spring boot file upload to amazon s3 on ubuntu

1. https://medium.com/oril/uploading-files-to-aws-s3-bucket-using-spring-boot-483fcb6f8646 
2. first sign up or login to your amazon account and create bucket in s3. then create a user and give permission ie programmatic access 
3. @Configuration
   public class S3Config {
   
       @Value("${userid.aws.access_key_id}")
       private String awsId;
   
       @Value("${userid.aws.secret_access_key}")
       private String awsKey;
      
       @Value("${userid.s3.region}")
       private String region;
   
       @Bean
       public AmazonS3 xyz(){
           System.out.println("Inside s3Client of S3Config ");
           BasicAWSCredentials awsCreds = new BasicAWSCredentials(awsId, awsKey);
           AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                                   .withRegion(Regions.fromName(region))
                                   .withCredentials(new AWSStaticCredentialsProvider(awsCreds))
                                   .build();
           return s3Client;
         }
   
   
   }
4. @Controller
   public class AController {
      
       @Autowired
       private S3Service s3service;
     
             @PostMapping("/uploadFile")
            
           
             public String uploadFile(@RequestPart(value = "xyz") MultipartFile multipartFile,Model map,HttpServletRequest request) {
                
                 System.out.println("Inside upload file of bucket controller ");
   
                 try
                 {
                     String filePath = request.getServletContext().getRealPath("/");
                                    
                     System.out.println("filePath is "+filePath);
                     File f1=new File(filePath+"/"+multipartFile.getOriginalFilename());
                     multipartFile.transferTo(f1);
                     System.out.println("f1 is "+f1);                 
                    
                     String fileName=f1.getName();
   
                  String fileUrl=s3service.uploadFile(fileName, f1);
                
                 /**
                  * we should be sure that the file has indeed been uploaded 
                  */
                   map.addAttribute("fileUrl", fileUrl);                         
                  f1.delete();
                 
                /* for rest request
                  return fileUrl;
                  */              
                 
                  return "uploadSuccess";
                 
                 }
                 catch(IOException e)
                 {
                     e.printStackTrace();
                     return e.toString();
                 }
                
           }
5. @Service
   public class S3ServicesImpl implements S3Service {
       private Logger logger = LoggerFactory.getLogger(S3ServicesImpl.class);
       /* (non-Javadoc)
        * @see com.epilen.androidPatient.service.aws.s3.S3Service#downloadFile(java.lang.String)
        */
      
   
      
       @Autowired
       private AmazonS3 s3client;
   
       @Value("${userid.s3.bucket}")
       private String bucketName;
      
       @Value("${s3.endpointUrl}")
       private String endpointUrl;
      
      
       /**
        * convert multipart to file
        * @param file
        * @return
        * @throws IOException
        */
      
      
       @Override
       public void downloadFile(String keyName) {
          
           try {
              
              System.out.println("Downloading an object");
              S3Object s3object = s3client.getObject(new GetObjectRequest(bucketName, keyName));
              System.out.println("Content-Type: "  + s3object.getObjectMetadata().getContentType());
              Utility.displayText(s3object.getObjectContent());
              logger.info("===================== Import File - Done! =====================");
              
           } catch (AmazonServiceException ase) {
               logger.info("Caught an AmazonServiceException from GET requests, rejected reasons:");
               logger.info("Error Message:    " + ase.getMessage());
               logger.info("HTTP Status Code: " + ase.getStatusCode());
               logger.info("AWS Error Code:   " + ase.getErrorCode());
               logger.info("Error Type:       " + ase.getErrorType());
               logger.info("Request ID:       " + ase.getRequestId());
           } catch (AmazonClientException ace) {
               logger.info("Caught an AmazonClientException: ");
               logger.info("Error Message: " + ace.getMessage());
           } catch (IOException ioe) {
               logger.info("IOE Error Message: " + ioe.getMessage());
           }
       }
   
       /**
        * this method will return the fileurl
        */
       @Override
       public String uploadFile(String fileName, File file) {
           System.out.println("Inside upload file of S3ServiceImpl");
           try {
                  
               s3client.putObject(new PutObjectRequest(bucketName, fileName, file));
               logger.info("===================== Upload File - Done! =====================");
              
               String fileUrl = endpointUrl + "/" + bucketName + "/" + fileName;
               return fileUrl;
              
           } catch (AmazonServiceException ase) {
               logger.info("Caught an AmazonServiceException from PUT requests, rejected reasons:");
               logger.info("Error Message:    " + ase.getMessage());
               logger.info("HTTP Status Code: " + ase.getStatusCode());
               logger.info("AWS Error Code:   " + ase.getErrorCode());
               logger.info("Error Type:       " + ase.getErrorType());
               logger.info("Request ID:       " + ase.getRequestId());
               return ase.toString();
              
           } catch (AmazonClientException ace) {
               logger.info("Caught an AmazonClientException: ");
               logger.info("Error Message: " + ace.getMessage());
               return ace.toString();
           }
       }
   
      
   }
6. public interface S3Service {
           public String uploadFile(String fileName, File file);
   }
7. 
   pom.xml entry->.   
       <dependencyManagement>
     <dependencies>
       <dependency>
         <groupId>com.amazonaws</groupId>
         <artifactId>aws-java-sdk-bom</artifactId>
         <version>1.11.327</version>
         <type>pom</type>
         <scope>import</scope>
       </dependency>
     </dependencies>
   </dependencyManagement>
   
     <dependencies>
    
      <dependency>
       <groupId>com.amazonaws</groupId>
       <artifactId>aws-java-sdk-s3</artifactId>
     </dependency>
    
      <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.2</version> 
    </dependency>
    
     the above reduces the jar size from 90 mb to 35 mb and downloads only s3 dependencies
8. application.properties entries                                                                          userid.aws.access_key_id=  userid.aws.secret_access_key=                                                                             userid.s3.bucket=
   userid.s3.region=
   s3.endpointUrl=