Serializing multiple tiers of XML elements - java

Let's say I'm trying to create an XML document out of an object. Is this possible using JAXB annotations on a single Food class, or do I need to create inner classes for Cost and Flavor?
I know I can use #XmlElement or #XmlAttribute to set up immediate children of my root element. However, I'm not sure if/how to create the <cost> and <Flavor> tags as I show here.
<Food>
<cost amt=13.5 unit=USD/>
<Flavor spicy=5>It tastes good</Flavor>
</Food>
#XmlRootElement("Food")
public class Food {
private float amount;
private String units;
private String flavorType;
private STring flavorDescription;
}

Add a new Java class Cost:
public class Cost
{
#XmlAttribute
double amt;
#XmlAttribute
String unit;
}
And exdend class Food
#XmlRootElement
public class Food {
private float amount;
private String units;
private String flavorType;
private String flavorDescription;
private Cost cost;
...

you could also use something like this for Flavor class
public class Flavor {
private long spicy;
private String shortDesc;
#XmlValue
public String getShortDesc() {
return shortDesc;
}
public void setShortDesc(String shortDesc) {
this.shortDesc = shortDesc;
}
#XmlAttribute
public Long getSpicy() {
return spicy;
}
public void setSpicy(long spicy) {
this.spicy= spicy;
}
}

Related

JSON to java object returing LinkedHashMap

I have below json string :-
{"name":"Test","sortlist":[],"filterlist":[{"fieldname":"regions_id","operator":"equals","value":{"id":1,"code":"HIGH","description":"HIGH Region","comment":"High Region","active":true}}]}
and Java class as below :-
#JsonSerialize
#JsonDeserialize
public class ItemFilter implements Serializable {
private String name;
private List<FieldFilter> filterlist = new ArrayList<FieldFilter>();
}
public class FieldFilter implements Serializable {
private static final long serialVersionUID = 1L;
private String fieldname;
private String operator;
private Object value;
}
and my convert method as below :-
public static ItemFilter convertItemFilter(String item) {
ObjectMapper mapper = new ObjectMapper();
try {
ItemFilter itemFilter = mapper.readValue(item, new TypeReference<ItemFilter>(){});
return itemFilter;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
ItemFilter domain is getting converted correctly but in private Object value; field i am getting LinkedHashMap i want to get an simple object and later i will type cast it.
Can someone please guide me how to escape LinkedHashMap and get an simple Java Object in variable?
i cant use hard coding Object type because its a generic pojo which can have any object type. hard coding will make this pojo very bigger and frontend also need to change for it. So that why i have used Object as data type.
The following class structure should return the JSON to "YourObject"
public class YourObject{
private String name;
private List<String> sortList;
private List<Filter> filterList;
public static class Filter{
private String fieldname;
private String operator;
private Value value;
}
public static class Value{
private Integer id;
private String code;
private String description;
private String comment;
private Boolean active;
}
}
Then use the following to read it into the object:
YourObject itemFilter = mapper.readValue(item, YourObject.class);

Jackson XML: nested field deserialization

I have the following xml
<MyPojo>
<name>Jason</name>
<age>25</age>
<meta>
<occupation>Engineer</occupation>
</meta>
</MyPojo>
I need to deserialize it to the following POJO:
public class MyPojo {
private String name;
private int age;
private String occupation;
}
The problem here is that occupation is wrapped within meta element
You need one more object:
public class MyPojo {
private String name;
private int age;
private Meta meta;
}
public class Meta{
private String occupation;
}
My idea is to replace occupation with an own class. Something like myMeta or whatever you want to call it(be aware in your case like the xml says: meta). This class should cotain the field occupation:
public class Meta
{
private String occupation;
}
After that you only have to add a new field of your new class e.g. myMeta to myPojo. Something like this:
public class MyPojo
{
private String name;
private int age;
private Meta meta;
}
this should avoid
that occupation is wrapped within meta element
Hope that helps!

jackson serialization of nested objects

I have problem with jackson serialization of object by its interface.
I have class
class Point implements PointView {
private String id;
private String name;
public Point() {
}
public Point(String id, String name) {
this.id = id;
this.name = name;
}
#Override
public String getId() {
return id;
}
public String getName() {
return name;
}
}
which implements
interface PointView {
String getId();
}
and have class
class Map implements MapView {
private String id;
private String name;
private Point point;
public Map() {
}
public Map(String id, String name, Point point) {
this.id = id;
this.name = name;
this.point = point;
}
#Override
public String getId() {
return id;
}
public String getName() {
return name;
}
#JsonSerialize(as = PointView.class)
public Point getPoint() {
return point;
}
}
which implements
interface MapView {
String getId();
Point getPoint();
}
And have class
class Container {
private Map map;
public Container() {
}
public Container(Map map) {
this.map = map;
}
#JsonSerialize(as = MapView.class)
public Map getMap() {
return map;
}
}
I want serialize Container with Jackson and get result
{"map":{"id":"mapId","point":{"id":"pointId"}}}
But in fact I get result
{"map":{"id":"mapId","point":{"id":"pointId","name":"pointName"}}}
that have property "name" in nested object "point" although I specified serializition type of Point in Map (#JsonSerialize(as = PointView.class)). Interface PointView dont have method getName, but in result exists field "name" of Point.
If I remove annotation (#JsonSerialize(as = MapView.class)) from method getMap in class Container I get result
{"map":{"id":"mapId","name":"mapName","point":{"id":"pointId"}}}
Now point dont have property "name", but map have.
How can I get result
{"map":{"id":"mapId","point":{"id":"pointId"}}}
?
To get the desired result also the same method in interface must be annotated by #JsonSerialize
interface MapView {
String getId();
#JsonSerialize(as = PointView.class)
Point getPoint();
}
You can annotate the method like this:
#JsonIgnore
public String getName() {
return name;
}
Or if you want specific serialization in this use case, but normal serialization in others, you can use a #JsonView (see doc).
The reason it's serializing out the name is that the instance has the accessor getName(), even though interface does not.
Yes, you can use
#JsonSerialize(as=MyInterface.class)
public class ConcreteClass implements MyInterface { .... }
either on implementation class (as above), or on property that has value.

Defining inner classes in AppEngine Datastore (Objectify)

In AppEngine I need to have an entity Diagram that contains an id, title and a variable list of elements of inner class Box, each one with id and description.
Please find below the definition. However, at time of defining the EntityProxy List getter and setter: "The type java.util.List<Box> cannot be used here".
DIAGRAM.java
#Entity
public class Diagram extends DatastoreObject {
public class Box {
private String boxId;
private String description;
public String get_id() {
return boxId;
}
public void set_id(String boxId) {
this.boxId = boxId;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
#Indexed private String diagramId; // Primary key
#Indexed private String title;
#Embedded private List<Box> boxes;
public String get_id() {
return diagramId;
}
public void set_id(String diagramId) {
this.diagramId = diagramId;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public void setBoxes(List<Box> boxes) {
this.boxes = boxes
}
public List<Box> getBoxes() {
return boxes;
}
}
DIAGRAMPROXY.java
[...]
List<Box> getBoxes();
void setBoxes(List<Box> boxes);
[...]
Your inner class must be static. Nonstatic inner classes have an implicit link to an instance of the outer class, which would be really confusing from the perspective of loading and saving entities to the datastore.
Confusing, you have a Collection<Box> in the Box class? Doesnt sound right.. Anyways the inner Box class must be market static or be moved to a different file. Use the #Embed (version 4.0) annotation on the Box class.
Also, assuming DatastoreObject is the base of all your entities, you can make DatastoreObject as an #Entity and all its sub classes as an #EntitySubClass (index = true). Obviously all sub entities would be be saved under the same 'kind' (DatastoreObject) in the datastore.

How to deserialize JSON into java objects using Jackson

I have a rather JSON response coming back from a solr instance....
{"responseHeader":
{"status":0,"QTime":1,"params":{"sort":"score asc","fl":"*,score",
"q":"{! score=distance}","wt":"json","fq":"description:motor","rows":"1"}},
"response":{"numFound":9,"start":0,"maxScore":6.8823843,"docs":
[{"workspaceId":2823,"state":"MN","address1":"1313 mockingbird Lane",
"address2":"","url":"http://mydomain.com/","city":"Minneapolis",
"country":"US","id":"399068","guid":"","geo":["45.540239, -98.580473"],
"last_modified":"2012-12-12T20:40:29Z","description":"ELEC MOTOR",
"postal_code":"55555","longitude":"-98.580473","latitude":"45.540239",
"identifier":"1021","_version_":1421216710751420417,"score":0.9288697}]}}
And I'm trying to map that to a java object:
public class Item extends BaseModel implements Serializable {
private static final long serialVersionUID = 1L;
protected Integer workspaceId;
protected String name;
protected String description;
protected String identifier;
protected String identifierSort;
protected Address address;
protected String url;
/** getters and setters eliminated for brevity **/
}
public class Address implements Serializable {
private static final long serialVersionUID = 1L;
protected String address1;
protected String address2;
protected String city;
protected String state;
protected String postalCode;
protected String country;
/** getters and setters eliminated for brevity **/
}
How do I map the address1, address2, city, state, etc... into the Address object in the Item object? I've been reading about Jackson annotations but nothing really jumps out at me as to where to begin.
If using Jackson 1.9 or higher you can use the #JsonUnwrapped annotation to handle this.
Here is an example of using it (largely lifted from Jackson's documentation):
public class Name {
private String first, last;
// Constructor, setters, getters
}
public class Parent {
private int age;
#JsonUnwrapped
private Name name;
// Constructor, setters, getters
}
public static void main(String[] args) {
try {
final ObjectMapper mapper = new ObjectMapper();
final Parent parent = mapper.readValue(new File(
"/path/to/json.txt"), Parent.class);
System.out.println(parent);
} catch (final Exception e) {
e.printStackTrace();
}
}
We ended up using Solrj - sort of.
We wrote our own SolrResult object that we fed to SolrJ like so:
List<SolrResult> solrResults = rsp.getBeans(SolrResult.class);
And then in SolrResult.java where we had complex or nested objects we just first used SolrJ annotation to get the field and then just set the value as needed...
#Field("address1")
public void setAddress1(String address1) {
this.item.getAddress().setAddress1(address1);
}
It wasn't hard just feels a bit messy, but it does work.

Categories