i'm using ViewScoped in my controller but i need to do something wired..
i want to mantain the data when using that view but if i leave that view, and then return i dont want the data there!
#Component("sponsorController")
#ViewScoped
public class SponsorController implements Serializable {
private static final long serialVersionUID = 1L;
#Autowired
private SponsorClientFacade ejbFacade;
should i switch scope?or this is the right one?
i can't do want i want with this way..
My solution was specify a onclick method in the hyperlynk and that method clear all views..
Thanks for the help
Related
I'm trying to create a REST service with Spring.
Everything works until I try to add a List of object (CartItem) to my main object (Cart).
This is my main object
#Entity
#Table(name="cart")
public class Cart implements Serializable{
...
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Id
#Column(name="id")
private Integer id;
/*when I add this I get the error. If I remove this, the
REST service works*/
#OneToMany(mappedBy="cart", fetch = FetchType.EAGER)
private List<CartItem> cartItems;
//getter, setter, constructors, other fields ecc.
}
This is the object inside the List:
#Entity
#Table(name="cart_item")
public class CartItem implements Serializable{
...
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Id
#Column(name="id")
private Integer id;
#OneToOne(targetEntity = Product.class, cascade = CascadeType.ALL)
#JoinColumn(referencedColumnName="productId", name="product_id" )
private Product product;
#ManyToOne
#JoinColumn(name="cart_id", nullable=false)
private Cart cart;
//getter, setter, constructors, other fields ecc.
}
This is my controller
#RestController
#RequestMapping(value="rest/cart")
public class CartRestController {
...
#RequestMapping(value = "/", method = RequestMethod.GET)
public List<Cart> readAll() {
return cartService.read();
}
...
}
I get this error:
SEVERE: Servlet.service() for servlet [dispatcher] in context with path
[/webstore] threw exception [Request processing failed; nested exception
is org.springframework.http.converter.HttpMessageNotWritableException:
Could not write JSON: Infinite recursion (StackOverflowError); nested
exception is com.fasterxml.jackson.databind.JsonMappingException:
Infinite recursion (StackOverflowError) (through reference chain:...
I suppose that I had to manage the List inside the Cart object in a particular manner, maybe because i'm using JPA, but I still didn't find a solution on the internet.
Can anyone help me?
This is a serialization recursion problem, it happens because CartItem has a bidirectional mapping back to Cart. So what happens is that
a Cart gets serialized to JSON
all the CartItems inside it get serialized to JSON
the Cart property inside CartItem get serialized to JSON
the CartItems inside the cart get serialized to json, etc. etc.
You will probably want to exclude the CartItem.cart field from serialization by marking it with the #JsonIgnore annotation.
It is only too easy to expose far too much information to the outside world if you use JPA entities directly inside your webservices. Jackson actually has a useful feature called a JsonView which allows you to define which properties get exposed, you can even tailor it per webservice call if you want.
Never ending list? Did you mean a stackOverFlow exception?
If the situation is just like I said,then you should check something like fetch type and the entities' toString() or equal() method or something like that.
For example,there are to entities named A and B and their relationship is one to many(A is the one).If you config both of their fetchType as Eager,then when jpa query A,it will query B too.But B also contains A,so jpa will query A again.This kind of circle loop will cause a stackOverFlow.
By the way, how about providing more info about your problem like the Exception name?It's too hard for me to give you a specific solution,All I can do is to tell you some experiences I have met before.
Well,I created a small project with SpringBoot 2.1.0 and MySql.
It's my cartItem
public class CartItem {
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Id
#Column(name="id")
private Integer id;
#JsonIgnore
#ManyToOne
#JoinColumn(name="cart_id", nullable=false)
private Cart cart;
}
and my cart:
public class Cart {
#GeneratedValue(strategy= GenerationType.IDENTITY)
#Id
#Column(name="id")
private Integer id;
#OneToMany(mappedBy="cart", fetch = FetchType.EAGER)
private List<CartItem> cartItems;
}
Controller is as same as you wrote.After adding a #JsonIgnore to cart filed of CartItem,circle loop is over(before i do that,the program did had a circle loop problem).
Every time you use jpa with #oneToMany,#ManyToOne or #ManyToMany,you should be careful about this problem.This circular reference case could happen when instantiating a object, printing a object or something like this.And of course there is a lot of way to solve it like changing fetch type to LAZY,adding #JsonIgnore,overriding toString() and equal() method.
I needed a RoleMappingService class(which is annotated by #Service) object into a Employee class (which is annotated by #Entity)
below are my classes
********************* RoleMappingsService class **********************
#Service
public class RoleMappingsService {
#Autowired
RolesMappingDao rolesMappingDao;
public List<RolesMappings> getRolesMappingByauthSystemRole(String authSystemRole) {
return rolesMappingDao.getRolesMappingByauthSystemRole(authSystemRole);
}
}
############### Employee class
#Configurable
#Component
#Entity
#NamedQuery(name = "Employee.findAll", query = "SELECT e FROM Employee e")
public class Employee implements Serializable, UserDetails {
#Autowired
#Transient
RoleMappingsService roleMappingsService;
public static final String STATUS_ACTIVE = "ACTIVE";
public static final String STATUS_INACTIVE = "INACTIVE";
public static final String STATUS_LOCKED = "LOCKED";
public static final String STATUS_ONLEAVE = "ONLEAVE";
public static final String STATUS_EXPIRED = "EXPIRED";
private static final long serialVersionUID = 1L;
#Id
#Column(name = "emp_id")
private String empId;
#Column(name = "emp_password")
private String empPassword;
#Column(name = "emp_email")
private String empEmail;
#Column(name = "emp_address")
private String empAddress;
#Column(name = "emp_age")
private int empAge;
#Column(name = "emp_firstname")
private String empFirstname;
}
Here Autowire is not working for roleMappingsService and the object is always found null. However I tried to autowire same object in some other service and there Autowire is perfectly working.
( I know Entity class is only used for representing database table but in my case I need to set some field values which depend on another table so need to fetch data using service)
JB Nizet is totally right
I'll try to provide more explanations here.
Spring can Autowire only beans, objects that it manages, and not arbitrary objects.
Entities are usually created from within a JPA (Hibernate) and are not something that you want to manage by Spring.
There is a related discussion available here but bottom line you should never do something like this.
Why not?
Here are a couple of questions/reasons:
Maybe these entities will go outside spring context at all (serialization), what should that reference contain? Should we also serialize the service? How?
What will happen if the method that turns to the service will be called "outside" the spring driven application (maybe even in different JVM)?
If there are, say 1000 objects returned by that query, do you really want all of them to reside in application context? Or maybe should they be of "prototype" scope?
As you see, it doesn't play nice with spring concepts. I think the reason for it is that Hibernate and JPA do not "support" an idea of methods inside entities, it's just a different framework. I know there are other frameworks that do allow such a concept, but Hibernate/JPA just doesn't, period
So instead of trying to inject the service into the entity bean, probably you should redesign the application so that the service method will be called from outside, maybe via some facade, and entities will be just populated by query, and then "enriched" with additional information if we're talking about SELECT queries, or, alternatively, some information should be pre-set on entity objects, generated by the Business Logic Layer and only then the entity object should be stored in DB
I cannot get why spring create the same links for self and rel? Is there a way how to disable it? I think that this only my issue because I didn't meet such problem in docs I read.
Here is my entity mapping:
#Getter
#Setter
#Document
public class Ad {
#Id
private String id;
private String description;
private Banner banner;
}
#Getter
#Setter
public class Banner {
private String id;
private String filename;
}
Here is my repository:
#RepositoryRestResource
public interface AdRepository extends CrudRepository<Ad, String> {
}
I touch the following url: http://localhost:8558/ads
I don't use any projections. My app is quite primitive now. There is nothing specific.
Thanks in advance!
My only guess is that maybe you're missing hashCode/equals and that's causing a problem
This is by design. The rel-based link allows you to see all contexts, while self link serves as the canonical link.
To further clarify, adjust your repository definition to extend not CrudRepository, but instead PagingAndSortingRepository. The two links rendered for each aggregate root will immediately look slightly different due to extended templating options.
I am using hateoas for implementing links in my repositories.So my Customer Class extends ResourceSupport which has private final List<Link> links; and in constructor
public ResourceSupport() {
this.links = new ArrayList<Link>();
}
So when I am saving customer entity using Mongo template mongoTemplate.save(customer);
So when I see the documents in Mongo db it shows
{
_id:"objectid(57vsdsjdsk),
firstName:"Yamini",
lastName:"Tyagi"
links as empty Array List(initialized in constructor)
}
So how would I avoid links to be persisted in Mongo database?
Please help on this?
I have overloaded the get method of that property in my child class and marked that as #Transient
Using the #Transient annotation that particular property will not save in Database. Hope this will help
#Override
#Transient
public java.util.List<org.springframework.hateoas.Link> getLinks() {
return super.getLinks();
}
First let me say I'm a complete novice with Spring AOP, and I apologize if this is a duplicate question.
Here's my scenario:
Let's say I have the following domain class:
#Entity(name="MyTable")
#Table(name="MY_TABLE")
public class MyTable {
private static final long serialVersionUID = 1234567890123456L;
#Id
#Column(name = "USER_ID")
private Long userID;
#Transient
private String key;
#Column(name = "KEY")
private String secureKey;
/* Other columns */
/* Getters and Setters */
}
and I have the following JPARepository class to manage it:
#Repository
public interface MyTableRepository extends JpaRepository<MyTable, Long> {
/* findBy methods */
}
As you can see, I have a secureKey field and a transient key field. In this case secureKey is an encrypted version of key.
What I need is for the secureKey value to be populated before a domain object is saved, and for the key value to be populated after a domain object is fetched. (This is a trivial example but in the real case I have multiple transient and encrypted values.) The idea is for the secure values to be persisted to the DB, but users of the domain class will only need to work with the "insecure" values.
Currently I'm handling this in my service layer. After I call a fetch method I'm populating the transient values, and before calling a save method I'm populating the "secure" values. This is working as expected but ideally I'd like this to be managed transparently, because now the burden is on each developer to remember to update those values after fetching or before saving.
I'm assuming the best way to handle this would be through some AOP class, but I confess I have little to no idea where to begin there. Is this a common scenario, and if so, would someone be willing to point me in the right direction? Also, if you have a suggestion for a better way to implement this decrypted/encrypted field pair scenario, please let me know.
Ideally I'd like to be able to add an annotation to both the secure and insecure fields, maybe pointing to each other, maybe something like:
#Insecure(secureValue = "secureKey")
#Transient
private String key;
#Secure(insecureValue = "key")
#Column(name = "KEY")
private String secureKey;
Any assistance you could provide is most appreciated.
Thanks,
B.J.
I think Spring AOP isn't the correct technology in your use case, i would recommend to use EntityListeners.
Hibernate: https://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html/listeners.html
Eclipselink: https://wiki.eclipse.org/EclipseLink/Release/2.5/JPA21#CDI_Entity_Listeners