I am using hibernate to persist my data. It's a financial application and I am having a hard time persisting the most fundamental entity of the application which is 'Money'. I was using JodaMoney but it's immutable so I am not able to find a good way to persist it. And without persisting my money to database, there is no point of making the application. What would I do with the immutability when I can't even store the state of my object?
Then I started creating my own 'Money'(fields as BigDecimal amount and java.util.Currency for currency), I wanted to use 'Currency' of java.util . But, that doesn't have a public constructor so hibernate can not persist that.
Please guide me on how to deal with this?
EDIT1: The code for most basic class:
#Entity
public class BasicMoney {
#Embedded
#Id
private BigDecimal amount;
#Embedded
private Currency currency;
//getters and setters, other methods
}
Now, when I make an object of this class and try to store it into database, it doesn't work. Hibernate throws:
org.hibernate.InstantiationException: No default constructor for entity: : java.util.Currency
So, this is the problem which I am facing.
You could use a workaround
#Embedded
String currency; //store data as a string
public void setCurrency(Currency currency) {
this.currency = currency.getCurrencyCode(); //conversion to an actual currency
}
public Currency getCurrency() {
return Currency.getInstance(currency); //conversion to an actual currency
}
Instead of dealing with a currency string and an amount, teach Hibernate about your type instead. That way you would have:
private Money amount;
instead of
private BigDecimal amount;
private String currency;
so you don't need to convert all over the place.
Here's how I do it:
1) Instead of JodaMoney, use JavaMoney, the JSR-354 project that is expected to be included in Java 9. If you want to stick to JodaMoney, you don't need step #3 below.
2) Add this UserType library to your classpath
3) Create this simple class:
public class CustomPersistentMoneyAmountAndCurrency extends AbstractMultiColumnUserType<MonetaryAmount> {
private static final ColumnMapper<?, ?>[] COLUMN_MAPPERS = new ColumnMapper<?, ?>[] { new CustomStringColumnCurrencyUnitMapper(), new BigDecimalBigDecimalColumnMapper() };
private static final String[] PROPERTY_NAMES = new String[]{ "currency", "number" };
#Override
protected ColumnMapper<?, ?>[] getColumnMappers() {
return COLUMN_MAPPERS;
}
#Override
protected Money fromConvertedColumns(Object[] convertedColumns) {
CurrencyUnit currencyUnitPart = (CurrencyUnit) convertedColumns[0];
BigDecimal amountPart = (BigDecimal) convertedColumns[1];
return Money.of(amountPart, currencyUnitPart);
}
#Override
protected Object[] toConvertedColumns(MonetaryAmount value) {
return new Object[] { value.getCurrency(), value.getNumber().numberValue(BigDecimal.class) };
}
#Override
public String[] getPropertyNames() {
return PROPERTY_NAMES;
}
}
4) Now wherever you want to use this in your Entities you would do:
#TypeDefs(value = {
#TypeDef(name = "moneyAmountWithCurrencyType", typeClass = CustomPersistentMoneyAmountAndCurrency.class)
})
#Entity
#Table(name = "account_entry")
public class AccountEntry {
private Money referenceMoney;
...
#Basic( optional = false )
#Columns(columns = {
#Column( name = "reference_money_currency", nullable = false, length = 3 ),
#Column( name = "reference_money", nullable = false )
})
#Type(type = "moneyAmountWithCurrencyType")
public Money getReferenceMoney() {
return this.referenceMoney;
}
}
And that's it. You will get strong typing all throughout.
Hibernate does support java.util.Currency natively.
https://docs.jboss.org/hibernate/orm/3.6/reference/en-US/html/types.html#types-basic-value-currency
Sorry for the late answer, but I didn´t see this option as an answer and I think is pretty elegant. You can use a JPA converter with autoapply:
#Converter(autoApply = true)
public class CurrencyConverter implements AttributeConverter<Currency, String> {
#Override
public String convertToDatabaseColumn(Currency currency) {
return currency.getCurrencyCode();
}
#Override
public Currency convertToEntityAttribute(String currencyCode) {
return Currency.getInstance(currencyCode);
}
}
Related
I have a composite primary key made of planId and planDate, when the user gives me both this attributes I cant find a way to retrieve it from my Repo. Should findById work like this?
public Plans assignPlansToMeds(Long id, Long planId, Date planDate) {
Set<Meds> medsSet = null;
Meds meds = medsRepo.findById(id).get();
Plans plans = plansRepo.findById(planId, planDate).get();
medsSet = plans.getAssignedMeds();
medsSet.add(meds);
plans.setAssignedMeds(medsSet);
return plansRepo.save(plans);
}
My Primary Key:
#Data
#AllArgsConstructor
#NoArgsConstructor
#EqualsAndHashCode
#Embeddable
public class PlansPKId implements Serializable {
private long planId;
private Date planDate; // format: yyyy-mm-dd
}
Plans entity:
#Data
#AllArgsConstructor
#NoArgsConstructor
#Entity
#Table(name = "plans")
public class Plans {
#EmbeddedId
private PlansPKId plansPKId;
#Column
private String planName;
#Column
private String weekday;
#ManyToMany
#JoinTable(name = "Plan_Meds", joinColumns = {
#JoinColumn(name = "planDate", referencedColumnName = "planDate"),
#JoinColumn(name = "planId", referencedColumnName = "planId") }, inverseJoinColumns = #JoinColumn(name = "id"))
private Set<Meds> assignedMeds = new HashSet<>();
}
where I ask for the planId and planDate:
#PutMapping("/medicine/{id}/assignToPlan/{planId}/date/{plandate}")
public Plans assignMedToPlan(#PathVariable Long id, #PathVariable Long planId, #PathVariable Date planDate){
return assignService.assignPlansToMeds(id, planId, planDate);
}
The Spring JpaRepository only allows one type as the ID-type, as can be seen in the javadoc. Therefore, findById will never accept two arguments.
You need to define your repository with your EmbeddedId-type as ID-type as follows:
#Repository
public interface PlansRepository extends JpaRepository<Plans, PlansPKId> {
}
You can then call the findById method as follows:
Plans plans = plansRepo.findById(new PlansPKId(planId, planDate))
.orElseThrow(PlansNotFoundException.idAndDate(planId, planDate));
If you dont want to create a new PlansPKId instance for every query, you could also define a repository method as follows and let Spring derive the query based on the method name:
Optional<Plans> findByPlansPKIdPlanIdAndPlansPKIdPlanDate(long planId, Date planDate);
If you don't like to have a cumbersome method name you could as well define a JPQL query and name the method as you like:
#Query("select p from Plans p where p.plansPKId.planId = :planId and p.plansPKId.planDate = :planDate")
Optional<Plans> findByCompositeId(#Param("planId) long planId, #Param("planDate") Date planDate);
On a side note, I strongly encourage you to use LocalDate, LocalDateTime or ZonedDateTime (depending on your needs) instead of the legacy Date class.
Moreover, you shouldn't call get() on an Optional without checking if it is present. I recently wrote an answer on SO describing how you can create an elegant error handling. If you stuck to my example, you had to create a NotFoundException and then create the PlansNotFoundException which extends NotFoundException. by this means, everytime when a PlansNotFoundException is thrown in thread started by a web request, the user would receive a 404 response and a useful message if you implement it like this:
public abstract class NotFoundException extends RuntimeException {
protected NotFoundException(final String object, final String identifierName, final Object identifier) {
super(String.format("No %s found with %s %s", object, identifierName, identifier));
}
protected NotFoundException(final String object, final Map<String, Object> identifiers) {
super(String.format("No %s found with %s", object,
identifiers.entrySet().stream()
.map(entry -> String.format("%s %s", entry.getKey(), entry.getValue()))
.collect(Collectors.joining(" and "))));
}
}
public class PlansNotFoundException extends NotFoundException {
private PlansNotFoundException(final Map<String, Object> identifiers) {
super("plans", identifiers);
}
public static Supplier<PlansNotFoundException> idAndDate(final long planId, final Date planDate) {
return () -> new PlansNotFoundException(Map.of("id", id, "date", date));
}
}
For the Meds case:
public class MedsNotFoundException extends NotFoundException {
private MedsNotFoundException(final String identifierName, final Object identifier) {
super("meds", identifierName, identifier);
}
public static Supplier<MedsNotFoundException> id(final long id) {
return () -> new MedsNotFoundException("id", id);
}
}
Meds meds = medsRepo.findById(id).orElseThrow(MedsNotFoundException.id(id));
I'm not sure how to phrase the question title to be honest, if someone has a suggestion, please let me know.
My use case is this, I have an entity with an account property like so (this is cleaned up to avoid clutter):
#Entity
#Table(name = "report_line", schema = "public")
public class ReportLine extends BaseReportLine {
#ManyToOne
#JoinColumn(name = "report_id")
private Report report;
#ManyToOne
#JoinColumn(name = "account_id")
private Account account;
}
But a DTO that only has an account id / different properties:
public class ImportLineDto {
public String groupName;
public Integer position;
public Integer parentPosition;
public String accountId;
public String name;
public BigDecimal amount;
public List<ImportLineDto> lines = new ArrayList<>();
}
I need to go through / flatten all lines so I can save it to a JPA repository, but there are 2 issues:
Is there a way to create the table line object using the accountId only, without having to look up the account for each line, as that will add a massive amount of unnecessary db calls.
What should I do with the 'lines' on each table object after flattening? Should I set them to null / empty list?
Is there a better way to do this? For once I can actually make changes to the code
Here is what I have so far:
private void saveReport(ImportedResult result) {
Report report = new Report();
...
report.setLines(getReportLinesFromDtoLines(result.lineItems.lines));
ReportRepository.saveAndFlush(report);
}
private List<ReportLine> getReportLinesFromDtoLines(ImportLineDto lines) {
List<ImportLineDto> flatLines = flatMapRecursive(lines).collect(Collectors.toList());
List<ReportLine> reportLines = new ArrayList<>();
for(ImportLineDto line: flatLines) {
ReportLine reportLine = new ReportLine();
reportLine.setItemText(line.name);
reportLine.setAmount(line.amount);
reportLine.setAccount(???);
// how do I set the 'Account' property using the id only, without looking up each account?
reportLines.add(reportLine);
}
return ReportLines;
}
public Stream<ImportLineDto> flatMapRecursive(ImportLineDto item) {
if (item.lines == null) {
return Stream.empty();
}
return Stream.concat(Stream.of(item), item.lines.stream()
.flatMap(this::flatMapRecursive));
}
Follow up:
Just to throw a wrench in there, what if the DTO accountId was not the actual "id" field in the table, but another custom field, I have another situation like that, would it even be possible? I still need the answer the the 1st question however with a standard id.
you may use entityManager.getReference as explained here
reportLine.setAccount(entityManager.getReference(Account.class, line.accountId));
I have two classes Athlete and Injury, the last one contains Athlete object, when the serialization happens I get the following JSON representation back:
{"id":X,"kindOfInjury":"...","muscle":"...","side":"...","outOfTrainig":Y,"injuryDate":"2018-Jun-02","athlete":{"id":X,"firstName":"...","lastName":"...","age":X,"email":"..."}}
I don't want to get all the information about Athlete - just an id value, like "athleteId":1, instead of getting the entire object representation.
So, I have found that I need to apply my custom Serializer which implements StdSerializer on Injury class. So this is what I got so far:
class InjurySerializer extends StdSerializer<Injury> {
public InjurySerializer() {
this(null);
}
public InjurySerializer(Class<Injury> i) {
super(i);
}
#Override
public void serialize(
Injury value, JsonGenerator jgen, SerializerProvider provider)
throws IOException, JsonProcessingException {
jgen.writeStartObject();
jgen.writeNumberField("id", value.getId());
jgen.writeStringField("kindOfInjury", value.getKindOfInjury());
jgen.writeStringField("muscle", value.getMuscle());
jgen.writeStringField("side", value.getSide());
jgen.writeNumberField("outOfTraining", value.getOutOfTraining());
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MMM-dd");
Date date = new Date();
String ourformat = formatter.format(date.getTime());
jgen.writeStringField("injuryDate", ourformat);
jgen.writeNumberField("athleteId", value.getAthlete().getId());
jgen.writeEndObject();
}
}
And the actual Injury class:
#Entity
#Table(name = "INJURY")
#JsonSerialize(using = InjurySerializer.class)
public class Injury {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "INJURY_ID")
private Long id;
#Column(name = "KIND_OF_INJURY")
private String kindOfInjury;
#Column(name = "MUSCLE")
private String muscle;
#Column(name = "SIDE")
private String side;
#Column(name = "OUT_OF_TRAINING")
private Integer outOfTraining;
#JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MMM-dd")
#Column(name = "INJURY_DATE")
private Date injuryDate;
#ManyToOne
#JoinColumn(name = "ATHLETE_ID")
private Athlete athlete;
So, this solution works, but it looks terrible...
Question is the following:
1) Is there any mechanism which provides me functionality to change the serialization of only ONE property which I really need, instead of writing all this tedious code, where the actual change is only in this line? :
jgen.writeNumberField("athleteId", value.getAthlete().getId());
2) Could you recommend me something to read about Jackson because at this point I have a little bit mess in my head about it?
Thanks for the patience and I'm looking forwards for your responses :)
You can use the Data Transfer Object (DTO) for that purposes.
Create a simple POJO like this:
public class InjuryDTO {
//all other required fields from Injury model...
#JsonProperty("athlete_id")
private Long athleteId;
}
And converter for it:
#Component
public class InjuryToDTOConverter{
public InjuryDTO convert(Injury source){
InjuryDTO target = new InjuryDTO();
BeanUtils.copyProperties(source, target); //it will copy fields with the same names
target.setAthleteId(source.getAthlete().getId());
return target;
}
}
You can use it like that:
#RestController("/injuries")
public class InjuryController {
#Autowired
private InjuryToDTOConverter converter;
#Autowired
private InjuryService injuryService;
#GetMapping
public InjuryDTO getInjury(){
Injury injury = injuryService.getInjury();
return converter.convert(injury);
}
}
The benefit of this approach is that you can have multiple DTOs for different purposes.
You might find it less tedious to use the #JsonIgnore annotation instead of writing a custom serializer. Take this example
public class Person {
private int id;
#JsonIgnore
private String first;
#JsonIgnore
private String last;
#JsonIgnore
private int age;
// getters and setters omitted
}
When Jackson serializes this class, it only includes the "id" property in the resulting JSON.
#Test
void serialize_only_includes_id() throws JsonProcessingException {
final var person = new Person();
person.setId(1);
person.setFirst("John");
person.setLast("Smith");
person.setAge(22);
final var mapper = new ObjectMapper();
final var json = mapper.writeValueAsString(person);
assertEquals("{\"id\":1}", json);
}
You can try manupulating json string using basic string replace method.
I ran your json and converted it to your desired format:
public static void main(String args[]) {
String json = "{\"id\":123,\"kindOfInjury\":\"...\",\"muscle\":\"...\",\"side\":\"...\",\"outOfTrainig\":Y,\"injuryDate\":\"2018-Jun-02\",\"athlete\":{\"id\":456,\"firstName\":\"...\",\"lastName\":\"...\",\"age\":14,\"email\":\"...\"}}";
JsonObject injury = new JsonParser().parse(json).getAsJsonObject();
JsonObject athelete = new JsonParser().parse(injury.get("athlete").toString()).getAsJsonObject();
String updateJson = injury.toString().replace(injury.get("athlete").toString(), athelete.get("id").toString());
updateJson = updateJson.replace("athlete", "athleteId");
System.out.println(updateJson);
}
output:
{"id":123,"kindOfInjury":"...","muscle":"...","side":"...","outOfTrainig":"Y","injuryDate":"2018-Jun-02","athleteId":456}
Dependency:
implementation 'com.google.code.gson:gson:2.8.5'
If you can replace with regex that will be bit more cleaner.
I have in my controller:
#RestController
public class OneTwoController {
private OnTwoService _service;
//... more code
#PostMapping("/api/one-two")
#CrossOrigin
public ResponseEntity<ServiceResponse> save(#RequestBody OneTwo model) {
return ResponseEntity.ok().body( _service.Save(model));
}
In my entity:
#Entity(name = "OneTwo")
#Where (clause = "deleted='false'")
public class OneTwo{
#EmbeddedId
private OneTwoKey_id;
public OneTwo(OneTwoKey id) {
this._id = id;
}
#JsonProperty("oneTwo")
public void setId(OneTwoKey value) {
this._id = value;
}
The OneTwoKey class:
public class OneTwoKey implements Serializable {
#Column(name = "OneID")
private int _oneID;
#Column(name = "TwoID")
private int _twoID;
public OneTwoKey(int oneID, int twoID) {
this._oneID = oneID;
this._twoID = twoID;
}
}
The json that I send to the Rest API:
{
"oneTwo": {
"oneID": 83,
"twoID": 69
},
"deleted": true
}
The issue is that both ids arrive null, so the service can't do the insert on the DB.
How can I deal with those cases when the ids are more than one?
Try adding setters in the OneTwoKey class to make it easier for the JSON deserializer:
#JsonProperty("oneID")
public void setOneID(int oneID) {
this._oneID = oneID;
}
#JsonProperty("twoID")
public void setTwoID(int twoID) {
this._twoID = twoID;
}
Another solution is to create a DTO, use it to receive the data in the controller and then convert it to your entity:
public class OneTwoDTO {
private Map<String, Int> oneTwo;
private boolean deleted;
// setters & getters
}
Simply what you can do is instead of using
public ResponseEntity<ServiceResponse> save(#RequestBody OneTwo model) {
you can use
public ResponseEntity<ServiceResponse> save(#RequestBody String model) {
Now convert the String to json and get all the key value pairs, it would be easier if you have dynamic number of variables and you want to capture them all.
or you can use tools like jsonschema2pojo whick take a json schema and generate a pojo. In the json schema if you set
"additionalProperties": true
you can capture all the values.
Could you make sure the problem is not because of case sensitivity?
Lower case the column names. Also could you use public access on those variables as well? These are my initial guesses as to why the payload is not being binded correctly.
public class OneTwoKey implements Serializable {
#Column(name = "oneID")
public int _oneID;
#Column(name = "twoID")
public int _twoID;
I have these two classes:
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id",scope = Rol.class)
public class Rol extends MyEntity implements Serializable {
private Integer id;
private String rolName;
public Rol(Integer id, String rolName) {
this.id = id;
this.rolName = rolName;
}
...
}
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id",scope = User.class)
public class User extends MyEntity implements Serializable {
private Integer id;
private String name;
private List<Rol> rolList;
public User(Integer id, String name, List<Rol> rolList) {
this.id = id;
this.name = name;
this.rolList = rolList;
}
...
}
and I try to serialize and deserialize the user object as following
Rol rol1 = new Rol(1, "MyRol");
Rol rol2 = new Rol(1, "MyRol");
List<Rol> rolList = new ArrayList();
rolList.add(rol1);
rolList.add(rol2);
user = new User(1, "MyUser", rolList);
ObjectMapper mapper = new ObjectMapper();
String jsonString = mapper.writeValueAsString(user);
User userJson = mappe.readValue(jsonString, User.class);
and the JsonMappingException: Already had POJO for id is produced. Why?
When I review the json result of the serialization I see that the result is
{"id": 1,"name": "MyName","rolList": [{"id": 1,"rolName": "MyRol"},{"id": 1,"rolName": "MyRol"}]}
when the result should be
{"id": 1,"name": "MyName","rolList": [{"id": 1,"rolName": "MyRol"},1]}
because rol1 and rol2 are different instances of the same POJO identifier with id 1.
How can I avoid the JsonMappingException? In my project I have some different instances of the same POJO. I can guarantee that if the id's are equal -> objects are equal.
Excuse me for my bad English.
For anyone returning to this question, it looks like there's option to do this with a custom ObjectIdResolver in Jackson. You can specify this on the #JsonIdentityInfo annotation, e.g. :
#JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "name",
resolver = CustomObjectIdResolver.class)
Then perhaps wrap the normal SimpleObjectIdResolver class to get going and customise bindItem().
In my case I wanted to avoid overlapping objectIds, so cleared down the references when I started a new Something:
public class CustomObjectIdResolver implements ObjectIdResolver {
private ObjectIdResolver objectIdResolver;
public CustomObjectIdResolver() {
clearReferences();
}
#Override
public void bindItem(IdKey id, Object pojo) {
// Time to drop the references?
if (pojo instanceof Something)
clearReferences();
objectIdResolver.bindItem(id, pojo);
}
#Override
public Object resolveId(IdKey id) {
return objectIdResolver.resolveId(id);
}
#Override
public boolean canUseFor(ObjectIdResolver resolverType) {
return resolverType.getClass() == getClass();
}
#Override
public ObjectIdResolver newForDeserialization(Object context) {
return new CustomObjectIdResolver();
}
private void clearReferences() {
objectIdResolver = new SimpleObjectIdResolver();
}
}
Jackson expects in this case different id for different class instances. There has been a previous discussion at github here. Overriding hashCode and equals will not help. Object references must match for equal id.
Options
Reuse Rol instances instead of making new ones with equal fields. As a bonus you will also save memory.
Modify the application logic so that it doesn't depend on #JsonIdentityInfo