public class ClassCastTest {

public static void main(String[] args) {

FiClass fiClass=new FiClass();

BaseClass baseClass=new BaseClass();

BaseClass baseFi=new FiClass();//向上转型不需要强转

BaseClass f2=(BaseClass)new FiClass();

// FiClass fiBase=(FiClass) new BaseClass();//会有异常，因为父类不能直接强转为子类

FiClass ff=(FiClass) baseFi;//没有异常，因为当该引用类型的引用是父类但是对象是子类（已经经过向上转型）,可以进行强转

System.out.println(fiClass instanceof FiClass);

System.out.println(baseClass instanceof BaseClass);

System.out.println(baseClass instanceof FiClass);

System.out.println(fiClass instanceof BaseClass);

System.out.println(ff instanceof BaseClass);

System.out.println(ff instanceof FiClass);

}

}

class BaseClass{

private int num;

public void setNum(int num) {

this.num = num;

}

public int getNum() {

return num;

}

}

class FiClass extends BaseClass{

private String f;

public void setF(String f) {

this.f = f;

}

public String getF() {

return f;

}

}