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Convert Java object list to entity list

I have multiple objects in my array using . If I then send this to my Spring Boot backend with axios and output the FormData beforehand, I get the following image. That fits. In the backend, however, I need this list of objects as an entity. In this case, of type List. Do I do that?
Frontend code:
let data = new FormData();
...
data.append("zugeordnet", JSON.stringify(personNamen));
await axios.post("/neuerEintrag", data,...)
React:
Backend:
#PostMapping("/neuerEintrag")
public String neuerEintrag(HttpServletRequest req,#RequestParam("zugeordnet") List<?> zugeordnet,..) {
List<User> userListe = (List<User>) zugeordnet;
for(User inListe : userListe) //ERROR here
{
System.out.println("USER :" + inListe);
}
...
}
java.lang.ClassCastException: class java.lang.String cannot be cast to class com.home.calendar.User.User
UPDATE
For completeness, here is the user entity and the complete method for a new entry.
#PostMapping("/neuerEintrag")
public String neuerEintrag(HttpServletRequest req, #RequestParam("beschreibung") String beschreibung,
#RequestParam("datum") Date datum, #RequestBody List<User> zugeordnet,
#RequestBody List<Freunde> kontaktAuswahl, #RequestParam("neuAlt") String neuAlt,
#RequestParam("kalenderId") int kalenderId) { }
The User Entity:
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String name;
#JsonIgnoreProperties("user")
#OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "user")
private List<Kalender> kalenderEinträge;
public User() {
super();
// TODO Auto-generated constructor stub
}
public User(String name, List<Kalender> kalenderEinträge) {
super();
this.name = name;
this.kalenderEinträge = kalenderEinträge;
}
public List<Kalender> getKalenderEinträge() {
return kalenderEinträge;
}
[getter/setter]

Spring can't parse an unknown object.
To get it work, I suggest a new class for the "request".
#Data // lombok - this generates getter/setters/equals/hashcode for you
public class NeuerEintragRequest {
private List<User> zugeordnet;
private String beschreibung;
private int kalendarId;
// and your others fields
}
The controller can now use very type-safe objects.
#PostMapping("/neuerEintrag")
public String neuerEintrag(#RequestBody NeuerEintragRequest request) {
for(User user : request.getUserlist()) {
// a logging framework is a lot better. Try to use log4j or slf4j.
log.info("USER: {}", user);
}
...
}
Typescript
Let axios handle the typing and serializing. See this tutorial: https://masteringjs.io/tutorials/axios/post-json
To post all the needed data, you can create a new object.
// no formdata - just send the object
const data = { zugeordnet: personNamen, kalendarId: 123, beschreibung: 'abc' };
await axios.post("/neuerEintrag", data);
You can also create a interface in typescript, but this is going to much for a stackoverflow-answer. Try to learn more about spring and typescript.

Based on question & comments ,
your front end call data.append("zugeordnet", JSON.stringify(personNamen)); is converting your object to List<String> instead of List<User>.
So you can transform this List<String> to List<User> in your postMapping:
#PostMapping("/neuerEintrag")
public String neuerEintrag(HttpServletRequest req,#RequestParam("zugeordnet") List<?> zugeordnet,..) {
ObjectMapper mapper=new ObjectMapper();
for(String str:zugeordnet){
System.out.println(mapper.readValue(str, User.class));
}
...
}

How to loop through a list payload and insert into database as individual row items in Springboot?

I am trying to insert items in a list in a database as single values in rows with the name of the sender. I am able to send the payload and insert into a single row with the user detailst. How can I loop through the payload sent and insert all the items into individual rows? I have tried to look for examples no luck. So far I can only insert as a single row in the database
this is the payload
{"labsigned":["234568","234567","2345678","2344556","12335677","2345677","234556","234545"]}
My controller
#RequestMapping(path = "/labreport/createrordispatched", method = RequestMethod.POST)
public ResponseEntity<?> createDispatched(#RequestBody Dispatched dispatched){
if(labDashboardService.createDispatched(dispatched)) {
return ResponseEntity.status(HttpStatus.CREATED).body(true);
}
return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(false);
}
My Service
public boolean createDispatched(Dispatched dispatched) {
dispatched.setCreatedBy(getCurrentUserEmail());
dispatched.setDateCreated(System.currentTimeMillis());
Dispatched ticket = new Dispatched(
dispatched.getCreatedBy(),
dispatched.getDateCreated(),
dispatched.getlabsigned()
);
dispatchedRepository.save(ticket);
return false;
}
My Model
#Entity
#Table(name = "DISPATCHED")
public class Dispatched {
private String id;
private String labsigned;
private Long dateCreated;
private String createdBy;
public Dispatched(){}
public Dispatched(String createdBy, Long dateCreated, String labsigned){
this.labsigned = rorlabsigned;
this.dateCreated = dateCreated;
this.createdBy = createdBy;
}

Assuming that you were able to insert all labsigned in the payload into one single row with the code you mentioned in the question, You should iterate dispatched.labsigned and insert one by one as rows to accomplish what you need. And returning false at the end of method createDispatched will always return HttpStatus.BAD_REQUEST even though the records are successfully saved in the DB, so you might need to change it to return true.
public boolean createDispatched(Dispatched dispatched) {
List<Dispatched> newTickets = new ArrayList<>();
dispatched.setCreatedBy(getCurrentUserEmail());
dispatched.setDateCreated(System.currentTimeMillis());
for(String labSigned:dispatched.getlabsigned()){
Dispatched ticket = new Dispatched(
dispatched.getCreatedBy(),
dispatched.getDateCreated(),
labSigned
);
newTickets.add(ticket);
}
dispatchedRepository.saveAll(newTickets);
return true;
}

Just send in a list of those values. Shouldn't have to be wrapped in a named field on an object. Just send it in as a json array like ["234568","234567","2345678","2344556","12335677","2345677","234556","234545"]. In your controller method, body don't pass it in as Dispatched but instead a List and then just loop through those creating a list of Dispatch objects and then using saveAll in the repository passing in the newly created Dispatched list.
Update: Example without actually compiling. Should be good enough for the example. Also using lombok to make it easier to read and a few other updates.
#AllArgsConstructor
#FieldDefaults(level = AccessLevel.PRIVATE, makeFinal = true)
#RestController
public class DispatchController {
DispatchedEntityFactory dispatchedEntityFactory;
DispatchedRepository dispatchedRepository;
#PostMapping("/labreport/createrordispatched")
public ResponseEntity<Boolean> createDispatched(DispatchedRequest dispatchedRequests){
List<DispatchedEntity> dispatchedEntities = dispatchedEntityFactory.creatMultipleFromDispatchRequest(dispatchedRequests);
if(CollectionUtils.isEmpty(dispatchedEntities)) {
return ResponseEntity.badRequest().body(false);
}
dispatchedRepository.saveAll(dispatchedEntities);
return ResponseEntity.ok(true);
}
}
#Value
public class DispatchedRequest {
String id;
List<String>labsigned;
Long dateCreated;
String createdBy;
}
#Entity
#Table(name = "DISPATCHED")
#Data
#FieldDefaults(level = AccessLevel.PRIVATE)
public class DispatchedEntity {
String id;
String labsigned;
Long dateCreated;
String createdBy;
}
#Component
public class DispatchedEntityFactory {
public List<DispatchedEntity> creatMultipleFromDispatchRequest(final DispatchedRequest dispatchedRequest) {
List<DispatchedEntity> dispatchedEntities = new ArrayList<DispatchedEntity>();
for(String labsignature : dispatchedRequest.getLabsigned()) {
DispatchedEntity dispatchedEntity = new DispatchedEntity(dispatchedRequest.getId(),labsignature, dispatchedRequest.getDateCreated(), dispatchedRequest.getCreatedBy());
dispatchedEntities.add(dispatchedEntity);
}
return dispatchedEntities;
}
}

Identify constraint name that trigger DataIntegrityViolationException

I am stuck with a issue of identify which constraint triggers DataIntegrityViolationException. I have two unique constraints: username and email but I have no luck trying to figure it out.
I have tried to get the root cause exception but I got this message
Unique index or primary key violation: "UK_6DOTKOTT2KJSP8VW4D0M25FB7_INDEX_4 ON PUBLIC.USERS(EMAIL) VALUES ('copeland#yahoo.com', 21)"; SQL statement:
insert into users (id, created_at, updated_at, country, email, last_name, name, password, phone, sex, username) values (null, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) [23505-193]
Reading the error I know email constraint triggers the validation but I want to return to the user something like:
{type: ERROR, message: "The email already exist"}
I have read in other post and people handle it looking for a constraint name into the exception(eg, users_unique_username_idx) and display a proper message to the user. But I couldn't get that type of constraint name
Maybe I am missing a configuration. I am using:
Spring Boot 1.5.1.RELEASE, JPA, Hibernate and H2
My application.properties
spring.jpa.generate-ddl=true
User.class:
#Entity(name = "users")
public class User extends BaseEntity {
private static final Logger LOGGER = LoggerFactory.getLogger(User.class);
public enum Sex { MALE, FEMALE }
#Id
#GeneratedValue
private Long id;
#Column(name = "name", length = 100)
#NotNull(message = "error.name.notnull")
private String name;
#Column(name = "lastName", length = 100)
#NotNull(message = "error.lastName.notnull")
private String lastName;
#Column(name = "email", unique = true, length = 100)
#NotNull(message = "error.email.notnull")
private String email;
#Column(name = "username", unique = true, length = 100)
#NotNull(message = "error.username.notnull")
private String username;
#Column(name = "password", length = 100)
#NotNull(message = "error.password.notnull")
#JsonProperty(access = JsonProperty.Access.WRITE_ONLY)
private String password;
#Enumerated(EnumType.STRING)
private Sex sex;
#Column(name = "phone", length = 50)
private String phone;
#Column(name = "country", length = 100)
#NotNull(message = "error.country.notnull")
private String country;
public User() {}
// Getters and setters
}
ControllerValidationHandler.class
#ControllerAdvice
public class ControllerValidationHandler {
private final Logger LOGGER = LoggerFactory.getLogger(ControllerValidationHandler.class);
#Autowired
private MessageSource msgSource;
private static Map<String, String> constraintCodeMap = new HashMap<String, String>() {
{
put("users_unique_username_idx", "exception.users.duplicate_username");
put("users_unique_email_idx", "exception.users.duplicate_email");
}
};
// This solution I see in another stackoverflow answer but not work
// for me. This is the closest solution to solve my problem that I found
#ResponseStatus(value = HttpStatus.CONFLICT) // 409
#ExceptionHandler(DataIntegrityViolationException.class)
#ResponseBody
public ErrorInfo conflict(HttpServletRequest req, DataIntegrityViolationException e) {
String rootMsg = ValidationUtil.getRootCause(e).getMessage();
LOGGER.info("rootMessage" + rootMsg);
if (rootMsg != null) {
Optional<Map.Entry<String, String>> entry = constraintCodeMap.entrySet().stream()
.filter((it) -> rootMsg.contains(it.getKey()))
.findAny();
LOGGER.info("Has entries: " + entry.isPresent()); // false
if (entry.isPresent()) {
LOGGER.info("Value: " + entry.get().getValue());
e=new DataIntegrityViolationException(
msgSource.getMessage(entry.get().getValue(), null, LocaleContextHolder.getLocale()));
}
}
return new ErrorInfo(req, e);
}
The response at this moment is:
{"timestamp":1488063801557,"status":500,"error":"Internal Server Error","exception":"org.springframework.dao.DataIntegrityViolationException","message":"could not execute statement; SQL [n/a]; constraint [\"UK_6DOTKOTT2KJSP8VW4D0M25FB7_INDEX_4 ON PUBLIC.USERS(EMAIL) VALUES ('copeland#yahoo.com', 21)\"; SQL statement:\ninsert into users (id, created_at, updated_at, country, email, last_name, name, password, phone, sex, username) values (null, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) [23505-193]]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement","path":"/users"}
UPDATE
This is my service layer that handle my persistence operations
MysqlService.class
#Service
#Qualifier("mysql")
class MysqlUserService implements UserService {
private UserRepository userRepository;
#Autowired
public MysqlUserService(UserRepository userRepository) {
this.userRepository = userRepository;
}
#Override
public List<User> findAll() {
return userRepository.findAll();
}
#Override
public Page<User> findAll(Pageable pageable) {
return userRepository.findAll(pageable);
}
#Override
public User findOne(Long id) {
return userRepository.findOne(id);
}
#Override
public User store(User user) {
return userRepository.save(user);
}
#Override
public User update(User usr) {
User user = this.validateUser(usr);
return userRepository.save(user);
}
#Override
public void destroy(Long id) {
this.validateUser(id);
userRepository.delete(id);
}
private User validateUser(User usr) {
return validateUser(usr.getId());
}
/**
* Validate that an user exists
*
* #param id of the user
* #return an existing User
*/
private User validateUser(Long id) {
User user = userRepository.findOne(id);
if (user == null) {
throw new UserNotFoundException();
}
return user;
}
}
Update #2
Repo to reproduce the issue https://github.com/LTroya/boot-users. I commented my handler on ValidationExceptionHandler.class in order to see the exception.
Send twice json at Json to test on Readme.md to POST /users/

What you want to do is rather than specify the unique column requirement on the #Column annotation, you can actual define those with names on the #Table annotation that JPA provides to have further control of those constraints.
#Entity
#Table(uniqueConstraints = {
#UniqueConstraint(name = "UC_email", columnNames = { "email" } ),
#UniqueConstraint(name = "UC_username", columnNames = " { "userName" } )
})
There are now two ways for handling the exception:
In the controller
You could elect to place the parsing logic in your controller and simply catch the DataIntegrityException that spring throws and parse it there. Something like the following pseudo code:
public ResponseBody myFancyControllerMethod(...) {
try {
final User user = userService.myFactoryServiceMethod(...);
}
catch ( DataIntegrityException e ) {
// handle exception parsing & setting the appropriate error here
}
}
The ultimate crux with this approach for me is we've moved code to handle persistence problems up two layers rather than the layer immediately above the persistence tier. This means should we have multiple controllers which need to handle this scenario we either find ourselves doing one of the following
Introduce some abstract base controller to place the logic.
Introduce some helper class with static methods we call for reuse.
Cut-n-paste the code - Yes this happens more than we think.
Placing the code in the presentation tier also introduces concerns when you need to share that service with other consumer types that may not be actually returning some type of html view.
This is why I recommend pushing the logic down 1 more level.
In the service
This is a cleaner approach because we push the validation of the constraint handling to the layer above the persistence layer, which is meant to ultimately be where we handle persistence failures. Not only that, our code actually documents the failure conditions and we can elect either to ignore or handle them based on context.
The caveat here is that I'd recommend you create specific exception classes that you throw from your service tier code in order to identify the unique constraint failures and throw those after you have parsed the ConstraintViolationException from Hibernate.
In your web controller, rest controller, or whatever other consumer that is calling into your service, you simply need to catch the appropriate exception class if necessary and branch accordingly. Here's some service pseudo code:
public User myFancyServiceMethod(...) {
try {
// do your stuff here
return userRepository.save( user );
}
catch( ConstraintViolationException e ) {
if ( isExceptionUniqueConstraintFor( "UC_email" ) ) {
throw new EmailAddressAlreadyExistsException();
}
else if ( isExceptionUniqueConstraintFor( "UC_username" ) ) {
throw new UserNameAlreadyExistsException();
}
}
}

You can specify unique constraints separately but you'd need to that on the entity level like
#Entity(name = "users")
#Table(name = "users", uniqueConstraints = {
#UniqueConstraint(name = "users_unique_username_idx", columnNames = "username"),
#UniqueConstraint(name = "users_unique_email_idx", columnNames = "email")
})
public class User extends BaseEntity { ... }

hibernate partially update when entity parsed with json

I have a pretty simple mysql record like this:
+------+-------+-----------+
| id | name | password |
+------+-------+-----------+
| 1 | John | d0c91f13f |
+------+-------+-----------+
... ... ...
And here is its hibernate entity; nothing fancy
#Entity
#Table(name = "user", schema = "", catalog = "trade")
public class UserEntity{
private long id;
private String name;
private String password;
#Id
#Column(name = "id")
public long getId(){
return id;
}
public void setId(long id){
this.id = id;
}
#Column(name = "name")
public String getName(){
return name;
}
public void setName(String name){
this.name = name;
}
#Column(name = "password")
public String getPasswrod(){
return password;
}
public void setPassword(String password){
this.password = password;
}
}
For convenience, I use Gson to parse the entity from json string which front-end passed in.
The json string for the record is like this:
{"id":1, "name":"John", "password":"d0c91f13f"}
then userEntity will be parsed from the json String:
UserEntity userEntity = gson.fromJson(userJson, UserEntity.class);
I can insert or update the user with Session.save(userEntity) and Session.update(userEntity).
If every field is contained in the json string, then things seemed goes as expected.
But when some field, such as password is omitted:
{"id":1, "name":"John Smith"}
which indicated that I should make a partial update and leave the omitted field not modified, things went wrong. Because
the parsing procedure will set password to Null. and update it to the database.
So, is there a solution to partially update the record in this case?
Going through every field and setting fields one by one will be the last option; anything other than that?
Thanks in advance.

If you know a particular entry exists, then fetching the entry before updating would fill the object with the existing values and you'd only change the values your Json provided. This avoids null updates like you describe.
If, however, the entry is new, then whatever is missing in the Json will be passed as null to the database.

1,Suppose you can deserialized srcUserEntity by:
UserEntity srcUserEntity = gson.fromJson(userJson, UserEntity.class);
2, You can leverage spring's BeanUtil's copy properties method.
BeanUtils.copyProperties(srcUserEntity, desUserEntity, SpringBeanUtil.getNullPropertyNames(srcUserEntity));
3, In your Dao layer, just fetch the model from Database first, then update the properties needs to be updated only, lastly update. Refer to codes as below:
Session currentSession = sessionFactory.getCurrentSession();
UserEntity modelInDB = (UserEntity)currentSession.get(UserEntity.class, user.getId());
//Set properties that needs to update in DB, ignore others are null.
BeanUtils.copyProperties(productStatusModelForPatch, modelInDB, SpringBeanUtil.getNullPropertyNames(productStatusModelForPatch));
currentSession.update(modelInDB);
4, for getNullPropertyNames() method, please refer to [How to ignore null values using springframework BeanUtils copyProperties? (Solved)
public static String[] getNullPropertyNames (Object source) {
final BeanWrapper src = new BeanWrapperImpl(source);
java.beans.PropertyDescriptor[] pds = src.getPropertyDescriptors();
Set<String> emptyNames = new HashSet<String>();
for(java.beans.PropertyDescriptor pd : pds) {
Object srcValue = src.getPropertyValue(pd.getName());
if (srcValue == null) emptyNames.add(pd.getName());
}
String[] result = new String[emptyNames.size()];
return emptyNames.toArray(result);
}
// then use Spring BeanUtils to copy and ignore null
public static void myCopyProperties(Object, src, Object target) {
BeanUtils.copyProperties(src, target, getNullPropertyNames(src))
}

Spring data mongodb query converts String to ObjectId automatically

The title might not be super clear, here the problem
I'm executing an update in this form:
db.poi.update({
_id: ObjectId("50f40cd052187a491707053b"),
"votes.userid": {
"$ne": "50f5460d5218fe9d1e2c7b4f"
}
},
{
$push: {
votes: {
"userid": "50f5460d5218fe9d1e2c7b4f",
"value": 1
}
},
$inc: { "score":1 }
})
To insert a document in an array only if there isn't one with the same userid (workaround because unique indexes don't work on arrays). The code works fine from mongo console. From my application I'm using this:
#Override
public void vote(String id, Vote vote) {
Query query = new Query(Criteria.where("_id").is(id).and("votes.userid").ne(vote.getUserid()));
Update update = new Update().inc("score", vote.getValue()).push("votes", vote);
mongoOperations.updateFirst(query, update, Poi.class);
}
This works fine if as "userid" I use a String that can't be a mongo ObjectId, but if I use the string in the example, the query executed translates like this (from mongosniff):
update flags:0 q:{ _id: ObjectId('50f40cd052187a491707053b'), votes.userid: { $ne: ObjectId('50f5460d5218fe9d1e2c7b4f') } } o:{ $inc: { score: 1 }, $push: { votes: { userid: "50f5460d5218fe9d1e2c7b4f", value: 1 } } }
The string is now an Objectid. Is this a bug? BasicQuery do the same thing. The only other solution I see is to use ObjectId instead of String for all classes ids.
Any thoughts?
UPDATE:
This is the Vote class
public class Vote {
private String userid;
private int value;
}
This is the User class
#Document
public class User {
#Id
private String id;
private String username;
}
This is the class and mongo document where I'm doing this update
#Document
public class MyClass {
#Id
private String id;
#Indexed
private String name;
int score
private Set<Vote>votes = new HashSet<Vote>();
}
As Json
{
"_id" : ObjectId("50f40cd052187a491707053b"),
"name" : "Test",
"score" : 12,
"votes" : [
{
"userid" : "50f5460d5218fe9d1e2c7b4f",
"value" : 1
}
]
}
Userid in votes.userid is pushed as String, but the same String is compared as an ObjectId in the $ne

It seems to me the problem can be described like this: if you use String in your classes in place of an ObjectId, if you want to use those ids as references (no dbrefs) in other documents (and embedded documents), they are pushed as String (it's ok because they are Strings). It's fine because spring data can map them again to objectid, but it's not fine if you do a query like the one I mentioned; the field is converted to an objectid in the comparison (the $ne operator in this case) but is considered as a string in the embedded document. So, to wrap up, in my opinion the $ne operator in this case should consider the field a String.
My solution was to write a custom converter to store the String as an objectid in the documents where the id is a reference
public class VoteWriteConverter implements Converter<Vote, DBObject> {
#Override
public DBObject convert(Vote vote) {
DBObject dbo = new BasicDBObject();
dbo.put("userid", new ObjectId(vote.getUserid()));
dbo.put("value", vote.getValue());
return dbo;
}
}