可以将@ManagedPropery和@PostConstruct放在基类中吗? [英] Can @ManagedPropery and @PostConstruct be placed in a base class?

问题描述

我正在使用类的层次结构，而我最想尝试做的是让@ManagedBean继承具有@ManagedProperty成员和@PostConstruct方法的类.

I'm using a hierarchy of classes and what I would optimally try to do is have @ManagedBean's that inherit a class that have @ManagedProperty members and @PostConstruct methods.

具体来说，这行得通吗? :

Specifically, will this work? :

public class A {

    @ManagedProperty
    private C c;

    @PostConstruct
    public void init() {
        // Do some initialization stuff
    }

    public C getC() {
        return c;
    }

    public void setC(C c) {
        this.c = c;
    }
}

@ManagedBean
@SessionScoped
public class B extends A {
    // Content...
}

预先感谢！

推荐答案

@ManagedProperty是继承的，将以这种方式工作.如果子类本身没有@PostConstruct方法，则@PostConstruct也将被继承.即只能有一个.因此，如果子类本身具有@PostConstruct，则不会调用超类的"@PostConstruct".

The @ManagedProperty is inherited and will just work that way. The @PostConstruct will also be inherited, provided that the subclass itself doesn't have a @PostConstruct method. There can namely be only one. So if the subclass itself has a @PostConstruct, then the superclass' one won't be invoked.

因此，如果您在子类中覆盖@PostConstruct，则需要显式调用超类的那个.

So if you override the @PostConstruct in the subclass, then you'd need to explicitly invoke the superclass' one.

public class SuperBean {

    @PostConstruct
    public void init() {
        // ...
    }

}

@ManagedBean
public class SubBean extends SuperBean {

    @PostConstruct
    public void init() {
        super.init();
        // ...
    }

}

或者，提供子类必须实现的抽象方法(没有@PostConstruct！).

Alternatively, provide an abstract method which the subclass must implement (without @PostConstruct!).

public class SuperBean {

    @PostConstruct
    public void superInit() {
        // ...
        init();
    }

    public abstract void init();

}

@ManagedBean
public class SubBean extends SuperBean {

    @Override
    public void init() {
        // ...
    }

}

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