java - 将多个值添加到 dynamoDB

Question

我想向 DynamoDB 添加多个值。我想添加所有数据集。

例如，如果有 4 个值，则我要在 DynamoDB 中添加 4 行。对于“n”个接收值，应添加“n”行。

我循环遍历了数组，但仍然只有最新数据被设置到item中，并且我只能保存一行。即每个数组的最后一个值。

我怎样才能实现这个目标。请帮助我。

@RequestMapping(value="/receiveRequests", method=RequestMethod.POST,produces={"application/json"})
public Map<String, Object> receiveRequests(@RequestParam(value="user_id") String user_id,
                                            @RequestParam(value="device_model") String device_model, 
                                            @RequestParam(value="api_key") String api_key,
                                            @RequestParam(value="score") int[] score,
                                            @RequestParam(value="registrationId") String registrationId,
                                            @RequestParam(value="userLocalTime") String[] userLocalTime,
                                            @RequestParam(value="lat") double[] lat,
                                            @RequestParam(value="lon") double[] lon,
                                            @RequestParam(value="accuracy") float[] accuracy,
                                            @RequestParam(value="userTimezone") String userTimezone,
                                            Model model)
{
            try
            {
                AmazonDynamoDBClient client = DynamoDBConfig.getAmazonDBClient();
                DynamoDBMapper mapper = new DynamoDBMapper(client);

                slf4jLogger.info("======================Begin Saving values to DynamoDB===================================================");   
                ScoreTable item = new ScoreTable();
                for(int ScoreValue : score)
                {
                    item.setScore(ScoreValue);
                    slf4jLogger.info("Saving Score: "+ScoreValue);
                }
                item.setDevice_model(device_model);
                slf4jLogger.info("Saving device_model: "+device_model);
                item.setApi_key(api_key);
                slf4jLogger.info("Saving api_key: "+api_key);
                item.setUser_id(user_id);
                slf4jLogger.info("Saving user_id: "+user_id);
                item.setRegistrationId(registrationId);
                slf4jLogger.info("Saving registrationId: "+registrationId);
                for(double latitude : lat)
                {
                    item.setLat(latitude);
                    slf4jLogger.info("Saving latitude: "+latitude);
                }
                for(double longitude : lon)
                {
                    item.setLon(longitude);
                    slf4jLogger.info("Saving longitude: "+longitude);
                }
                for(float accuracyValue : accuracy)
                {
                    item.setAccuracy(accuracyValue);
                    slf4jLogger.info("Saving accuracyValue: "+accuracyValue);
                }
                for(String userlocaltym:userLocalTime)
                {
                    item.setUserLocalTime(userlocaltym);
                    slf4jLogger.info("Saving userlocaltym: "+userlocaltym);
                }
                item.setUserTimezone(userTimezone);
                slf4jLogger.info("Saving userTimezone"+userTimezone);
                mapper.save(item);
                slf4jLogger.info("StressScore Table items: "+item);
            }           
            catch(AmazonServiceException ase)
            {
                //ase.printStackTrace();
                slf4jLogger.error(ase);
                slf4jLogger.error(ase.getMessage());
                slf4jLogger.error(ase.getStackTrace());
            }
            catch (Exception e)
            {
                //e.printStackTrace();
                slf4jLogger.error(e);
                slf4jLogger.error(e.getMessage());
                slf4jLogger.error(e.getStackTrace());
            }
 }

这是我的记录器:

 ======================Begin Saving values to DynamoDB===================================================
Saving Score: 86
Saving Score: 92
Saving Score: 32
Saving Score: 65

Saving device_model: Nexus S
Saving api_key: testApp
Saving user_id: 10f353a0-c6da-44ee-a9cb
Saving registrationId: APA91bFOz1lCFr1dT_s-HH-TatpF1XOIQ6GF846EMfmTjd_x-wARKy1zyEwr86UXfL9K1Xm8_PHpOKVuxmUXLKXHVKurXwe75EPmnBJolvS0

Saving latitude: 12.9563
Saving latitude: 12.9565
Saving latitude: 12.9567
Saving latitude: 12.9511

Saving longitude: 12.9563
Saving longitude: 12.9562
Saving longitude: 12.9563
Saving longitude: 12.912

Saving accuracyValue: 694.0
Saving accuracyValue: 611.0
Saving accuracyValue: 612.0
Saving accuracyValue: 613.0

Saving userlocaltym: 11-02-2015 11:20:25
Saving userlocaltym: 11-02-2015 11:21:26
Saving userlocaltym: 11-02-2015 11:22:25
Saving userlocaltym: 11-02-2015 11:25:25

Saving userTimezoneAsia/Calcutta

但我只能保存一套。

Score Table items: Score [user_id=10f353a0-c6da-44ee-a9cb, device_model=Nexus S, api_key=testApp, gen_t=1436175254608, score=98, registrationId=APA91bFOz1lCFr1dT_s-HH-TatpF1XOIQ6GF846EMfmTjd_x-wARKy1zyEwr86UXfL9K1Xm8_PHpOKVuxmUXLKXHVKurXwe75EPmnBJolvS0, lat=12.9511, lon=12.912, accuracy=613.0, userLocalTime=11-02-2015 11:25:25, userTimezone=Asia/Calcutta]
======================End Saving values to DynamoDB===================================================

Answer 1

DynamoDB 分数表上的哈希键(以及组合键的范围)是什么？我有一种感觉，您可能会一遍又一遍地覆盖同一个项目。

如果表具有哈希键，则每个项目在该列中必须具有唯一值。如果表有 Hash/Range 键，则多个项在 Hash 列中可以具有相同的值，但它们的 Range 值必须不同。更多详情here .