Java中父类强制转换子类问题解决

class Parent {
    public void parentMethod() {
        System.out.println("Parent method");
    }
}

class Child extends Parent {
    public void childMethod() {
        System.out.println("Child method");
    }
}

Parent parent = new Child(); // 父类引用指向子类对象
Child child = new Child();   // 子类引用指向子类对象

Parent parent = new Child();
Child child = (Child) parent; // 正确的强制转换
child.childMethod();          // 调用子类方法

Parent parent = new Parent();
Child child = (Child) parent; // 抛出 ClassCastException
child.childMethod();          // 这行代码不会被执行

Parent parent = new Parent();

if (parent instanceof Child) {
    Child child = (Child) parent;
    child.childMethod();
} else {
    System.out.println("Parent is not an instance of Child");
}

List<Child> children = new ArrayList<>();
children.add(new Child());

for (Child child : children) {
    child.childMethod();
}

class Parent {
    public void method() {
        System.out.println("Parent method");
    }
}

class Child extends Parent {
    @Override
    public void method() {
        System.out.println("Child method");
    }
}

public class Main {
    public static void main(String[] args) {
        Parent parent = new Child();
        parent.method(); // 输出 "Child method"
    }
}