dependency-injection

问题 why am i able to see First Constructor even if i specified the type can anyone please explain me what is happening behind the scene... since i don't want to specify the index positions i need to call second constructor based on the type. public class Employee { String name; int id; public Employee(String name,int id) { System.out.println("First Constrcuot "); } public Employee(int id,String name){ System.out.println("Second Constrcuot "); } } I have My Beans.xml as follows: <bean id="employee

问题 why am i able to see First Constructor even if i specified the type can anyone please explain me what is happening behind the scene... since i don't want to specify the index positions i need to call second constructor based on the type. public class Employee { String name; int id; public Employee(String name,int id) { System.out.println("First Constrcuot "); } public Employee(int id,String name){ System.out.println("Second Constrcuot "); } } I have My Beans.xml as follows: <bean id="employee

问题 How can I set a default value to a property, reading it from my appsettings.json file, on a model that is instantiated by the .NET Core 3 framework? I've created a repo (a completely new .NET Core 3 project) where I try to illustrate the problem: https://github.com/NelsonPRSousa/dependency-injection-default-constructor API Action: [HttpGet] public IEnumerable<WeatherForecast> Get([FromQuery] FilteringRequestModel request) { var defaultType = request.Type; var rng = new Random(); return

问题 Yesterday I pushed my new Vaadin 13 Spring application to my server. When I then opened my app in the browser, the login and the dashboard view worked fine, but whenever I tried to navigate to a View that has a constructor with injected dependencies, it threw a NullPointerException. This never happens to me when I run the app locally! I am at a total loss here and have no idea how to fix this. I have tried all possible variations how to annotate the injections for the view constructor. They

问题 Can I get Spring to throw an exception when there is more than one bean with the same type? The current behavior seems to be to inject null . 回答1: You need to use the @Qualifier annotation together with @Annotated to resolve ambiguity between different beans with the same type. The parameter to Qualified is the name of the bean, which is automatically set based on the name of the method that is annotated with @Bean . @Autowired public RobotController (@Qualifier("gundam") RobotEngine

问题 Service Registration services.AddScoped(typeof(PageStorageService<>), typeof(PageStorageService<>)); Service Declaration public interface IStoredPage<T> { T PageState { get; set; } } public class PageStorageService<T> : IStoredPage<T> { public T PageState { get; set; } } Usage in CounterPage @page "/counter" @using BlazorApp1.Data <h1>Counter</h1> <p>Current count: @currentCount</p> @inject PageStorageService<Counter> StorageService <button class="btn btn-primary" @onclick="IncrementCount"

问题 Why is the subcomponents = attribute set on a module of a component and not on the component directly? This doesn't seem very intuitive to me so I guess there must be a reason. @Component(modules = ExampleModule.class) public interface AppComponent @Module(subcomponents = ActivityComponent.class) public abstract class ExampleModule 回答1: In a sense, it makes more sense for subcomponents to be on modules: They're private implementation details that are not necessarily exposed publicly, and ones

问题 I am using apollo graphql, and it has a module with a function inside of it. export function createApollo(httpLink: HttpLink, connectToDevTools: true){ Inside this function you define the url for the graphql endpoint const uri = http://127.0.0.1/graphql for instance. I would like to import this url form a service (so that I only have to change the backend server url in one place), but I can not inject the service, for the property stays undefined. export function createApollo(httpLink:

问题 I'm trying to register a collection along with its instanceCreator. I wasn't able to find any overload for the Container.Collection.Register method which accepts an instanceCreator. If i try to run a loop and register a type along with its instanceCreator multiple times using the Container.Register(instanceCreator, lifestyle) , i'm unable to do it because i get the error that type cannot be registerd multiple times. Basically what i'm trying to do is: foreach(var item in items){ Container

问题 I am learning DI and new to spring while trying out CI I have written following code and I think I am correct in syntax still it's showing bean creation error. why it is unable to create bean..?? The code is Constuctor.java package beans; public class Constructor { private String name; private int age; private String email; public void Constructor(String name, int age, String email){ this.name=name; this.age=age; this.email=email; } public void show() { System.out.println("Name = "+name);