All the answers on stackoverflow regarding Jackson I found deal with only single root node unwrapping for JSONs like
{
"user":
{
"name":"Sam Smith",
"age":1
}
}
The solution is to either use wrapper classes or use .withRootName("user") call like this
User user = objectMapper.reader()
.forType(User.class)
.withRootName("user")
.readValue(string);
also annotating User class with#JsonRootName(value = "user") is the option.
But is there an option to NOT use wrapper classes for JSONs with several parallel root nodes like this:
{
"user":
{
"name":"Sam Smith",
"age":1
},
"timestamp":
{
"clickpoint":"AE12",
"purchasable":"false"
}
}
. Can't find a solution for that. Jackson will throw an exception of not matching root name "timestamp" with expected "user". Thank you for help if you know the answer.
To operate with objects without named root you can deal with JsonNode like in the example below:
ObjectMapper mapper = new ObjectMapper();
JsonNode node = mapper.reader().readTree(source);
User user = mapper.treeToValue(node.get("user"), User.class);
Timestamp timestamp = mapper.treeToValue(node.get("timestamp"), Timestamp.class);
System.out.println(user.getName());
System.out.println(timestamp.getClickpoint());
In older version of Jackson instead of treeToValue() you can use readValue() with the same arguments.
Related
im using fasterxml jackson to serialize an entity in a java project, the problem im having is the following one, when the entity is converted to JSON I get something like this:
{ "#id":1
"father":{
"#id":2,
"name":"robert smith"
"country":{"#id":3, "countryId":10, "countryName":"USA"}
},
"mother":{
"#id":4,
"name":"mary dune"
"country":{#ref:3}
}
}
Father and Mother has a reference to the same Country object, but when is serialized mother only have the reference to #id:3. I know that this is done to avoid circular refernce and that kind of stuff, but in this case I need that with the country entity it doesnt use reference and just put the whole entity.
Is there some kind of annotation to achieve that? like putting an annotation in the country entity? I just want this with country and no other entity, I want the other ones to respect the ref system.
The result im looking for is something like:
{"#id":1
"father":{
"#id":2,
"name":"robert smith"
"country":{"#id":3, "countryId":10, "countryName":"USA"}
},
"mother":{
"#id":4,
"name":"mary dune"
"country":{"#id":3, "countryId":10, "countryName":"USA"}
}
}
This is the objectMapper im using:
public ObjectMapperContextResolver() {
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addSerializer(
LocalDateTime.class,
new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm")));
javaTimeModule.addSerializer(
LocalDate.class,
new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
javaTimeModule.addDeserializer(LocalDateTime.class,
new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm")));
javaTimeModule.addDeserializer(LocalDate.class,
new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
defaultMapper.registerModule(new Jdk8Module())
.registerModule(javaTimeModule)
.registerModule(new BlankStringsAsNullModule())
.setSerializationInclusion(JsonInclude.Include.NON_NULL)
.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true)
.configure(SerializationFeature.USE_EQUALITY_FOR_OBJECT_ID, true);
}
I'm working with the MarkLogic POJO Databinding Interface at the moment. I'm able to write POJOs to MarkLogic. Now I want to search those POJOs and retrieve the search results. I'm following the instructions from: https://docs.marklogic.com/guide/java/binding#id_89573 However, the search results don't seem to return the correct objects. I'm getting a JSONMappingException. Here's the code:
HashMap<String, MatchedPropertyInfo> matchedProperties = new HashMap<String, MatchedPropertyInfo>();
PropertyMatches PM = new PropertyMatches(123,"uri/prefix/location2", "uri/prefix", 1234,0,"/aKey","/aLocation",true,matchedProperties);
MatchedPropertyInfo MPI1 = new MatchedPropertyInfo("matched/property/uri1", "matched/property/key1", "matched/property/location1", true,"ValueMatch1", 12, 1*1.0/3, true);
MatchedPropertyInfo MPI2 = new MatchedPropertyInfo("matched/property/uri2", "matched/property/key2", "matched/property/location2", true,"ValueMatch2", 14, 1.0/2.0, true);
PM.getMatchedProperties().put("matched/property/prefix/location1", MPI1);
PM.getMatchedProperties().put("matched/property/prefix/location2", MPI2);
PojoRepository myClassRepo = client.newPojoRepository(PropertyMatches.class, Long.class);
myClassRepo.write(PM);
PojoQueryBuilder qb = myClassRepo.getQueryBuilder();
PojoPage<PropertyMatches> matches = myClassRepo.search(qb.value("uri", "uri/prefix/location2"),1);
if (matches.hasContent()) {
while (matches.hasNext()) {
PropertyMatches aPM = matches.next();
System.out.println(" " + aPM.getURI());
}
} else {
System.out.println(" No matches");
}
The PropertyMatches (PM) object is succesfully written to the MarkLogic database. This class contains a member: private String URI which is initiated with "uri/prefix/location2". The matches.hasContent() returns true in the example above. However, I'm getting an error on PropertyMatches aPM = matches.next();
Searching POJOs in MarkLogic and read them into your Java program requires the POJOs to have an empty constructor. In this case PropertyMatches should have public PropertyMatches(){} and MatchedPropertyInfo should have public MatchedPropertyInfo(){}
Thanks #sjoerd999 for posting the answer you found. Just to add some documentation references, this topic is discussed here: http://docs.marklogic.com/guide/java/binding#id_54408 and here: https://docs.marklogic.com/javadoc/client/com/marklogic/client/pojo/PojoRepository.html.
Also worth noting is you can have multiple parameters in the consructor, you just have to do it the Jackson way. Here are examples of two ways (with annotations and without): https://manosnikolaidis.wordpress.com/2015/08/25/jackson-without-annotations/
I'd recommend using annotations as that's built-in with Jackson. But if you want to do it without annotations, here's the code:
ObjectMapper mapper = new ObjectMapper();
// Avoid having to annotate the Person class
// Requires Java 8, pass -parameters to javac
// and jackson-module-parameter-names as a dependency
mapper.registerModule(new ParameterNamesModule());
// make private fields of Person visible to Jackson
mapper.setVisibility(FIELD, ANY);
If you want to do this with PojoRepository you'll have to use the unsupported getObjectMapper method to get the ObjectMapper and call registerModule and setVisibility on that:
ObjectMapper objectMapper = ((PojoRepositoryImpl) myClassRepo).getObjectMapper();
I want to create JSON Schema manually using GSON but i dont find any JsonSchema element support in GSON. I dont want to convert a pojo to schema but want to create schema programatically . Is there any way in GSON ? May be something like following.
**1 JsonSchema schema = new JsonSchema();
2 schema.Type = JsonSchemaType.Object;
3 schema.Properties = new Dictionary<string, JsonSchema>
4{
5 { "name", new JsonSchema { Type = JsonSchemaType.String } },
6 {
7 "hobbies", new JsonSchema
8 {
9 Type = JsonSchemaType.Array,
10 Items = new List<JsonSchema> { new JsonSchema { Type = JsonSchemaType.String } }
11 }
12 },
13};**
You may consider using everit-org/json-schema for programmatically creating JSON Schemas. Although it is not properly documented, its builder classes form a fluent API which lets you do it. Example:
Schema schema = ObjectSchema.builder()
.addPropertySchema("name", StringSchema.builder().build())
.addPropertySchema("hobbies", ArraySchema.builder()
.allItemSchema(StringSchema.builder().build())
.build())
.build();
It is slightly different syntax than what you described, but it can be good for the same purpose.
(disclaimer: I'm the author of everit-org/json-schema)
I tried to build a schema as suggested above, see Everit schema builder includes unset properties as null
I am trying to deserialize a JSON String using Jackson 2 with RestAssured (java tool for IT tests).
I have a problem. The String I am trying to deserialize is :
{"Medium":{"uuid":"2","estimatedWaitTime":0,"status":"OPEN_AVAILABLE","name":"Chat","type":"CHAT"}}
There is the object type "Medium" at the begining of the String. This cause Jackson failing during deserialization:
com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "Medium"
I've set the "IGNORE_ON_UNKNOWN_PROPERTIES" to false and then I got no exception during deserialisation. However, all of my properties are 'null' in java.
Response getAvailability -> {"Medium":{"uuid":"2","estimatedWaitTime":0,"status":"OPEN_AVAILABLE","name":"Chat","type":"CHAT"}}
### MEDIUM name -> null
### MEDIUM uuid -> null
### MEDIUM wait time -> null
### MEDIUM wait time -> null
### MEDIUM status -> null
Does anyone can help me ? (note: I can't change my input JSON string).
{
"Medium": {
"uuid": "2",
"estimatedWaitTime": 0,
"status": "OPEN_AVAILABLE",
"name": "Chat",
"type": "CHAT"
}
}
as you can see uuid and other params are part of medium object , so class in which it can be deserialized is.
class Medium
{
string name;
// specify other params also.
}
class BaseObject
{
Medium Medium;
}
and then use jackson.deserialize('json', BaseObject.class)
above i had given pseudo code
You need to put annotation
#JsonRootName("Medium")
on your bean class and configure object mapper to
mapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE).
You need a way to remove the Object name that is the part of the input JSON. Since you cannot change the input string, Use this code to change this input string to a tree and get the value of "Medium" node.
ObjectMapper m = new ObjectMapper();
JsonNode root = m.readTree("{\"Medium\":{\"uuid\":\"2\",\"estimatedWaitTime\":0,\"status\":\"OPEN_AVAILABLE\",\"name\":\"Chat\",\"type\":\"CHAT\"}}");
JsonNode obj = root.get("Medium");
Medium medium = m.readValue(obj.asText, Medium.class);
I want to access Domino data via the Domino Access Services (DAS) as REST provider in java e.g.
String url = "http://malin1/fakenames.nsf/api/data/collections/name/groups";
ObjectMapper mapper = new ObjectMapper();
JsonFactory factory = new JsonFactory();
JsonParser parser = factory.createParser(new URL(url));
JsonNode rootNode = mapper.readTree(parser);
however, I notice DAS binds the JSON in square brackets:
[
{
"#entryid":"1-D68BB54DEA77AC8085256B700078923E",
"#unid":"D68BB54DEA77AC8085256B700078923E",
"#noteid":"1182",
"#position":"1",
"#read":true,
"#siblings":3,
"#form":"Group",
"name":"LocalDomainAdmins",
"description":"This group should contain all Domino administrators in your domain. Most system databases and templates give people in this group Manager access."
},
{
"#entryid":"3-9E6EABBF405A1A9985256B020060E64E",
"#unid":"9E6EABBF405A1A9985256B020060E64E",
"#noteid":"F46",
"#position":"3",
"#read":true,
"#siblings":3,
"#form":"Group",
"name":"OtherDomainServers",
"description":"You should add all Domino servers in other domains with which you commonly replicate to this group."
}
]
How can I easily get rid of these brackets?
As already mentioned you should leave them intact. You can parse theJSON array for example with Jackson.
find an example snippet below
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.ObjectMapper;
...
String response = ... your posted string
ObjectMapper mapper = new ObjectMapper();
try {
JsonNode taskIdsjsonNode = mapper.readTree(response);
for (JsonNode next : taskIdsjsonNode) {
System.out.printf("%s: %s%n", "#entryid", next.get("#entryid"));
System.out.printf("%s: %s%n", "name", next.get("name"));
}
} catch (.... ) {
// your exception handling goes here
}
output
#entryid: "1-D68BB54DEA77AC8085256B700078923E"
name: "LocalDomainAdmins"
#entryid: "3-9E6EABBF405A1A9985256B020060E64E"
name: "OtherDomainServers"
The brackets are not nasty but a correct notation. To access the contens just use [0] in your client side script or with your JSON parser in Java you like.
Perhaps the explanation here can help:
https://quintessens.wordpress.com/2015/05/08/processing-json-data-from-domino-access-services-with-jackson/
Basically you establish a call to DAS via the Jersey client and then you parse the json via Jackson library to a map in java.
During the parsing process you can define which values you want to parse and transform them.
Take a look at the Person class...