Download file

Implemented using Spring MVC, rest service.

Display file on screen or download as attachment.

@Controller
public class FileController
{
private static final Logger log = LoggerFactory.getLogger(FileController.class);

@RequestMapping(value = "/file/{id}", method = RequestMethod.GET)
public void getFileViaAttachment(@PathVariable String id, HttpServletResponse response)
{
log.info("getFile " + id);
try
{

String content = "testing file download";
String fileName = "mojFileIzStringa.txt";
InputStream in = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));

IOUtils.copy(in, response.getOutputStream());

response.setContentType("application/text");
response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
response.flushBuffer();
}
catch (IOException e)
{
e.printStackTrace();
}
}

@RequestMapping(value = "/many", method = RequestMethod.GET)
public void getManyLinesViaAttachment(HttpServletResponse response)
{
log.info("getManyLines ");
try
{
String[] linesArrays = { "prva linija", "druga linija", "xxx linija" };
List<String> linesList = Arrays.asList(linesArrays);
String fileName = "mojFileSpunoLinija.csv";
IOUtils.writeLines(linesList, null, response.getOutputStream(), StandardCharsets.UTF_8);

response.setContentType("application/text");
response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
response.flushBuffer();
}
catch (IOException e)
{
e.printStackTrace();
}
}

// every line in new row
@RequestMapping(value = "/getFileAsItIs", method = RequestMethod.GET, produces = "text/plain")
@ResponseBody
public String getFileAsItIs()
{
log.info("getFileAsItIs ");
String[] linesArrays = { "prva linija", "druga linija", "xxx linija" };
List<String> linesList = Arrays.asList(linesArrays);
StringBuilder sb = new StringBuilder();

for (String s : linesList)
{
sb.append(s).append(System.lineSeparator());
}

return sb.toString();
}
}

Change constraint

Table simmapping has foreign key to msisdn on 2 columns msisdn and providerId.
Change key so you can do update on providerId
Database: postgres.

ALTER TABLE public.simmapping
DROP CONSTRAINT fk_simmapping_msisdn,
ADD CONSTRAINT fk_simmapping_msisdn
   FOREIGN KEY (msisdn, msisdn_providerid)
   REFERENCES msisdn(msisdn, providerid)
   ON UPDATE CASCADE;

JPA Composite Key

Create class that will represent composite key and has implemented hashCode and equals methods.

public class MsisdnCompositeKey implements Serializable
{
private static final long serialVersionUID = 1L;

private String msisdn;
private Long providerId;
.....


Class that uses this composite key needs to be annotated with @IdClass and have same fields (msisdn and providedId as in example).

@Entity
@Table(name = "MSISDN")
@IdClass(value = MsisdnCompositeKey.class)
public class Msisdn
{
private static final long serialVersionUID = 1L;

@Id
private String msisdn;
@Id
private Long providerId;

.....

Ref:
https://stackoverflow.com/questions/13032948/how-to-create-and-handle-composite-primary-key-in-jpa