java - 如何从 Android 更新 DynamoDB 中的项目？

Question

标题描述了三天来围绕我的痛苦的问题。如何从 Android 应用程序更新 DynamoDB 中存储的项目？

下面我留下了我已经检查和实现但结果不成功的链接列表:

1 - https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/examples-dynamodb-items.html结果:它严格适用于java ee，不适用于android

2 - https://docs.aws.amazon.com/aws-mobile/latest/developerguide/add-aws-mobile-nosql-database.html#add-aws-mobile-nosql-database-crud-update结果:即使“unique-user-id”参数显然是唯一的，也会创建一个新项目

3 - https://docs.aws.amazon.com/aws-mobile/latest/developerguide/how-to-nosql-integrate-an-existing-table.html结果:同上，创建一个新的

4 - https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBMapper.CRUDExample1.html结果:检索但创建一个新的项目

Answer 1

我做错了事情:- 不包括要发送更新的对象中的排序(也称为范围)键。

对于其余的:首先，获取您的 DynamoDBClient，我强烈建议实现单例模式来调用它，在本例中我使用了 configuration.json:

AWSMobileClient.getInstance().initialize(NewPatientActivity.this).execute();
    AWSCredentialsProvider credentialsProvider = AWSMobileClient.getInstance().getCredentialsProvider();
    AWSConfiguration configuration = AWSMobileClient.getInstance().getConfiguration();
    // Add code to instantiate a AmazonDynamoDBClient
    AmazonDynamoDBClient dynamoDBClient = new AmazonDynamoDBClient(credentialsProvider);

然后设置一个 UpdateItemRequest，如下所示:

//SET THE KEYS VALUES
HashMap<String, AttributeValue> key = new HashMap<String, AttributeValue>();
            key.put("your-partition-key", new AttributeValue().withS(value));
            key.put("your-sort-key-if-exists", new AttributeValue().withS(value));
//SET VALUES TO REPLACE OLD ONES
 Map<String, AttributeValue> expressionAttributeValues = new HashMap<String, AttributeValue>();
            expressionAttributeValues.put(":val1",new AttributeValue().withN(value1));
            expressionAttributeValues.put(":val2", new AttributeValue().withS(value2));
/*
IF YOU WANT TO READ THE JUST-UPDATED ITEM, HAVE THIS READY
            ReturnValue returnValues = ReturnValue.ALL_NEW;

*/
//SET THE UPDATEITEMREQUEST
      UpdateItemRequest updateItemRequest = new UpdateItemRequest()
                    .withTableName("your-table-name")
                    //KEYS DEFINED ABOVE                        
                    .withKey(key)
                    //SET WHERE TO UPDATE
                    .withUpdateExpression("set attr1 = :val1, attr2 = :val2")
                .withExpressionAttributeValues(expressionAttributeValues)
                   //INDICATE TO RETURN UPDATED ITEM                     
                  .withReturnValues(returnValues);
   //GET THE RESULT OF YOUR UPDATE AND EXECUTE IT
     UpdateItemResult result = your-dynamo-client.updateItem(updateItemRequest);
    //convert it to a string                
     Gson gson = new Gson();
     String x = gson.toJson(result);
    //Check it out                
     Log.e("RESULT :",x);

欲了解更多信息，我详细阐述了this要点。