I am working on a Spring Boot application. In the html view, I make a ajax call to a RestController, which returns a list of custom entities:
#Controller
public class MyController {
#ResponseBody
#JsonView(View.MyView.class)
public List<CustomEntity> getEntities() {
...
}
}
This is working fine, I am getting, as expected, following structure:
{
"id": "1",
"name": "Test1"
},
{
"id": "2",
"name": "Test2"
}
In the view, I want to use it with Dynatable. And here comes my problem. I need following structure:
{
"records": [
{
"id": "1",
"name": "Test1"
},
{
"id": "2",
"name": "Test2"
}
],
"queryRecordCount": 2,
"totalRecordCount": 2
}
Is there a way to generate the JSOn view using jackson (or any other framework) based on a template, so I can use the data with Dynatable, and if so, how?
Thanks in advance,
Stephan
You could create a wrapper that does this for you...
class DyntableResponse<T> {
private List<T> records;
public List<T> getRecords() { return records; }
public void setRecords(final List<T> records) { this.records = records; }
public int getQueryRecordCount() { return records.size(); }
public int getTotalRecordCount() { return records.size(); }
}
And then return it from your RestController...
#Controller
public class MyController {
#ResponseBody
#JsonView(View.MyView.class)
public DyntableResponse<CustomEntity> getEntities() {
final DyntableResponse<CustomEntity> resp = new DyntableResponse<>();
resp.setRecords(...); // Your finder here.
return resp;
}
}
This is untried, but should be close.
Related
I have a REST API developed with Spring Reactive as below and when it returns the response it does have scanAvailable and prefetch instead of object details. We have individually APIs for the used methods below findAllEmployment, getAllWorkerAddressDetailsByWorkerId and it do return the proper response. Not sure what is wrong when I have combined them.
WorkerDTO.java
#Builder
#NoArgsConstructor
#AllArgsConstructor
#Data
#ToString(includeFieldNames = true)
public class WorkerDTO {
...
private Flux<WorkerAddressDTO> workerAddress;
}
ServiceImpl.java
#Override
public Flux<WorkerDTO> method() {
Flux<EmploymentDTO> employmentDTOFlux = findAllEmployment();
Flux<WorkerDTO> workerDTOFlux = getWorkerDetailsWithEmploymentStatus(employmentDTOFlux);
return workerDTOFlux.flatMap(workerDTO -> {
workerDTO.setWorkerAddress(getAllWorkerAddressDetailsByWorkerId(workerDTO.getWorkerId()).map(workerAddressDTO -> workerAddressDTO));
return Flux.just(workerDTO);
});
}
Current Response:
[
{
"xyz": "abc",
"workerAddress": {
"scanAvailable": true,
"prefetch": -1
}
},
{
"xyz": "qwe",
"workerAddress": {
"scanAvailable": true,
"prefetch": -1
}
}
]
Expected Response:
[
{
"xyz": "abc",
"workerAddress": {
"key1": "value1",
"key2": "value2"
}
},
{
"xyz": "qwe",
"workerAddress": {
"key1": "value1",
"key2": "value2"
}
}
]
You need to do some changes. First, drop Flux inside WorkerDTO and replace it with List as follows:
#Builder
#NoArgsConstructor
#AllArgsConstructor
#Data
#ToString(includeFieldNames = true)
public class WorkerDTO {
...
private List<WorkerAddressDTO> workerAddress;
}
Then, you need to change your ServiceImpl code as follows:
#Override
public Flux<WorkerDTO> method() {
Flux<EmploymentDTO> employmentDTOFlux = findAllEmployment();
Flux<WorkerDTO> workerDTOFlux = getWorkerDetailsWithEmploymentStatus(employmentDTOFlux);
return workerDTOFlux.flatMap(workerDTO -> {
return getAllWorkerAddressDetailsByWorkerId(workerDTO.getWorkerId()).collectList()
.map(workerAddresses -> workerDTO.setWorkerAddress(workerAddresses));
});
}
I would like to implement a custom deserializer for our REST API that is not only used by Java application. Therefore I don't want to have Jackson putting type information into the serialized JSON.
I'm currently struggling with deserializing CollectionExpand since it contains a list data of specific ResourceModel.
public class EntityModel<R extends ResourceModel> implements Serializable {
private R data;
private List<ResourceLink> links;
private List<CollectionExpand> expands;
}
public class CollectionExpand {
private String name;
// Resource Model is an interface
private Collection<ResourceModel> data;
}
ResourceModel is an interface an each CollectionExpand contains a collection of one type of ResourceModel per name.
For example a json output could look like this.
{
"data": {},
"links": [],
"expand": [
{
"name": "photos",
"data": [
{
"id": 12,
"name": "hello.jpg"
},
{
"id": 12,
"name": "hello.jpg"
}
]
},
{
"name": "persons",
"data": [
{
"id": 783378,
"name": "Peter",
"age": 12
},
{
"id": 273872,
"name": "Maria",
"age": 77
}
]
}
]
}
As you can see each name contains the same type of resource model. photos contains PhotoResourceModel and person contains PersonResourceModel.
I started to implement my custom Jackson Deserializer
public class CollectionExpandDeserializer extends StdDeserializer<CollectionExpand> {
public CollectionExpandDeserializer() {
super(CollectionExpand.class);
}
#Override
public CollectionExpand deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
CollectionExpand collectionExpand = new CollectionExpand();
if (Objects.equals(p.nextFieldName(), "name")) {
collectionExpand.setName(p.nextTextValue());
}
if (Objects.equals(p.nextFieldName(), "data")) {
// depending on the field name I would like to delegate the deserialization to a specific type.
if (name.equals("photos") {
// how to do this?
collectionExpand.setData(/* deserialize to a list of PhotoResource */);
}
}
return collectionExpand;
}
I'm current stuck on how can I delegate telling Jackson to deserialize this as a PhotoResource list.
In general is this the right approach or is there another way to do it (without putting any Jackson meta data into the JSON while serialization)?
I have ended up implementing my custom deserializer as below
#Override
public CollectionExpand deserialize(JsonParser p, DeserializationContext ctx) throws IOException {
JsonNode node = ctx.readTree(p);
CollectionExpand collectionExpand = new CollectionExpand();
collectionExpand.setName(node.get("name").asText());
ArrayNode data = node.withArray("data");
Iterator<JsonNode> iterator = data.iterator();
while (iterator.hasNext()) {
Class<? extends ResourceModel> aClass = resolveClass(collectionExpand.getName());
if (aClass != null) {
JsonNode jsonNode = iterator.next();
collectionExpand.getData().add(p.getCodec().treeToValue(jsonNode, aClass));
}
}
return collectionExpand;
}
private Class<? extends ResourceModel> resolveClass(String name) {
if ("contents".equals(name)) {
return ContentsGetResourceModel.class;
} else if ("tags".equals(name)) {
return TagsGetResourceModel.class;
} else {
return null;
}
}
I took my a while to understand how to deserialize a JsonNode/TreeNode into a specific type. In the end I learned that this can be basically done by using the parsers codec.
PhotoResource photoResource = p.getCodec().treeToValue(jsonNode, PhotoResource.class);
I have a JSON that looks more or less like this:
{
"modules": {
"someExistingModule": {
"name": "pug",
...
},
"randomExistingModule": {
"type": "cat",
...
},
"myNewModule": { // <----- I care about this module. Note that this is NOT an array
"modules": {
"img1": {
"type": "image",
"url": "https://some/random/image,
"altText": "Some image description
},
"img2": {
"type": "image",
"url": "https://some/random/image,
"altText": "Some image description
},
"img3": {
"type": "image",
"url": "https://some/random/image,
"altText": "Some image description
},
"txt1": { // <------ Updated JSON
"type": "text",
"content": "Hello world 1"
},
"txt2": {
"type": "text",
"content": "Hello world 2"
},
...
}
}
Inside myModule there can be N number of imgN objects and txtN. I need to parse this dynamically.
My current Response class looks like this:
public class MyModuleResponse extends SomeResponseClass
{
#Override
public void parse(InputStream data)
{
T responseBody = readJsonStream(data, MyModuleResponseBody.class());
MyModuleDataParser.parse(responseBody);
}
MyModuleDataParser.java
...
public static MyModuleDataParser parse(#Nullable MyModuleResponseBody body)
{
parseSomeExistingModule();
parseRandomExistingModule();
parseMyNewModule(); // <--- This is the new module I'm trying to parse. Currently, this method is empty.
}
MyModuleResponseBody.java
public class MyModuleResponseBody
{
public Modules modules;
public static class Modules
{
SomeExistingModule someExistingModule;
RandomExistingModule randomExistingModule;
MyNewModule myNewModule; // <----- My new module
}
public static class SomeExistingModule
{
String name;
...
}
public static class RandomExistingModule
{
String type;
...
}
public static class MyNewModule
{
public ??? modules; // <--- Trying to define the Type here. Something like List<MyImageModule>. But, it won't work
}
MyImageModule.java
public class MyImageModule extends Module // <---- Update: This class now extends a generic Module class
{
private String url;
private String altText;
}
MyTextModule.java <---- New Module
public class MyTextModule extends Module // New class
{
private String content;
}
Module.java
public class Module // <----- New parent class
{
protected String type;
}
How do I create a list of MyImageModule from myNewModule? I believe I need to use some kind of TypeAdapter from Gson library. But, I'm not familiar how to do this inside an existing response.
Use Map<String, MyImageModule>, in fact, a hashmap to solve the issue of non-list modules object in the json.
public static class MyNewModule {
public Map<String, MyImageModule> modules; // initialize as a hashmap
}
How can I make my RequestBody accept a model with object fields that may or may not be included?
This is the Restcontroller endpoint I’m calling
#PatchMapping(value = "/projects/update/{projectNumber}")
public ResponseEntity<Object> updateProject(#PathVariable int projectNumber, #RequestBody RequestReviewUpdate rru)
{
return reviewUpdateService.updateReview(projectNumber, rru);
}
Here is the model #RequestBody is accepting
public class RequestReviewUpdate
{
private UpdateProject project;
private List<UpdateHlsd> reviews;
private List<UpdateProjectLeadership> stakeHolders;
public UpdateProject getProject()
{
return project;
}
public List<UpdateHlsd> getReviews()
{
return reviews;
}
public List<UpdateProjectLeadership> getStakeHolders()
{
return stakeHolders;
}
}
I want to be able to send a JSON could contain all object field, or some.
My JSON body could look something like this...
{
"project": {
"type": "HLSD"
},
"reviews": [
{
"id": 570,
"requestedBy": "Name here",
"notes":"test"
}
],
"stakeHolders": [
{
"id": 1088,
"projectResource": "sid"
}
]
}
Or this...ect
{
"reviews": [
{
"id": 570,
"requestedBy": "name",
"notes":"test"
}
}
Or any other possible combinations.
Just make your RequestReviewUpdate optional, like:
#PatchMapping(value = "/projects/update/{projectNumber}")
public ResponseEntity<Object> updateProject(#PathVariable int projectNumber, #RequestBody(required=false) RequestReviewUpdate rru) {
return reviewUpdateService.updateReview(projectNumber, rru);
}
This will make your parameter optional, either entirely or partially. I.e. any member of the object you receive as an argument, might be present or absent.
I am writing a spring websocket application with StompJS on the client side.
On the client side I am intending to send a List of objects and on the server side when it is mapping into java object, it converts itself into a LinkedHashMap
My client side code is
function stomball() {
stompClient.send("/brkr/call", {}, JSON.stringify(listIds));
}
Listids looks like
[{
"path": "/a/b/c.txt",
"id": 12
}, {
"path": "/a/b/c/d.txt",
"id": 13
}]
List Id object looks like
public class ListId {
private String path;
private Long id;
//getters and setters...
}
The Controller looks like this
#MessageMapping("/call" )
#SendTo("/topic/showResult")
public RetObj process(List<ListId> listIds) {
if (!listIds.isEmpty()) {
for(ListId listId: listIds) {
}
}
So I get a java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.blah.ListId
However when I do the same with normal Spring Controller with RestMapping it works fine, Is there anything with springs MessageMapping annotation that maps objects to java differently than the traditional way
I am not sure why is not casting to ListID
I changed it from a List to an Array and it works! Here is what I did
#MessageMapping("/call" )
#SendTo("/topic/showResult")
public RetObj process(ListId[] listIds) {
if (!listIds.isEmpty()) {
for(ListId listId: listIds) {
}
}
Thanks to this question ClassCastException: RestTemplate returning List<LinkedHashMap> instead of List<MymodelClass>
I know this question has already been answered but here's another solution.
To get Jackson to convert your JSON array to list you'll have to wrap it in another object and serialize/deserialize that object.
So you'll have to send following JSON to server
{
list: [
{
"path": "/a/b/c.txt",
"id": 12
}, {
"path": "/a/b/c/d.txt",
"id": 13
}
]
}
List is wrapped into a another object.
Following is the wrapper class
class ServiceRequest {
private List<ListId> list;
public List<ListId> getList() {
if (list == null) {
list = new ArrayList<ListId>();
}
return list;
}
}
and the message method will become
#MessageMapping("/call" )
#SendTo("/topic/showResult")
public RetObj process(ServiceRequest request) {
List<ListId> listIds = request.getList();
if (!listIds.isEmpty()) {
for(ListId listId: listIds) {
}
}
}
Test Code
import java.util.ArrayList;
import java.util.List;
import org.codehaus.jackson.map.ObjectMapper;
public class TestJackson {
public static void main(String[] args) throws Exception {
System.out.println("Started");
String json = "{\"list\":[{\"path\":\"/a/b/c.txt\",\"id\":12},{\"path\":\"/a/b/c/d.txt\",\"id\":13}]}";
ObjectMapper mapper = new ObjectMapper();
ServiceRequest response = mapper.readValue(json.getBytes("UTF-8"), ServiceRequest.class);
for(ListId listId : response.getList()) {
System.out.println(listId.getId() + " : " + listId.getPath());
}
}
public static class ServiceRequest {
private List<ListId> list;
public List<ListId> getList() {
if (list == null) {
list = new ArrayList<ListId>();
}
return list;
}
}
public static class ListId {
private String path;
private String id;
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
}
Test Output
Started
12 : /a/b/c.txt
13 : /a/b/c/d.txt