生成学生数组（Java）

Question

我需要生成具有这些属性的学生数组： 姓名、姓氏、专长、课程、组别。

我写了学生类并尝试创建 5 个学生

这里是代码

public class Student {
String Name;
String Surname;
String Course;
String Groupe;
String Speciality;


Student student = new Student();

public Student getStudent1() {
    student.Name = "Anastasia";
    student.Surname = "Enina";
    student.Speciality = "Programmer";
    student.Course = "4";
    student.Groupe = "1B";
    return student;
}

public Student getStudent2(){
    student.Name = "Anastasia";
    student.Surname = "Enina";
    student.Speciality = "Programmer";
    student.Course = "4";
    student.Groupe = "1B";
    return student;
}
public Student getStudent3(){
    student.Name = "Eugene";
    student.Surname = "Sukhomlyn";
    student.Speciality = "Economist";
    student.Course = "3";
    student.Groupe = "2B";
    return student;
}
public Student getStudent4(){
    student.Name = "Victor";
    student.Surname = "Sologub";
    student.Speciality = "Designer";
    student.Course = "5";
    student.Groupe = "2A";
    return student;
}
public Student getStudent5(){
    student.Name = "Serhiy";
    student.Surname = "Koshelnick";
    student.Speciality = "Audit";
    student.Course = "1";
    student.Groupe = "4C";
    return student;
}

}

主要我需要将这些学生添加到数组中

所以我尝试了这段代码

 public static void main(String[] args) {
    ArrayList<Student> mStudents = new ArrayList<>();

    mStudents.add(student);
}

但我有错误cannot resolve symbol student

我需要如何正确编写代码？

Answer 1

您将删除所有这些函数：getStudentX() - 而是编写一个构造函数，它为每个属性接受一个参数。

该构造函数将如下所示：

public Student(String name, String ...) {
    this.name = name;
    ...
}

您还删除了Student student; 行。

然后你写：

mStudent.add(new Student(arg1, arg2, ....));

创建一个新的Student 实例并添加到您的数组中。

Answer 2

您应该创建包含所有实例变量的学生类、包含所有变量的构造函数、每个变量最好的 getter 和 setter。然后，从您的主（测试类）创建 ArrayList 并包含每个学生。

ArrayList<Student> mStudents = new ArrayList<>();
mStuddents.add(new Student(Anastasia, Enina, Programmer, 4, 1B);

Answer 3

学生班级应该只是一个蓝图。当您创建多个“学生”时，您应该从 main() 中执行此操作。即，

学生 student1 = new Student();

学生 student2 = new Student();

...

学生 student5 = new Student();

然后将它们添加到您的数组中，就像现在一样，但使用实际的学生对象：

mStudents.add(student1);

mStudents.add(student2);

...

mStudents.add(student5);

您将需要重写您的 Student 课程，因为您现在拥有它并没有真正的意义。 查看此链接以供参考： https://beginnersbook.com/2013/03/constructors-in-java/

Answer 4

首先，您需要创建一个名为 Student 的类。 然后，您将向该类添加一个构造函数，以便能够实例化一个新学生。

public class Student {
 private String name;
 private String surname;
 private String course;
 private String groupe;
 private String speciality;

 public Student(String name,
               String surname,
               String course,
               String groupe,
               String speciality)
 {
     this.name = name;
     this.surname = surname;
     this.course = course;
     this.groupe = groupe;
     this.speciality = speciality;
 }

}

一旦编写了构造函数，您就可以像这样实例化一个新对象：

 Student student1 = new Student("name1", "surname1", "course1", "groupe1", "speciality1");

最后，您将能够通过这种方式创建一个学生数组列表：

//instantiation of multiple students
Student student1 = new Student("name1", "surname1", "course1", "groupe1", "speciality1");
//..
Student student5 = new Student("name5", "surname5", "course5", "groupe5", "speciality5");

// Creation of an ArrayList
ArrayList<Student> mStudents = new ArrayList();

// Adding students to the ArrayList
mStudents.add(student1);
//...
mStudents.add(student5);

希望对你有帮助！