java 协变数组类型

java 协变数组类型

主要表现编译期没错，运行期间抛出java.lang.ArrayStoreException

代码实例：
父类

public class Persion {

    private String name;
    private Integer age;
    
    public Persion(String name,Integer age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Persion [name=" + name + ", age=" + age + "]";
    }
    
    
}

子类 Emp

public class Emp extends Persion{

    public Emp(String name, Integer age) {
        super(name, age);
    }

}

子类 Status

public class Status extends Persion{
    
    private String address;

    public Status(String name, Integer age) {
        super(name, age);
        this.address = "武当山上";
    }

    @Override
    public String toString() {
        return super.toString() + "Status [address=" + address + "]";
    }
}

测试

		Persion[] p = new Status[3];
        p[0] = new Persion("zhangsan",30);
        p[1] = new Status("李四",40);
        p[2] = new Emp("王五",50);
        
        System.out.println(p[0]);
        System.out.println(p[1]);
        System.out.println(p[2]);

结果

java.lang.ArrayStoreException: Persion

再次测试

 	Persion[] p = new Status[3];
    //p[0] = new Persion("zhangsan",30);
    p[1] = new Status("李四",40);
    // p[2] = new Emp("王五",50);
    
     //System.out.println(p[0]);
    System.out.println(p[1]);
    // System.out.println(p[2]);

结果

Persion [name=李四, age=40]Status [address=武当山上]