Java:创建其构造函数可能引发异常的静态类成员

Question

我有一个用于设置 MyClass 的所有实例的静态 setter :

public class MyClass {  
        ....
    protected static final Setter setter = new Setter();
        ...
}

然而，由于 setter 构造函数抛出异常，因此无法编译:

public class Setter {

    public Setter() throws FileNotFoundException {
             ....
    }
}

我该如何解决这个问题？

Answer 1

ExceptionInInitializerError正是为此目的而设计的。这是链接的 Javadoc 中的相关引用:

Signals that an unexpected exception has occurred in a static initializer. An ExceptionInInitializerError is thrown to indicate that an exception occurred during evaluation of a static initializer or the initializer for a static variable.

将赋值包装在静态初始化 block 中并进行相应处理。

public class MyClass {  
    protected static final Setter setter;

    static {
        try { 
            setter = new Setter();
        } catch (FileNotFoundException e) {
            throw new ExceptionInInitializerError(e);
        }
    }
}