法名称，如下所述： -

发件人： -

public String getAlexandraiID(){ return alexandriaID;}

要： -

@DynamoDBRangeKey(attributeName = "alexandriaID") public String getAlexandriaID() { return alexandriaID; }

仅使用hashKey查询dynamoDB

1 个答案: