Jersey - Serializing a POJO with json - nested objects will be ignored - json

Question

HiAll,
i have the following problem in development branch:
If i use the jersey REST service to serialize the POJO containig a list of the nested other POJO, then this nested POJO will be NOT serialized. This problem is reproducible only in branch.
If i prototype using POJO structur liked in branch, i have no problem.
The Details:
The POJO (Domain):
public class Article {
private int id;
private int name;
// getter & setter
}
The POJO ( DTO)
public class DTO {
private List<Article> articles;
private String message;
public DTO {
articles= new ArrayList<>();
}
getArticles() {
return articles;
}
getArticlesCount() {
return articles.size();
}
public void getMessage() {
return message;
}
public String getMessage() {
return message;
}
....
}
It will be created the 1 article with id = 1 and name "firstArticle" the
The results of serialization after service call to find all articles:
in branch
*{"message":"1 article found","articlesCount":1
}*
in prototype
{
{"message":"1 article found","articlesCount":1[{"id":1,"name":"firstArticle"]}
}
i have no idia what's happened. I checked out all settings (web.xml, jersey version, etc.)

Answer 1

If you use Jackson JSON library, your POJO will be automatically handled by Jackson JSON lib to convert between JSON and POJO. You also need to add the following lines in your web.xml:
<init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>true</param-value>
</init-param>
Then in your Jersey resource class, use #Produces and #Consumes annotation to indicate the data format is JSON:
#Path("/myResource")
#Produces("application/json")
public class SomeResource {
#GET
public String doGetAsJson() {
...
}
}

Answer 2

Follow the above answer to set up Jersey POJO mappping, and then try the following nested POJO example.
Article class:
public class Article {
private int id;
private String name;
public Article(int id, String name) {
this.id = id;
this.name = name;
}
//getter and setter ...
}
The Book class that contains the Article class:
public class Book {
private List<Article> articles;
private String message;
private int articleCount;
public List<Article> getArticles() {
return articles;
}
public void setArticles(List<Article> articles) {
this.articles = articles;
setArticleCount(articles.size());
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public int getArticleCount() {
return articleCount;
}
public void setArticleCount(int articleCount) {
this.articleCount = articleCount;
}
}
Finally in the Jersey resource class NestedPojoResource:
#Path("/nested-pojo")
public class NestedPojoResource {
#GET
#Produces(MediaType.APPLICATION_JSON)
public Book getNestedPojo() {
Book book = new Book();
List<Article> articles = new ArrayList<Article>();
articles.add(new Article(1, "firstArticle"));
articles.add(new Article(2, "secondArticle"));
book.setArticles(articles);
book.setMessage(book.getArticleCount() + " articles found");
return book;
}
}
When you go to http://example.com/myappname/nested-pojo, you will see the correct JSON output which contains the nested POJO fields:
{"articles":[{"id":1,"name":"firstArticle"},{"id":2,"name":"secondArticle"}],"message":"2 articles found","articleCount":2}