This might be a duplicate. But I cannot find a solution to my Problem.
I have a class
public class MyResponse implements Serializable {
private boolean isSuccess;
public boolean isSuccess() {
return isSuccess;
}
public void setSuccess(boolean isSuccess) {
this.isSuccess = isSuccess;
}
}
Getters and setters are generated by Eclipse.
In another class, I set the value to true, and write it as a JSON string.
System.out.println(new ObjectMapper().writeValueAsString(myResponse));
In JSON, the key is coming as {"success": true}.
I want the key as isSuccess itself. Is Jackson using the setter method while serializing? How do I make the key the field name itself?
This is a slightly late answer, but may be useful for anyone else coming to this page.
A simple solution to changing the name that Jackson will use for when serializing to JSON is to use the #JsonProperty annotation, so your example would become:
public class MyResponse implements Serializable {
private boolean isSuccess;
#JsonProperty(value="isSuccess")
public boolean isSuccess() {
return isSuccess;
}
public void setSuccess(boolean isSuccess) {
this.isSuccess = isSuccess;
}
}
This would then be serialised to JSON as {"isSuccess":true}, but has the advantage of not having to modify your getter method name.
Note that in this case you could also write the annotation as #JsonProperty("isSuccess") as it only has the single value element
I recently ran into this issue and this is what I found. Jackson will inspect any class that you pass to it for getters and setters, and use those methods for serialization and deserialization. What follows "get", "is" and "set" in those methods will be used as the key for the JSON field ("isValid" for getIsValid and setIsValid).
public class JacksonExample {
private boolean isValid = false;
public boolean getIsValid() {
return isValid;
}
public void setIsValid(boolean isValid) {
this.isValid = isValid;
}
}
Similarly "isSuccess" will become "success", unless renamed to "isIsSuccess" or "getIsSuccess"
Read more here: http://www.citrine.io/blog/2015/5/20/jackson-json-processor
Using both annotations below, forces the output JSON to include is_xxx:
#get:JsonProperty("is_something")
#param:JsonProperty("is_something")
When you are using Kotlin and data classes:
data class Dto(
#get:JsonProperty("isSuccess") val isSuccess: Boolean
)
You might need to add #param:JsonProperty("isSuccess") if you are going to deserialize JSON as well.
EDIT: If you are using swagger-annotations to generate documentation, the property will be marked as readOnly when using #get:JsonProperty. In order to solve this, you can do:
#JsonAutoDetect(isGetterVisibility = JsonAutoDetect.Visibility.NONE)
data class Dto(
#field:JsonProperty(value = "isSuccess") val isSuccess: Boolean
)
You can configure your ObjectMapper as follows:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if(method.hasReturnType() && (method.getRawReturnType() == Boolean.class || method.getRawReturnType() == boolean.class)
&& method.getName().startsWith("is")) {
return method.getName();
}
return super.nameForGetterMethod(config, method, defaultName);
}
});
I didn't want to mess with some custom naming strategies, nor re-creating some accessors.
The less code, the happier I am.
This did the trick for us :
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
#JsonIgnoreProperties({"success", "deleted"}) // <- Prevents serialization duplicates
public class MyResponse {
private String id;
private #JsonProperty("isSuccess") boolean isSuccess; // <- Forces field name
private #JsonProperty("isDeleted") boolean isDeleted;
}
Building upon Utkarsh's answer..
Getter names minus get/is is used as the JSON name.
public class Example{
private String radcliffe;
public getHarryPotter(){
return radcliffe;
}
}
is stored as { "harryPotter" : "whateverYouGaveHere" }
For Deserialization, Jackson checks against both the setter and the field name.
For the Json String { "word1" : "example" }, both the below are valid.
public class Example{
private String word1;
public setword2( String pqr){
this.word1 = pqr;
}
}
public class Example2{
private String word2;
public setWord1(String pqr){
this.word2 = pqr ;
}
}
A more interesting question is which order Jackson considers for deserialization. If i try to deserialize { "word1" : "myName" } with
public class Example3{
private String word1;
private String word2;
public setWord1( String parameter){
this.word2 = parameter ;
}
}
I did not test the above case, but it would be interesting to see the values of word1 & word2 ...
Note: I used drastically different names to emphasize which fields are required to be same.
You can change primitive boolean to java.lang.Boolean (+ use #JsonPropery)
#JsonProperty("isA")
private Boolean isA = false;
public Boolean getA() {
return this.isA;
}
public void setA(Boolean a) {
this.isA = a;
}
Worked excellent for me.
If you are interested in handling 3rd party classes not under your control (like #edmundpie mentioned in a comment) then you add Mixin classes to your ObjectMapper where the property/field names should match the ones from your 3rd party class:
public class MyStack32270422 {
public static void main(String[] args) {
ObjectMapper om3rdParty = new ObjectMapper();
om3rdParty .addMixIn(My3rdPartyResponse.class, MixinMyResponse.class);
// add further mixins if required
String jsonString = om3rdParty.writeValueAsString(new My3rdPartyResponse());
System.out.println(jsonString);
}
}
class MixinMyResponse {
// add all jackson annotations here you want to be used when handling My3rdPartyResponse classes
#JsonProperty("isSuccess")
private boolean isSuccess;
}
class My3rdPartyResponse{
private boolean isSuccess = true;
// getter and setter here if desired
}
Basically you add all your Jackson annotations to your Mixin classes as if you would own the class. In my opinion quite a nice solution as you don't have to mess around with checking method names starting with "is.." and so on.
there is another method for this problem.
just define a new sub-class extends PropertyNamingStrategy and pass it to ObjectMapper instance.
here is a code snippet may be help more:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) {
String input = defaultName;
if(method.getName().startsWith("is")){
input = method.getName();
}
//copy from LowerCaseWithUnderscoresStrategy
if (input == null) return input; // garbage in, garbage out
int length = input.length();
StringBuilder result = new StringBuilder(length * 2);
int resultLength = 0;
boolean wasPrevTranslated = false;
for (int i = 0; i < length; i++)
{
char c = input.charAt(i);
if (i > 0 || c != '_') // skip first starting underscore
{
if (Character.isUpperCase(c))
{
if (!wasPrevTranslated && resultLength > 0 && result.charAt(resultLength - 1) != '_')
{
result.append('_');
resultLength++;
}
c = Character.toLowerCase(c);
wasPrevTranslated = true;
}
else
{
wasPrevTranslated = false;
}
result.append(c);
resultLength++;
}
}
return resultLength > 0 ? result.toString() : input;
}
});
The accepted answer won't work for my case.
In my case, the class is not owned by me. The problematic class comes from 3rd party dependencies, so I can't just add #JsonProperty annotation in it.
To solve it, inspired by #burak answer above, I created a custom PropertyNamingStrategy as follow:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForSetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if (method.getParameterCount() == 1 &&
(method.getRawParameterType(0) == Boolean.class || method.getRawParameterType(0) == boolean.class) &&
method.getName().startsWith("set")) {
Class<?> containingClass = method.getDeclaringClass();
String potentialFieldName = "is" + method.getName().substring(3);
try {
containingClass.getDeclaredField(potentialFieldName);
return potentialFieldName;
} catch (NoSuchFieldException e) {
// do nothing and fall through
}
}
return super.nameForSetterMethod(config, method, defaultName);
}
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if(method.hasReturnType() && (method.getRawReturnType() == Boolean.class || method.getRawReturnType() == boolean.class)
&& method.getName().startsWith("is")) {
Class<?> containingClass = method.getDeclaringClass();
String potentialFieldName = method.getName();
try {
containingClass.getDeclaredField(potentialFieldName);
return potentialFieldName;
} catch (NoSuchFieldException e) {
// do nothing and fall through
}
}
return super.nameForGetterMethod(config, method, defaultName);
}
});
Basically what this does is, before serializing and deserializing, it checks in the target/source class which property name is present in the class, whether it is isEnabled or enabled property.
Based on that, the mapper will serialize and deserialize to the property name that is exist.
I have made a small class, which inherits from DataGrid and takes in classes that derive from a specific interface:
public class RecordDataGrid<T> : DataGrid where T : IRecord
{
public RecordDataGrid()
{
this.AutoGenerateColumns = false;
this.CanUserAddRows = false;
this.CanUserDeleteRows = false;
this.CanUserResizeRows = false;
this.IsReadOnly = true;
this.SelectionMode = DataGridSelectionMode.Single;
this.Margin = new System.Windows.Thickness(0, 10, 0, 0);
var propertyInfos = typeof(T).GetProperties();
var list = new Dictionary<PropertyInfo, DataGridColumnAttribute>();
foreach (var propertyInfo in propertyInfos)
{
var customAttributes = propertyInfo.GetCustomAttributes(true);
foreach (var customAttr in customAttributes)
{
if (customAttr != null && customAttr is DataGridColumnAttribute)
{
list.Add(propertyInfo, (DataGridColumnAttribute)customAttr);
}
}
}
var ordered = (from entry in list orderby entry.Value.OrderIndex ascending select entry).ToDictionary(e => e.Key, e => e.Value);
foreach (var kvp in ordered)
{
var propertyInfo = kvp.Key;
var dgcAttr = kvp.Value;
var column = new DataGridTextColumn();
column.Header = dgcAttr.DisplayName;
column.Binding = new Binding(propertyInfo.Name);
column.Binding.StringFormat = dgcAttr.StringFormat ?? null;
column.Width = dgcAttr.ColumnWidthType == DataGridColumnAttribute.ColumnWidthTypes.Auto ? new DataGridLength(10, DataGridLengthUnitType.Auto) : new DataGridLength(10, DataGridLengthUnitType.Star);
this.Columns.Add(column);
}
}
}
It is very rough at the moment, just testing a few things out. The goal is to make my life easier by letting the DataGrid fill the Columns by itself, based on a custom Attribute:
public class DataGridColumnAttribute : Attribute
{
public string DisplayName { get; private set; }
public string StringFormat { get; private set; }
public ColumnWidthTypes ColumnWidthType { get; private set; }
public int OrderIndex { get; private set; }
public DataGridColumnAttribute(string displayName, int orderIndex, string stringFormat = null, ColumnWidthTypes columnWidthType = ColumnWidthTypes.Auto)
{
DisplayName = displayName;
StringFormat = stringFormat;
OrderIndex = OrderIndex;
ColumnWidthType = columnWidthType;
}
public enum ColumnWidthTypes
{
Auto,
Fill
}
}
Later on, as far as I am concerned, I should be able to use it in xaml like this:
Namespaces:
xmlns:model="clr-namespace:NickX.KswErp.Model.Classes;assembly=NickX.KswErp.Model"
xmlns:ctrl="clr-namespace:NickX.KswErp.ClientApplication.UI.Controls"
Control:
<ctrl:RecordDataGrid x:Name="_gridTransactions" x:TypeArguments="model:TransactionRecord" />
But I get following compilation error:
Only a master tag can specify the "x: TypeArguments" attribute.
(Roughly translated by google translation)
Maybe my approach is completely wrong tho. Should I do it completle in code behind. Or are there better approaches? Please let me know!
Conveniently I just found a thread in a german forum, which answeres my exact question. So people questioning the same in the future:
It is not possible. Easiest thing to do at this point is making a specific class for each model, which again derives from your generic class.
In my case:
public class TransactionDataGrid : RecordDataGrid<TransactionRecord>
{
}
Doesen't seem like a nice solution to me, and probably isn't the best way to do it. But it works.
finally after extensive stack-overflowing ;-) and debugging I made it work:
My Feign-client can make requests on Spring-Data-Rest's API and I get a Resource<Something> with filled links back.
My code so far...
The FeignClient:
#FeignClient(name = "serviceclient-hateoas",
url = "${service.url}",
decode404 = true,
path = "${service.basepath:/api/v1}",
configuration = MyFeignHateoasClientConfig.class)
public interface MyFeignHateoasClient {
#RequestMapping(method = RequestMethod.GET, path = "/bookings/search/findByBookingUuid?bookingUuid={uuid}")
Resource<Booking> getBookingByUuid(#PathVariable("uuid") String uuid);
}
The client-config:
#Configuration
public class MyFeignHateoasClientConfig{
#Value("${service.user.name:bla}")
private String serviceUser;
#Value("${service.user.password:blub}")
private String servicePassword;
#Bean
public BasicAuthRequestInterceptor basicAuth() {
return new BasicAuthRequestInterceptor(serviceUser, servicePassword);
}
#Bean
public Decoder decoder() {
return new JacksonDecoder(getObjectMapper());
}
#Bean
public Encoder encoder() {
return new JacksonEncoder(getObjectMapper());
}
public ObjectMapper getObjectMapper() {
return new ObjectMapper()
.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
.registerModule(new Jackson2HalModule());
}
#Bean
public Logger logger() {
return new Slf4jLogger(MyFeignHateoasClient.class);
}
#Bean
public Logger.Level logLevel() {
return Logger.Level.FULL;
}
}
And in the application using the client via an jar-dependency:
#SpringBootApplication
#EnableAutoConfiguration
#EnableFeignClients(basePackageClasses=MyFeignHateoasClient.class)
#EnableHypermediaSupport(type = EnableHypermediaSupport.HypermediaType.HAL)
#ComponentScan(excludeFilters = #Filter(type = ... ), basePackageClasses= {....class}, basePackages="...")
public class Application {
...
Now this is working:
#Autowired
private MyFeignHateoasClient serviceClient;
...
void test() {
Resource<Booking> booking = serviceClient.getBookingByUuid(id);
Link link = booking.getLink("relation-name");
}
Now my question:
How do I go on from here, i.e. navigate to the resource in the Link?
The Link is containing an URL on the resource I want to request.
Do I really have to parse the ID out of the URL and add a method to the FeignClient like getRelationById(id)
Is there at least a way to pass the complete resource-url to a method of a FeignClient?
I have found no examples which demonstrate how to proceed from here (despite the POST/modify). Any hints appreciated!
Thx
My current solution:
I added an additional request in the Feign client, taking the whole resource path:
...
public interface MyFeignHateoasClient {
...
#RequestMapping(method = RequestMethod.GET, path = "{resource}")
Resource<MyLinkedEntity> getMyEntityByResource(#PathVariable("resource") String resource);
}
Then I implemented some kind of "HAL-Tool":
...
import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
import org.springframework.hateoas.Link;
import feign.Target;
import lombok.SneakyThrows;
public class HalTool {
private Object feignClient;
public static HalTool forClient( Object feignClient ) {
return new HalTool(feignClient);
}
private HalTool( Object feignClient ) {
this.feignClient = feignClient;
}
#SneakyThrows
private String getUrl() {
InvocationHandler invocationHandler = Proxy.getInvocationHandler(feignClient);
Field target = invocationHandler.getClass().getDeclaredField("target");
target.setAccessible(true);
Target<?> value = (Target<?>) target.get(invocationHandler);
return value.url();
}
public String toPath( Link link ) {
String href = link.getHref();
String url = getUrl();
int idx = href.indexOf(url);
if (idx >= 0 ) {
idx += url.length();
}
return href.substring(idx);
}
}
And then I could do request a linked resource like this:
Link link = booking.getLink("relation-name");
Resource<MyLinkedEntity> entity = serviceClient.getMyEntityByResource(
HalTool.forClient(serviceClient).toPath(link));
I try to use foreign collections in ORMLite. However, I dont know how to convert it into list. I try to do something like this :
public class Car implements Serializable {
#DatabaseField(columnName = "carId" , generatedId = true, id=true)
private int id;
#DatabaseField(columnName = "carNumber")
private String mNumber;
#DatabaseField(columnName = "carName")
private String mName;
#ForeignCollectionField(eager = true,columnName = "carParts")
private Collection<Part> mParts;
ArrayList<Part> parts = new ArrayList<>(mParts);
public ArrayList<Part> getParts() {
return parts;
}
public void setParts(ArrayList<Part> parts) {
this.parts = parts;
}
but when I try to use it I get exception :
java.lang.NullPointerException: collection == null
at this line :
ArrayList<Part> parts = new ArrayList<>(mParts);
please, help.
The reason is simple - you have to wait until mParts will be initialized by ORMLite library, then you can create ArrayList from it.
public ArrayList<Part> getParts() {
return new ArrayList<>( mParts );
}
i have two Presenters: A DevicePresenter and a ContainerPresenter. I place a PlaceRequest in the DevicePresenter to call the ContainerPresenter with some parameters like this:
PlaceRequest request = new PlaceRequest.Builder()
.nameToken("containersPage")
.with("action","editContainer")
.with("containerEditId", selectedContainerDto.getUuid().toString())
.build();
placeManager.revealPlace(request);
In my ContainersPresenter i have this overridden method:
#Override
public void prepareFromRequest(PlaceRequest placeRequest) {
Log.debug("prepareFromRequest in ContainersPresenter");
super.prepareFromRequest(placeRequest);
String actionString = placeRequest.getParameter("action", "");
String id;
//TODO: Should we change that to really retrieve the object from the server? Or should we introduce a model that keeps all values and inject that into all presenters?
if (actionString.equals("editContainer")) {
try {
id = placeRequest.getParameter("id", null);
for(ContainerDto cont : containerList) {
Log.debug("Compare " + id + " with " + cont.getUuid());
if(id.equals(cont.getUuid())) {
containerDialog.setCurrentContainerDTO(new ContainerDto());
addToPopupSlot(containerDialog);
break;
}
}
} catch (NumberFormatException e) {
Log.debug("id cannot be retrieved from URL");
}
}
}
But when revealPlace is called, the URL in the browser stays the same and the default presenter (Home) is shown instead.
When i print the request, it seems to be fine:
PlaceRequest(nameToken=containersPage, params={action=editContainer, containerEditId=8fa5f730-fe0f-11e3-a3ac-0800200c9a66})
And my NameTokens are like this:
public class NameTokens {
public static final String homePage = "!homePage";
public static final String containersPage = "!containersPage";
public static final String devicesPage = "!devicesPage";
public static String getHomePage() {
return homePage;
}
public static String getDevicesPage() {
return devicesPage;
}
public static String getContainersPage() {
return containersPage;
}
}
What did i miss? Thanks!
In your original code, when constructing your PlaceRequest, you forgot the '!' at the beginning of your nametoken.
.nameToken("containersPage")
while your NameTokens entry is
public static final String containersPage = "!containersPage";
As you noted, referencing the constant in NameTokens is less prone to such easy mistakes to make!
Sometimes the problem exists "between the ears". If i avoid strings but use the proper symbol from NameTokens like
PlaceRequest request = new PlaceRequest.Builder()
.nameToken(NameTokens.containersPage)
.with("action","editContainer")
.with("containerEditId", selectedContainerDto.getUuid().toString())
.build();
it works just fine. Sorry!