constructor-injection

问题 I'm developing a Java Spring application. I have some fields in my application which are configured using a .yml config file. I would like to import those values using an @Value annotation on the fields in question. I would also like to use the best-practice of constructor injection rather than field injection, but I would like to write my constructor using Lombok rather than manually. Is there any way to do all these things at once? As an example, this doesn't work but is similar to what I

问题 This question already has answers here : Setter DI vs. Constructor DI in Spring? (8 answers) Closed 3 years ago . When to use constructor injection in Spring? I heard that constructor injection is particularly useful when you absolutely must have an instance of the dependency class before your component is used. But what does it mean? Can anybody explain me with some simple examples the following moments: What are the benefits that I will get using constructor injection ? What is dynamic

问题 I'm trying to figure out how to use Simple Injector, I've used it around the project with no problems registering simple services and their components. However, I wanted to use dependency injector when having a component with more than two constructors that implements an interface. public DAL: IDAL { private Logger logger; string _dbInstance; public DAL() { logger = new Logger(); } public DAL(string databaseInstance) { logger = new Logger(); _dbInstance = databaseInstance; } } Here is how I'm

问题 After listening to the Clean Code Talks, I came to understand that we should use factories to compose objects. So, for example, if a House has a Door and a Door has a DoorKnob , in HouseFactory we create a new DoorKnob and pass it to the constructor of Door , and then pass that new Door object to the constructor of House . But what about the class that uses the House (say the class name is ABC ) ? It will depend on the HouseFactory , right? So do we pass the HouseFactory in the constructor of

问题 Problem I regularly find myself manually typing out code that looks like this: public class SomeClass { readonly ServiceA serviceA; readonly ServiceB serviceB; public SomeClass(ServiceA serviceA, ServiceB serviceB) { this.serviceA = serviceA.; this.serviceB = serviceB; } } Requirements I would like to save time by having a way to generate as much of this as possible. I don't want to use a tool that requires a purchase. The only information that is variable here is the class name and the types

问题 I have a project that provides an interface, let's call it IImplementMe, which i want to inject into my project. This interface will be implemented by various producers, so I need to inject all implementations. I am trying to use TypeLiteral for this. Here is the code of the producer : @Singleton public class SomeImplementation implements IImplementMe { private final String value; @Inject public SomeImplementation(final SomeOtherConfig configuration) { this.value= configuration.getValue(); }

问题 I'm having a problem with Spring and constructor injection. I want to create dynamically objects with a name ( String ) and special id ( long ). But when the spring.xml file is loaded an exception occurs. Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'someBean' defined in class path resource [spring.xml]: Unsatisfied dependency expressed through constructor argument

问题 This question is probably exact duplicate of this one Pass parameter to constructor with Guice Difference is that I use roboguice for android, not just Guice, so answers there does not work for me. Question is - how can I pass initialize parameters into created object? I.e. I have injected interface which should be initialize with some parameter which roboguice does not know. What I see in link I provide, I should create factory interface and register it like this void configure(Binder binder

问题 I am trying to setup a project structure so that I have a WebApi, WebUI and Domain layer. I have moved all the Asp.Net.Identity objects into the Domain layer and have also setup the ApplicationContext here too (inheriting from IdentityContext). (I have used this tutorial and package as a base which is excellent. http://tech.trailmax.info/2014/09/aspnet-identity-and-ioc-container-registration/) In the WebAPI layer I am able to use the Account controller correctly to login and register. However

问题 I have been trying to implement Dagger2. Problem: When I use constructor injection, it works fine but when I use field injection, it throws an Error like below: Error:(6, 48) error: cannot find symbol class DaggerApplicationComponent /home/moderator/Downloads/Maulik/Sample Codes/Made/Dagger2Demo/app/src/main/java/com/dagger2demo/dagger2demo/di/component/ApplicationComponent.java Error:(18, 10) error: com.dagger2demo.dagger2demo.mvp.HomePresenter cannot be provided without an @Inject