I'm trying to force gson to throw an exception when an string does not map to an object which I'm passing to it.
#ResponseStatus(HttpStatus.CREATED)
#PostMapping("offer")
public String postOffer(#RequestBody String jsonBody) {
Offer offer = gson.fromJson(jsonBody, Offer.class);
offerRepository.save(offer);
return offer.getId();
}
Currently, it will just save what ever it can to the db and ignore any elements that don't map to the class. This is bad for me because I get bad data making it's way to the db.
Any help would be appreciated.
ps. using springboot-data-mongodb and gson for mapping.
Thanks
In GSON you cannot make some fields required.
You can handle this i your code, if the variable is not present in json then in Offer object that variable will simple be assigned as null.
You can add null check to your code for the required fields and throw your own exception.
Since gson dont have this facility, you can also try the answer from below link-
Gson optional and required fields
To achieve this you need to follow two steps:-
1) Mark all required field in Offer class as #NotNull(message="your custom message")
2) Add below class to tell Mongo to validate document before persisting it to the database.
#Configuration
public class MongoEventValidationListener {
#Bean
public ValidatingMongoEventListener validatingMongoEventListener() {
return new ValidatingMongoEventListener(validator());
}
#Bean
public LocalValidatorFactoryBean validator() {
return new LocalValidatorFactoryBean();
}
}
Related
This seems to be a missing part in the documentation of Vaadin...
I call an API to get data in my UI like this:
#Override
public URI getUri(String url, PageRequest page) {
return UriComponentsBuilder.fromUriString(url)
.queryParam("page", page.getPageNumber())
.queryParam("size", page.getPageSize())
.queryParam("sort", (page.getSort().isSorted() ? page.getSort() : ""))
.build()
.toUri();
}
#Override
public Mono<Page<SomeDto>> getDataByPage(PageRequest pageRequest) {
return webClient.get()
.uri(getUri(URL_API + "/page", pageRequest))
.retrieve()
.bodyToMono(new ParameterizedTypeReference<>() {
});
}
In the Vaadin documentation (https://vaadin.com/docs/v10/flow/binding-data/tutorial-flow-data-provider), I found an example with DataProvider.fromCallbacks but this expects streams and that doesn't feel like the correct approach as I need to block on the requests to get the streams...
DataProvider<SomeDto, Void> lazyProvider = DataProvider.fromCallbacks(
q -> service.getData(PageRequest.of(q.getOffset(), q.getLimit())).block().stream(),
q -> service.getDataCount().block().intValue()
);
When trying this implementation, I get the following error:
org.springframework.core.codec.CodecException: Type definition error: [simple type, class org.springframework.data.domain.Page]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `org.springframework.data.domain.Page` (no Creators, like default constructor, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
at [Source: (io.netty.buffer.ByteBufInputStream); line: 1, column: 1]
grid.setItems(lazyProvider);
I don't have experience with vaadin, so i'll talk about the deserialization problem.
Jackson needs a Creator when deserializing. That's either:
the default no-arg constructor
another constructor annotated with #JsonCreator
static factory method annotated with #JsonCreator
If we take a look at spring's implementations of Page - PageImpl and GeoPage, they have neither of those. So you have two options:
Write your custom deserializer and register it with the ObjectMapper instance
The deserializer:
public class PageDeserializer<T> extends StdDeserializer<Page<T>> {
public PageDeserializer() {
super(Page.class);
}
#Override
public Page<T> deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JacksonException {
//TODO implement for your case
return null;
}
}
And registration:
SimpleModule module = new SimpleModule();
module.addDeserializer(Page.class, new PageDeserializer<>());
objectMapper.registerModule(module);
Make your own classes extending PageImpl, PageRequest, etc. and annotate their constructors with #JsonCreator and arguments with #JsonProperty.
Your page:
public class MyPage<T> extends PageImpl<T> {
#JsonCreator
public MyPage(#JsonProperty("content_prop_from_json") List<T> content, #JsonProperty("pageable_obj_from_json") MyPageable pageable, #JsonProperty("total_from_json") long total) {
super(content, pageable, total);
}
}
Your pageable:
public class MyPageable extends PageRequest {
#JsonCreator
public MyPageable(#JsonProperty("page_from_json") int page, #JsonProperty("size_from_json") int size, #JsonProperty("sort_object_from_json") Sort sort) {
super(page, size, sort);
}
}
Depending on your needs for Sort object, you might need to create MySort as well, or you can remove it from constructor and supply unsorted sort, for example, to the super constructor. If you are deserializing from input manually you need to provide type parameters like this:
JavaType javaType = TypeFactory.defaultInstance().constructParametricType(MyPage.class, MyModel.class);
Page<MyModel> deserialized = objectMapper.readValue(pageString, javaType);
If the input is from request body, for example, just declaring the generic type in the variable is enough for object mapper to pick it up.
#PostMapping("/deserialize")
public ResponseEntity<String> deserialize(#RequestBody MyPage<MyModel> page) {
return ResponseEntity.ok("OK");
}
Personally i would go for the second option, even though you have to create more classes, it spares the tediousness of extracting properties and creating instances manually when writing deserializers.
There are two parts to this question.
The first one is about asynchronously loading data for a DataProvider in Vaadin. This isn't supported since Vaadin has prioritized the typical case with fetching data straight through JDBC. This means that you end up blocking a thread while the data is loading. Vaadin 23 will add support for doing that blocking on a separate thread instead of keeping the UI thread blocked, but it will still be blocking.
The other half of your problem doesn't seem to be directly related to Vaadin. The exception message says that the Jackson instance used by the REST client isn't configured to support creating instances of org.springframework.data.domain.Page. I don't have direct experience with this part of the problem, so I cannot give any advice on exactly how to fix it.
Basically, I'm trying to validate inputs from the #RequestBody of a REST controller using an #ExceptionHandler to catch MethodArgumentNotValidException constraints.
#PostMapping(value = "/createbaseline")
public ResponseEntity<?> createBaseline(#Valid #RequestPart Baseline baseline){
//...
return ResponseEntity.ok("...");
}
Before I can do that Jackson is throwing an InvalidFormatException when it fails to parse a string to a Date, thus preventing my #ExceptionHandler from validating the remaining inputs. Here is my #ExceptionHandler method that I want to use for validating inputs.
#ExceptionHandler(MethodArgumentNotValidException.class)
protected final ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex){
Map<String, String> errors = new HashMap<>();
ex.getBindingResult().getAllErrors().forEach(error -> {
String[] mapping = error.getDefaultMessage().split(":");
errors.put(mapping[0], mapping[1]);
});
return new ResponseEntity<>(errors, HttpStatus.BAD_REQUEST);
}
I've considered just changing the Date property of the object to a String, but I know that's against best practices. The reason why I want to use the handleMethodArgumentNotValid is because I have custom constraint annotations on fields in my objects that specify a key that I can access via MethodArgumentNotValidException.getBindingResult() like so:
#RequiredFieldConstraint(key = "label")
private String label;
The client can then use those keys to determine which input field will show an error. If I used the method below to catch the InvalidFormatException then I don't have access to those keys specified by the field annotations.
#ExceptionHandler(value = {InvalidFormatException.class})
protected ResponseEntity<Object> handleException(Exception e){
//can't access annotation keys in this method body
return ResponseEntity.badRequest().body("bad");
}
I need to be able to validate ALL inputs sent in the #ResponseBody in order to send the appropriate error message back to the client but I'd still like to utilize deserializing the #RequestBody directly into an object. Does anyone have ideas on how to approach or work around this?
I found a work around for this by implementing a custom deserializer for Dates so that it catches the InvalidFormatException but still returns a new Date() with .setTime(-1) that I can check for in my handleMethodArgumentNotValid method along with all the other inputs.
I've seen examples on SO of excluding fields from serialization at runtime. I need to do that, but I'd like to have Gson handle serialization of all the fields not being excluded.
The complicating part is that I can't have Gson do the serialization first, then have a TypeAdapter modify the result. I need to somehow do the exclusion first, then have what remains be serialized. Is this even possible?
Ok, with some experimentation, and this helpful post, I was able to cobble together a way to conditionally exclude mocked fields.
The reason I'm going to all this trouble is that out-of-the-box Gson throws an exception when it encounters Spock-mocked fields.
For Spock, my check to determine if a field is mocked is to see if the class name of the value it references contains the substring EnhancerByCGLib.
Below, ResizingArrayQueueOfStrings.arrayFactory is the field that may, or may not, be mocked.
Thankfully, I can use a single JsonSerializer for all classes that need this sort of treatment. Ideally, I wouldn't have to register the serializer for every class that might be mocked... but that's a battle for another day.
The resulting JSON, when the field is mocked and ResizingArrayQueueOfStrings is serialized, is
queue {
"arrayFactory": "** mocked **",
}
otherwise, it's
queue {
"arrayFactory": {},
}
Hope this helps others with a similar need.
public class MockSerializer implements JsonSerializer<Object> {
#Override
public JsonElement serialize(Object src, Type typeOfSrc, JsonSerializationContext context) {
Gson gson = new Gson();
String className = src.getClass().getName();
boolean isMocked = className.contains("EnhancerByCGLIB");
if (isMocked) return new JsonPrimitive("** mocked **");
else return gson.toJsonTree(src);
}
}
public class ResizingArrayQueueOfStrings {
private ArrayFactory arrayFactory;
public String toString() {
Gson gson = new GsonBuilder()
.registerTypeAdapter(ArrayFactory.class, new MockSerializer())
.setPrettyPrinting()
.create();
return gson.toJson(this);
}
}
what is best way to add member in group using spring LdapTemplate.
I have successfully create user and remove user ex.
But I'm trying to add member then I'm facing issue.
Add Member Code:
public boolean addMemberToGroup(List<String> groupList, User user) {
boolean isAddedSuccessfully=false;
try{
for(int i=0;i<groupList.size();i++){
Name groupDn = buildGroupDn(groupList.get(i));
DirContextOperations ctx = ldapTemplate.lookupContext(groupDn);
ctx.addAttributeValue("member",buildPersonDn(user.getUid()));
ldapTemplate.update(ctx);
}
isAddedSuccessfully=true;
}
catch(Exception e){
isAddedSuccessfully=false;
}
return isAddedSuccessfully;
}
private Name buildGroupDn(String groupName) {
return LdapNameBuilder.newInstance("cn=groups").add("cn", groupName).build();
}
private Name buildPersonDn(String userID) {
return LdapNameBuilder.newInstance()
.add("uid", userID).add("cn", "users")
.build();
}
Exception Of addMemberToGroup: Class class org.springframework.ldap.core.DirContextAdapter must have a class level interface org.springframework.ldap.odm.annotations.Entry annotation.
please let me know what i am missing.
The updatemethod is intended for use with ODM annotated classes. When working with DirContextAdapter you should use the modifyAttributes method.
Though this is an old question, it's one I had too recently. For anyone coming here in the future, this question is similar to the one found at Spring Malformed 'member' attribute value. Putting together info from both questions, I found the solution to my problem, and share here what worked for me.
In addition to using the modifyAttributes method of the LdapTemplate class, it's also important to pass a String object as the second parameter of the addAttributeValue method of the DirContextOperations class when adding a member, rather than passing a Name object. The toString method called on the corresponding Name object does the trick.
Original code:
DirContextOperations ctx = ldapTemplate.lookupContext(groupDn);
ctx.addAttributeValue("member",buildPersonDn(user.getUid()));
ldapTemplate.update(ctx);
Try this instead:
DirContextOperations ctx = ldapTemplate.lookupContext(groupDn);
ctx.addAttributeValue("member",buildPersonDn(user.getUid()).toString());
ldapTemplate.modifyAttributes(ctx);
I am trying to submit a form from Ext JS 4 to a Spring 3 Controller using JSON. I am using Jackson 1.9.8 for the serialization/deserialization using Spring's built-in Jackson JSON support.
I have a status field that is initially null in the Domain object for a new record. When the form is submitted it generates the following json (scaled down to a few fields)
{"id":0,"name":"someName","status":""}
After submitted the following is seen in the server log
"nested exception is org.codehaus.jackson.map.JsonMappingException: Can not construct instance of com.blah.domain.StatusEnum from String value '': value not one of the declared Enum instance names"
So it appears that Jackson is expecting a valid Enum value or no value at all including an empty string. How do I fix this whether it is in Ext JS, Jackson or Spring?
I tried to create my own ObjectMapper such as
public class MyObjectMapper extends Object Mapper {
public MyObjectMapper() {
configure(DeserializationConfig.Feature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
}
}
and send this as a property to MappingJacksonMappingView but this didn't work. I also tried sending it in to MappingJacksonHttpMessageConverter but that didn't work. Side question: Which one should I be sending in my own ObjectMapper?
Suggestions?
The other thing you could do is create a specialized deserializer (extends org.codehaus.jackson.map.JsonDeserializer) for your particular enum, that has default values for things that don't match. What I've done is to create an abstract deserializer for enums that takes the class it deserializes, and it speeds this process along when I run into the issue.
public abstract class EnumDeserializer<T extends Enum<T>> extends JsonDeserializer<T> {
private Class<T> enumClass;
public EnumDeserializer(final Class<T> iEnumClass) {
super();
enumClass = iEnumClass;
}
#Override
public T deserialize(final JsonParser jp,
final DeserializationContext ctxt) throws IOException, JsonProcessingException {
final String value = jp.getText();
for (final T enumValue : enumClass.getEnumConstants()) {
if (enumValue.name().equals(value)) {
return enumValue;
}
}
return null;
}
}
That's the generic class, basically just takes an enum class, iterates over the values of the enum and checks the next token to match any name. If they do it returns it otherwise return null;
Then If you have an enum MyEnum you'd make a subclass of EnumDeserializer like this:
public class MyEnumDeserializer extends EnumDeserializer<MyEnum> {
public MyEnumDeserializer() {
super(MyEnum.class);
}
}
Then wherever you declare MyEnum:
#JsonDeserialize(using = MyEnumDeserializer.class)
public enum MyEnum {
...
}
I'm not familiar with Spring, but just in case, it may be easier to handle that on the client side:
Ext.define('My.form.Field', {
extend: 'Ext.form.field.Text',
getSubmitValue: function() {
var me = this,
value;
value = me.getRawValue();
if ( value === '' ) {
return ...;
}
}
});
You can also disallow submitting empty fields by setting their allowBlank property to false.
Ended up adding defaults in the EXT JS Model so there is always a value. Was hoping that I didn't have to this but it's not that big of a deal.
I have the same issue. I am reading a JSON stream with some empty strings. I am not in control of the JSON stream, because it is from a foreign service. And I am always getting the same error message. I tried this here:
mapper.getDeserializationConfig().with(DeserializationConfig.Feature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
But without any effect. Looks like a Bug.