Java，导入未解析，继承，内部类

Question

最近在求java编程，遇到错误。请帮忙

有两个类，PersonTest.java：

 public class PersonTest {

  public static void main(String[] args) {
    Person person1=new Person("dummy","sdymmt","20","male","washington");
    System.out.println("Name: "+person1.getName());
    System.out.println("Surname: "+person1.getSurname());
    System.out.println("Age: "+person1.getAge());
    System.out.println("Gender:" +person1.getGender());
    System.out.println("Birthplace: "+person1.getBirthplace());
    Person person2= new Person(400);
    System.out.println("Income:"+person2.getX()+" mije leke");
    System.out.println("Tax:"+person2.Taksat()+" mije leke");
    Student student1= new Student("adsd","zedsdsadza");
    System.out.println("emri"+student1.getEmer());
}

}

还有 Person.java ：

public class Person {
    private String Name;
    private String Surname;
    private String Age;
    private String Gender;
    private String Birthplace;
    private double x;
    public Person()
    {

    }
    public Person(String Name, String Surname, String Age, String Gender, String Birthplace) {
        this.Name = Name;
        this.Surname = Surname;    
        this.Age = Age; 
        this.Gender = Gender;
        this.Birthplace = Birthplace;

    }

    public String getName() {
        return Name;
    }

    public String getSurname() {
        return Surname;
    }

    public String getAge() {
        return Age;
    }

    public String getGender() {
        return Gender;
    }

    public String getBirthplace() {
        return Birthplace;
    }

    public Person(double x) {
        this.x = x;
    }

    public double getX() {
        return x;
    }

    double Taksat() {
        return (0.1 * x);
    }

    public class Student extends Person {
        private String University;
        private String Faculty;

        public Student(String Universiteti, String Fakulteti) {
            super(Name, Surname, Age, Gender, Birthplace);
            this.Faculty = Fakulteti;
            this.University = Universiteti;
        }

        public String getFaculty() {
            return Faculty;
        }

        public String getUniversity() {
            return University;
        }
    }
}

两个类在同一个默认包中。如何解决测试班不将内班学生识别为班级的事实。

Answer 1

嵌套的非静态类称为Inner Classes，如果没有Outer class（包装它们），这些类就无法生存。

Java docs

InnerClass 的实例只能存在于 OuterClass 并可以直接访问其方法和字段 封闭实例。

要实例化一个内部类，必须先实例化外部类 班级。然后，用这个在外部对象中创建内部对象 语法：

OuterClass.InnerClass innerObject = outerObject.new InnerClass();

尝试使用：

Person.Student student = person1.new Student(PARAMETERS);

重要标记：

当然，您应该高度考虑这不是一个好的设计，因为您可能希望这些类在 Person class 之外可见，而且还因为 Person.Student 继承自 Person，它已经包含Student class，通常看起来像一个循环或圆形关系，这通常不是一个好主意。

Answer 2

因为没有 Student 类。既然是嵌套的，就是Person.Student