僅使用hashKey查詢dynamoDB

Question

我想僅使用Hashkey查詢我的dynamoDB。 我的表（名稱= TestTable的）架構如下：

• 字符串自動識別（HashKey）
• 字符串AlexandriaID（RangeKey）
• 字符串DOCTYPE

我dynamoDBQueryExpression是：

---

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); 

---

我在等待一個具有相同autoID的testTable對象列表。由於我是新手，如果我錯了，請糾正我。

當我撥打mapper.query()時沒有任何反應。

在StackOverflow上的問題由Vikdor參考意見 query using hashKey in dynamoDB

進一步編輯：

我確切QueryMethod：

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()); 
    } 
} 

堆棧我的計劃跟蹤：

調用方法保存表中的對象：

***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 

調用方法來查詢自動識別的基礎上，該表：

[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 

在桌子上

掃描操作的輸出：

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 

TestTable的類別：

public class testTable {  
    private String autoID; 
    private String docType; 
    private String alexandriaID;  

    @DynamoDBHashKey(attributeName="autoID") 
    public String getAutoID(){ return autoID;} 
    public void setAutoID(String autoID){ this.autoID = autoID;}  

    @DynamoDBRangeKey(attributeName="alexandriaID") 
    public String getAlexandraiID(){ return alexandriaID;} 
    public void setAlexandriaID(String alexandriaID){ this.alexandriaID = alexandriaID;}  

    @DynamoDBAttribute(attributeName="docType") 
    public String getDocType(){ return docType;}  
    public void setDocType(String docType){ this.docType = docType;}  

} 

Answer 1

正如所討論的，這個問題似乎是在getAlexandraiID聲明中。

請更改方法名稱如下所述： -

來源： -

public String getAlexandraiID(){ return alexandriaID;} 

爲： -

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