无法打印我的数组对象

Question

我正在尝试编写一个应用程序，该程序需要用户指定的数字，然后使这些许多对象（我称它们为学生）为它们分配随机名称和数字，然后对它们的数字进行排序。我有种解决方法，但是在打印数组时遇到问题。我的代码如下。我得到的输出是“New Object”输入的次数，后面跟着每个toString调用的“0：null”。任何帮助将不胜感激。谢谢。

import java.util.Random; 
import java.util.Scanner; 

public class application { 

public static void main(String[] args) { 

    int studentSerialNumber; 
    String studentName; 

    System.out.println("Enter the number of students you would like to sort: "); 
    Scanner scanner = new Scanner(System.in); 
    int numOfStudents = scanner.nextInt(); 

    Student[] anArrayToSort = new Student[numOfStudents]; 

    for (int i = 0; i < anArrayToSort.length; i++) { 

     studentSerialNumber = ((int)(Math.random() * 8888)) + 1000; 
     studentName = getStudentName(); 

     anArrayToSort[i] = new Student(studentSerialNumber, studentName); 

    } 

    for (int i = 0; i < anArrayToSort.length; i++) { 
     System.out.println(anArrayToSort[i].toString()); 

    } 
} 

private static String getStudentName() { 

    String studentName = ""; 
    int i = 7; 
    Random r = new Random(); 

    while (i > 0) { 
     char c = (char) (r.nextInt(26) + 'a'); 
     studentName = studentName + c; 
     i--; 
    } 

    return studentName; 
} 
} 


public class Student { 

int studentSerialNumber; 
String studentName; 

Student(int studentSerialNumber, String studentName) { 

    studentSerialNumber = studentSerialNumber; 
    studentName = studentName; 
    System.out.println("New Object"); 

} 

public String toString() { 
     return studentSerialNumber + ": " + studentName; 
    } 
} 

Answer 1

分配在构造函数中有坏：

Student(int studentSerialNumber, String studentName) { 
    studentSerialNumber = studentSerialNumber; 
    studentName = studentName; 
    System.out.println("New Object"); 
} 

这应该是：

Student(int studentSerialNumber, String studentName) { 
    this.studentSerialNumber = studentSerialNumber; 
    this.studentName = studentName; 
    System.out.println("New Object"); 
} 

---

目前您是分配值本身，而不是对Student实例字段。