向dynamoDB添加多个值

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，那么我要在DynamoDB中添加4行。 对于“ n”个接收值，应添加其中的“ n”行。

我遍历了数组，但仍然仅将最新数据设置为项目，并且我只能保存一行。 即，每个数组的最后一个值。

我该如何实现。 请帮我。

@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());
            }
 }

这是我的记录仪：

 ======================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

但是我只能保存一套。

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？ 我觉得您可能会一遍又一遍地覆盖同一项目。

如果表具有哈希键，则每个项目在该列中必须具有唯一的值。 如果表具有哈希/范围键，则多个项目在“哈希”列中可以具有相同的值，但它们的范围值必须不同。 更多细节在这里 。

Answer 2

除了@readyornot的答案，我还可以通过从foreach循环更改为for循环来解决。 这是代码，

//Table name: Score
//Since array size of all parameters will be same as they are dependent on each other, 
//for eg: 5 scores has 5 latitudes & 5 longitudes etc, 
//I got the size of array and looped that many no.of times.

                Score item = null;  
                for(int i=0; i<score.length; i++)
                {
                    long gen_timestamp = Calendar.getInstance().getTimeInMillis();
                    client = DynamoDBConfig.getAmazonDBClient();
                    DynamoDBMapper mapper = new DynamoDBMapper(client);
                    item = new Score();
                    item.setGen_t(gen_timestamp);
                    slf4jLogger.info(i+" Saving gen_timestamp: "+gen_timestamp);
                    item.setDevice_model(device_model);
                    slf4jLogger.info(i+" Saving device_model: "+device_model);
                    item.setApi_key(api_key);
                    slf4jLogger.info(i+" Saving api_key: "+api_key);
                    item.setUser_id(user_id);
                    slf4jLogger.info(i+" Saving user_id: "+user_id);
                    item.setRegistrationId(registrationId);
                    slf4jLogger.info(i+" Saving registrationId: "+registrationId);
                    item.setScore(score[i]);
                    slf4jLogger.info(i+" Saving Score in /receiveUpdateStressScore: "+score[i]);
                    item.setLat(lat[i]);
                    slf4jLogger.info(i+" Saving lat in /receiveUpdateStressScore: "+lat[i]);
                    item.setLon(lon[i]);
                    slf4jLogger.info(i+" Saving lon in /receiveUpdateStressScore: "+lon[i]);
                    item.setAccuracy(accuracy[i]);
                    slf4jLogger.info(i+" Saving accuracy in /receiveUpdateStressScore: "+accuracy[i]);
                    item.setUserLocalTime(userLocalTime[i]);
                    slf4jLogger.info(i+" Saving userLocalTime in /receiveUpdateStressScore: "+userLocalTime[i]);
                    item.setUserTimezone(userTimezone);
                    slf4jLogger.info(i+" Saving userTimezone: "+userTimezone);
                    slf4jLogger.info(i+"Items Saving: "+item);
                    mapper.save(item);  
                }
                slf4jLogger.info("Score Table items: "+item);