community!
I got the following JSON response from some API:
[
[
[
{
"key": [
"1",
"test1"
],
"value": 1582890257944
},
{
"key": [
"2",
"test2"
],
"value": 1582888081654
},
{
"key": [
"3",
"test3"
],
"value": 1582884771691
}
]
]
]
I should create classes to map this JSON to Java classes
Previously I got the following JSON:
[
{
"key": [
"test1"
],
"value": 1
},
{
"key": [
"test2"
],
"value": 2
}
]
and for this JSON I've created a simple class:
public class SomeClass {
private List<String> key;
private int value;
}
and Jackson mapped it correct without any problems...
Please help me, what's structure I need for class/classes?
I tried to write something like that:
List<String> params = new ArrayList<>();
params.add("1");
params.add("test1");
SomeClass someClass = new SomeClass();
someClass.setKey(params);
someClass.setValue(1L);
List<SomeClass> arrays = new ArrayList<>();
arrays.add(someClass);
arrays.add(someClass);
List<List<SomeClass>> arrayLists = new ArrayList<>();
arrayLists.add(arrays);
List<List<List<SomeClass>>> threeLists = new ArrayList<>();
threeLists.add(arrayLists);
Gson gson = new GsonBuilder().setPrettyPrinting().create();
String prettyJson = gson.toJson(threeLists);
System.out.println(prettyJson);
And got the same JSON that I had from response...
Should I create class with the next structure?
List<List<List<String>>> key;
long value;
but I got error from jackson:
Exception in thread "main" com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of main.entity.SomeClass out of START_ARRAY token
at [Source: (StringReader); line: 2, column: 5] (through reference chain: java.lang.Object[][0])
Using List<List<List<String>>> key will not work since the Json structure is List<List<List<SomeClass>>> as you have it in your sample code.
You can use Jackson TypeReference class to deserialize. Sample code using jackson-databind.
public static void main(String[] args) {
ObjectMapper mapper = new ObjectMapper();
String json = "[[[{\"key\":[\"1\",\"test1\"],\"value\":1},{\"key\":[\"1\",\"test1\"],\"value\":1}]]]";
TypeReference<List<List<List<SomeClass>>>> typeRef = new TypeReference<List<List<List<SomeClass>>>>() {
};
try {
List<List<List<SomeClass>>> someClassList = mapper.readValue(json, typeRef);
System.out.println(someClassList);
} catch (Exception ex) {
ex.printStackTrace();
}
}
Related
I have this method which should return different objects from JSON, depending on the type of class in the argument.I tryed it to return a list of objects based on the argument, but I get only LinkedHashMap into ArrayList.
I searched a lot, but everywhere in the solutions the class type is hard-coded.
Is there a way to solve this problem without hard code?
public static <T> List<T> getObjects(Class<T> c) {
CloseableHttpClient rest = HttpClientSessionSingleton.getInstance().getHttpClient();
String urlRequest = (host + "/" +
c.getSimpleName().toLowerCase() + "s");
HttpGet httpGet = new HttpGet(urlRequest);
try (CloseableHttpResponse response = rest.execute(httpGet)) {
HttpEntity entity = response.getEntity();
String jsonString = EntityUtils.toString(entity);
List<T> listObjectFromJson = new ObjectMapper().readValue(jsonString, new TypeReference<List<T>>(){});
return listObjectFromJson;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
I want to just pass the class type and get objects through one method.
[
{
"id": "73cbc0b5-3dd5-49c4-97cb-6225a19122b5",
"name": "Management",
"fields": [
{
"id": "c2d740d5-4d47-42ae-b616-977b40327812",
"name": "newField1"
}
]
},
{
"id": "dd74384b-717d-4368-b0e4-3f441d5b1ffc",
"name": "IT",
"fields": []
},
{
"id": "03304335-d7d7-46ca-8075-8d5e9feb43c6",
"name": "hhh",
"fields": []
},
{
"id": "e11b4c3f-080e-490d-8ef4-ea301d551a5d",
"name": "NEWWWWW",
"fields": []
},
{
"id": "fec7eeb0-0845-49be-be14-6cdb5fcd3575",
"name": "NEWWWWW",
"fields": []
},
{
"id": "50dfea14-f30a-448c-99df-10bf01d088fa",
"name": "NEWWWWW",
"fields": []
},
{
"id": "a4a1224e-7c66-484c-ae87-dc2ecc058c36",
"name": "NEWWWWW",
"fields": []
}
]
I get this exception when my object has a relationship
Unrecognized field "fields" (class model.orm.Department), not marked as ignorable (2 known properties: "id", "name"])
at [Source: (String)"[{"id":"73cbc0b5-3dd5-49c4-97cb-6225a19122b5","name":"Management","fields":[{"id":"c2d740d5-4d47-42ae-b616-977b40327812","name":"newField1"}]},{"id":"dd74384b-717d-4368-b0e4-3f441d5b1ffc","name":"IT","fields":[]},{"id":"03304335-d7d7-46ca-8075-8d5e9feb43c6","name":"hhh","fields":[]},{"id":"e11b4c3f-080e-490d-8ef4-ea301d551a5d","name":"NEWWWWW","fields":[]},{"id":"fec7eeb0-0845-49be-be14-6cdb5fcd3575","name":"NEWWWWW","fields":[]},{"id":"50dfea14-f30a-448c-99df-10bf01d088fa","name":"NEWWWWW","fie"[truncated 84 chars]; line: 1, column: 77] (through reference chain: java.util.ArrayList[0]->model.orm.Department["fields"])
at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from
You can construct a new JavaType parametric type passing as an argument the List.class to the ObjectMapper.html#getTypeFactory method like below:
public static <T> List<T> getObjects(Class<T> c) throws IOException {
//omitted the lines before creating the mapper including the jsonstring
ObjectMapper mapper = new ObjectMapper();
JavaType type = mapper.getTypeFactory().constructParametricType(List.class, c);
return mapper.readValue(jsonString, type);
}
I have an object nested inside another object in Json file. I want to map this object with fields to a Model class.
{
"code": 200,
"time": "2019-09-05T07:09:44.228+0000",
"data": {
"statuses": [
{
"statusType": "IN_PROGRESS",
"statusTimestamp":"019-09-05T17:04:54+1000"
},
{
"statusType": "SENT",
"statusTimestamp":"2019-09-05T21:04:55+1000"
},
{
"statusType": "OPENED",
"statusTimestamp":"2019-09-05T23:04:55+1000"
},
{
"statusType": "INTERACTION_ID_RECEIVED",
"statusTimestamp":"2019-09-06T00:04:55+1000"
}
]
},
"status": 200,
"message": null,
"errors": null,
}
I want to map the statusType and TimeStamp to a custom model class.
Model Class:
public class Model{
private String statusType;
private DateTime statusTimestamp;
public Model(String statusType, String statusTimestamp) {
this.statusType=statusType;
this.statusTimestamp=new DateTime(statusTimestamp);
}
public String getStatusType() {
return statusType;
}
public void setStatusType(String statusType) {
this.statusType = statusType;
}
public DateTime getStatusTimestamp() {
return statusTimestamp;
}
public void setStatusTimestamp(String statusTimestamp) {
this.statusTimestamp = new DateTime(statusTimestamp);
}
}
I want to map the statuses to this model class and store these objects in a link something like this
List statuses = ParsedJson.read("$..['statuses'][*]", List.class)
If you don't want to model the entire response, you could use Jackson to parse the JSON into tree nodes and then map only the parts you care about:
ObjectMapper mapper = new ObjectMapper();
JsonNode rootNode = mapper.readTree(json);
JsonNode statusesNode = rootNode.path("data").path("statuses");
List<Status> statuses = mapper.convertValue(statusesNode,
new TypeReference<List<Status>>(){});
I saw 2 errors in the json string fixing it should help you to create Object using java or any other language easily.
line 12: " was missing
line 26: invalid placement of ,
Json after fixing issues
{
"code": 200,
"time": "2019-09-05T07:09:44.228+0000",
"data": {
"statuses": [
{
"statusType": "IN_PROGRESS",
"statusTimestamp":"019-09-05T17:04:54+1000"
},
{
"statusType": "SENT",
"statusTimestamp":"2019-09-05T21:04:55+1000"
},
{
"statusType": "OPENED",
"statusTimestamp":"2019-09-05T23:04:55+1000"
},
{
"statusType": "INTERACTION_ID_RECEIVED",
"statusTimestamp":"2019-09-06T00:04:55+1000"
}
]
},
"status": 200,
"message": null,
"errors": null
}
I've been trying to get a list of all reservations from JSON using GSON but keep getting an error. Am I doing something wrong? If yes then how should I fix this?
My try:
Gson gson = new Gson();
Wrapper reservations = gson.fromJson(response.toString(), Wrapper.class);
Class:
class Wrapper{
Long id;
Long personId;
List<Long> SeatsIDs;
}
PS Is there a solution in GSON to get rid of all the "links"?
{
"links": [
{
// a lot of stuff
}
],
"content": [
{
"id": 1,
"personID": 12335,
"seatsIDs": [
5,
7,
4
],
"links": [
{
// a lot of stuff
},
{
// a lot of stuff
}
]
},
{
"id": 2,
"personID": 77777,
"seatsIDs": [
1,
2,
3
],
"links": [
{
// a lot of stuff
},
{
// a lot of stuff
}
]
}
]
}
We do not have a description of your error. But from what I see you would like to deserialize the each entry from the content array. However you ask GSON to deserialize the full response.
One possible solution will be to create a class structure that looks like your Json:
// Getters and setters omitted
class Response {
List<Link> links;
List<Wrapper> content;
}
// ...
Response response = gson.fromJson(response.toString(), Response.class);
Wrapper first = response.getContent().get(0);
I need help in the logic for transforming one json file to another json file. I am trying to achieve this in mule without dataweave in the custom java component.
I want to convert a linear json to nested json, The input data is a linear json containing the details of all files and directory in particular FTP server. The output Json file should be able to nest the files and directory based on the root directory. Here is the example of input and output json.
{
"InputJson": [
{
"type": "dir",
"id": "RootDir",
"name": "abcd",
"Dir": "/abcd"
},
{
"type": "dir",
"name": "Folder1",
"Dir": "/abcd/Folder1",
"id": "XXXXX"
},
{
"type": "file",
"name": "Folder1SubFolder1",
"Dir": "/abcd/Folder1/Folder1SubFolder1",
"id": "XXXXXX"
},
{
"type": "dir",
"name": "Folder2",
"Dir": "/abcd/Folder2"
"id": "XXXXXX"
},
{
"type": "dir",
"name": "Folder2SubFolder1",
"Dir": "/abcd/Folder2/Folder2SubFolder1"
"id": "XXXXXX"
},
{
"type": "file",
"name": "Folder2SubFolder1SubFolder1",
"Dir": "/abcd/Folder2/Folder2SubFolder1/Folder2SubFolder1SubFolder1"
"id": "XXXXXX"
}
]
}
Output
{
"id": "RootDir",
"value": "Files",
"type": "folder"
"OutData": [{
"value": "Folder1",
"OutData": [{
"value": "Folder1SubFolder1"
}
]
}
]
"OutData": [{
"value": "Folder2",
"OutData": [{
"value": "Folder2SubFolder1",
"OutData":[{
"value": "Folder2SubFolder1SubFolder1",
}]
}
]
}
]
the logic
1. CREATE (java) `outputElemtsList` = []
2. FOR EACH (json) `inputElement` IN `InputJson`
3. CREATE (java) `outputElemt`
4. ADD `outputElement` TO `outputElemtsList`
5. IF `outputElement` HAS `parent`
6. ADD `outputElement` TO `parent`.outData
7. CONVERT `outputElemtsList`[0] TO `Json`
assuming, the list in InputJson, is ordered in the same as the sample, (the child never come before their parent)
if not, you'll need to add some checks as:
3. create `outputElement` if not in `outputElemtsList`; else continue
6. create `parent` if not in `outputElemtsList`
in practice
you can use a Json parser, such jakson, to:
// parse InputJson, to Java Objects
Map<String, Object> rootNode = mapper.readValue(jsonString, Map.class);
// ... implement the logic ...
// serialize a java Object into Json
String outputJson = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(routOutputs);
the code
updated to distinguish between file and folders(dir)
1- OutputElement class
public class OutputElement {
String id, value, type;
public void addOutData(OutputElement outputElement) {}
// constructor, accessors ...
}
1.2- class OutputDir extends OutputElement
public class OutputElement {
List<OutputElement> outData = new ArrayList<>();
#Override
public void addOutData(OutputElement outputElement) {
this.outData.add(outputElement);
}
}
2- Main class : LinearToNestedJson
method to check if outputElements List contains an outputElement
public static boolean contains(List<OutputElement> outputElements, String value) {
for (OutputElement outputElement : outputElements) {
if (outputElement.getValue().equals(value))
return true;
}
return false;
}
main method
public static void main(String args[]) {
JacksonTester tester = new JacksonTester();
try {
ObjectMapper mapper = new ObjectMapper();
String jsonString = IN_JSON;
#SuppressWarnings("unchecked")
Map<String, Object> rootNode = mapper.readValue(jsonString, Map.class);
#SuppressWarnings("unchecked")
List<Map<String, Object>> inputElemnts =
(ArrayList<Map<String, Object>>) rootNode.getOrDefault("InputJson", null);
List<OutputElement> outputElements = new ArrayList<>();
for (Map inputElemnt : inputElemnts) {
String fullpath = (String) inputElemnt.get("Dir");
String[] tree = fullpath.substring(1).split("/");
final int deepth = tree.length;
String dirName = tree[deepth - 1];
final String value = (String) inputElemnt.get("name");
final String id = (String) inputElemnt.get("id");
String type = (String) inputElemnt.get("type");
OutputElement outputElement;
if (type != null && type.equals("dir")) {
outputElement = new OutputDir();
} else {
if(type==null) type = "file";
outputElement = new OutputElement();
}
outputElement.setValue(value);
outputElement.setId(id);
outputElement.setType(type);
if (!contains(outputElements, value)) {
outputElements.add(outputElement);
}
if (deepth > 1) {
String parentName = tree[deepth - 2];
for (OutputElement element : outputElements) {
if (element.getValue().equals(parentName)) {
element.addOutData(outputElement);
}
}
}
// for (int i = 0; i < deepth -1; i++) {
// System.out.println(tree[i]);
// }
}
OutputElement routOutputs = outputElements.get(0);
String outputJson = mapper.writerWithDefaultPrettyPrinter()
.writeValueAsString(routOutputs);
System.out.println(outputJson);
} catch (JsonParseException | JsonMappingException e) {
} catch (IOException e) {
}
}
it's output, for the given input (after validation)
{
"id" : "RootDir",
"value" : "abcd",
"type" : "dir",
"outData" : [ {
"id" : "XXXXX",
"value" : "Folder1",
"type" : "dir",
"outData" : [ {
"id" : "XXXXXX",
"value" : "Folder1SubFolder1",
"type" : "file"
} ]
}, {
"id" : "XXXXXX",
"value" : "Folder2",
"type" : "dir",
"outData" : [ {
"id" : "XXXXXX",
"value" : "Folder2SubFolder1",
"type" : "dir",
"outData" : [ {
"id" : "XXXXXX",
"value" : "Folder2SubFolder1SubFolder1",
"type" : "file"
} ]
} ]
} ]
}
Use groupBy - that's exactly what you need.
Here is code:
%dw 1.0
%output application/json
---
items : payload.InputJson groupBy $.id pluck {
id: $$,
values: $
}
Here is result:
I have a POJO like this
public class Pojo {
...
public static String toJson(ArrayList<Pojo> pojos) {
Gson gson = new Gson();
return gson.toJson(pojos);
}
}
The output is:
[
{
"arrival": "19:12:30",
"typeOfDay": "regular",
"stopCode": "CMPZ",
"route": "B",
"id": 1
},
{
"arrival": "19:13:30",
"typeOfDay": "regular",
"stopCode": "AVSV",
"route": "B",
"id": 2
}
]
But what I want is this:
{
"pojos": [
{
"arrival": "19:12:30",
"typeOfDay": "regular",
"stopCode": "CMPZ",
"route": "B",
"id": 1
},
{
"arrival": "19:13:30",
"typeOfDay": "regular",
"stopCode": "AVSV",
"route": "B",
"id": 2
}
]
}
How I can do it? I'm using Gson 2.2.4
Change your method like this:
public static String toJson(List<Pojo> pojos) {
Gson gson = new Gson();
Map m = new TreeMap();
m.put("pojos", pojos);
return gson.toJson(m);
}
BTW, note that I changed signature, prefer an interface (List) instead of an implementation (ArrayList) into your methods.
I have no idea what Gson is, but I imagine something like this would work...
return gson.toJson({pojos:pojos});