父类和子类之间的转换

public class Person {
    private String name;
    private String doc;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDoc() {
        return doc;
    }

    public void setDoc(String doc) {
        this.doc = doc;
    }

}

public class CNPerson extends Person {

}

    @Test
    //失败
    public void test1(){        
        Person p=new Person();
        p.setName("Name");
        CNPerson cp=(CNPerson)p;
        System.out.println(cp.getName());
    }
    
    @Test
    //成功
    public void test2(){        
        CNPerson cp=new CNPerson();
        cp.setName("Name");
        Person p=(Person)cp;
        System.out.println(p.getName());
    }