I am using Spring-JDBC with Tapestry and not able to inject DAO bean which I have defined in Spring.xml. Normally we use applicationContext.getBean, but in tapestry I am not able to find such option. Please guide me how I can inject DAO bean to use it in my code. Below is kind of code I am having:
Class ABC{
with private members, getters,setters and constructors
}
Class abcDAO{
private JdbcTemplate template
//getter and setter for jdbc template
//a method which will extract data using Rowmapper
public Set<ABC> getAll(){
//override mapRow method
}
}
I want to use getAll method in a class which will process extracted data. Please help me where should I inject abcDAO bean with below line:
#Inject private abcDAO abcDao;
Thanks in advance!!!
Related
I'm working on a spring project from our customer.
Below is the code for controller
#Log4j2
#RestController
#AllArgsConstructor
#RequestMapping(path = "/api/theapi")
#Api(value = "Description for the API")
public class TheAPIController {
private final ModelMapper modelMapper;
private final ObjectMapper objectMapper;
private final TheDemoService demoService;
...other code for controller
}
Below is the code for Service:
#Service
public class TheDemoService{ ... }
I was so surprise about 2 things:
Question 1: Why we need to use #AllArgsConstructor from project Lombok?
As per my understanding, Spring provide #RestController that Spring runtime container will initialize an Instance for our Controller. So that, having a constructor for our Controller seems like an invalid approach for using Spring Inversion of Control, is this correct?
Question 2. Because of using #AllArgsConstructor, somehow, the instance for demoService is to be injected
But again, I surprise because the code of Controller does not have #Autowired in combine with demoService.
In the actual code, there is no #Autowired for "private final TheDemoService demoService".
Hence, I could think of a possibility there, is that because of Lombok's #AllArgsConstructor would inject an instance of our TheDemoService via a constructor of
TheAPIController, I could not reason anything about this logic.
It's Invalid approach, no need for defining constructor for RestController
It's implicitly auto wiring the service
if a class, which is configured as a Spring bean, has only one constructor, the Autowired annotation can be omitted and Spring will use that constructor and inject all necessary dependencies.
To sum up #AllArgsConstructor can/should be removed
A GenericServlet is a type of ServletConfig, also GenericServlet has a ServletConfig. What is logic in this? How should I understand this?
public abstract class GenericServlet implements Servlet, ServletConfig, Serializable {
private static final long serialVersionUID = 1L;
private transient ServletConfig config;
..
}
The ServletConfig is an interface and is implemented by services in order to pass configuration information to a servlet when it is first loaded.
GenericServlet implements ServletConfig. It's not a subclass of ServletConfig. Understand the difference between a subclass and interface.
GenericServlet class implements Servlet, ServletConfig and Serializable interfaces. It provides the implementation of all the methods of these interfaces except the service method.
GenericServlet class can handle any type of request so it is protocol-independent.
You may create a generic servlet by inheriting the GenericServlet class and providing the implementation of the service method.
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How can i get the pojo class object say Employee in controller class using spring 4 annotation and which annotation is used to get the form parameter in controller class?
I am new in spring and just started to learn.
Please suggest the best site/tutorial to learn spring so that i can have handson on it.
Thanks in Advance
If I clearly understood your question, pass the object to the Controller using the #ModelAttribute annotation:
public class Controller {
#ModelAttribute("employee")
public Employee getEmployeel() {
return new Employee();
}
#RequestMapping ("/index")
public void index(#ModelAttribute ("employee") Employee employee, Model model) {
//some logic
}
}
To get the object from the Spring form, use #ModelAttribute too.
You can try the well-rated "Spring in Action" book. Also, if you feel comfortable with video lessons, you could try Gontuseries.
I have a stateful session bean where a list is maintained:
#Stateful
public class CartDAO{
private List<ShoppingCart> tempCart;
public void add(ShoppingCart shoppingCart){
tempCart.add(shoppingCart);
}
public List<ShoppingCart> getCart(){
return tempCart;
}
#PostConstruct
public void init(){
tempCart = new ArrayList<>();
}
}
Controller1 to add to the cart:
#Named
#SessionScoped
public class Controller1 implements Serializable {
#EJB
CartDAO cartDao;
public String addToShoppingCart() {
cartDao.add(shoppingCart);
}
}
Now, i want to ask you could i get the added items to the list from another cart?
#Named
#SessionScoped
public class Controller2 implements Serializable {
#EJB
CartDAO cartDao;
public String getShoppingCart() {
System.out.println(cartDao.getCart());//returns null
}
}
Obviously the above code returns null.
How do I retrieve the list from another controller. Any help will be much appreciated.
I don't see any obvious mistake here (are you sure that you don't call Controller2#getShoppingCart() before adding any items do your CartDAO?) but here are couple of my notions
you should have your CartDAO implement some interface or make it #LocalBean
all stateful beans should have method annotated with #Remove so you can clean the resources used in the bean (close datasources and son) and bean will be removed from the memory after this call
now it's recommended to use #Inject everywhere instead of #EJB, it's the same (you have to use #EJB only when you inject remote beans)
And also one point, if the System.out.println(cartDao.getCart()); returns null than it means the #PostConstruct haven't been called which is strange. Can you provide some more info about container and your environment?Also show us imports, this is big source of mistakes.
I have a Spring portlet controller class. In this class, there is a dependency like this:
#Autowired
protected ServiceClass someService;
#Autowired
protected ApplicationContext context;
From the controller, there is a utility class being called like this:
UtilityClass.loadStaticData((WebApplicationContext)context);
Inside UtilityClass, I have:
public static synchronized boolean loadStaticData(WebApplicationContext context){
ServiceClass someService = (ServiceClass) context.getBean("someService");
...
}
My question is: Is there any advantage to getting the handle of the someService in such a complicated way? We could have just passed the reference 'someService' from Controller class #1 to the UtilityClass. The author is no longer available so I am asking here.
This is basically what dependency injection tries to avoid: getting a dependency from the container instead of having the dependency injected by the container.
This utility class should be a Spring bean, where the service would be injected. And you could then inject this utility bean inside the controller.