打印覆盖到字符串()方法

Question

我有两个不同的类，学生和学生测试 - 学生类有;

public class Student {
// Data Members 
private String name; // The name of this student
private long idNumber; // The ID number of this student
// Constructs a new Student with passed name and ID number parameters.
public Student(String studentName, long studentIDNumber) {
name = studentName;
idNumber = studentIDNumber;
}
// Returns the name of this student.
public String getName() {
return name;
}
// Returns the ID number of this student.
public long getIDNumber() {
return idNumber;
}
// Sets the name of this student.
public void setName(String studentName) {
name = studentName;
}
// Sets the ID number of this student.
public void setIDNumber(long studentIDNumber) {
idNumber = studentIDNumber;
}
@Override
public String toString(){
    return "Name: " + this.name;
}
} // end class

StudentTest 类有 3 种不同的方法，1. 要求用户输入数组的大小，然后创建 Student 类型的数组，2. 要求用户使用名称和 ID 号填充数组，3. 显示数组的内容。

import java.util.Scanner; 
public class StudentTest { 
// Main method.
public static void main(String [] args) {
    Student[] students = createArray();
    populateArray(students);
    displayArray(students);
}
// Method that asks user for size of array.
public static Student[] createArray() {
System.out.println("Enter size of array: ");
Scanner userInputEntry = new Scanner(System.in);
int inputLength = userInputEntry.nextInt();
Student students[] = new Student[inputLength];
return students; 
}
// Method that asks user to populate array.
public static void populateArray(Student [] array) {
    for(int i = 0; i < array.length; i++) {
        array[i] = new Student();
        System.out.println("Enter student name: ");
        Scanner userInputEntry = new Scanner(System.in);
        array[i].setName(userInputEntry.next());
        System.out.println("Enter student ID number: ");
        array[i].setIDNumber(userInputEntry.nextLong());
    }
}
// Method that displays contents of array.
public static void displayArray(Student[] array) {
    for(int i = 0; i < array.length; i++){
        System.out.println(array[i].toString());
    }
}
}

当我尝试运行它时，我收到有关

 array[i] = new Student();

在第二种方法的 for 循环中。

Answer 1

你期望它如何工作？

@Override
public void toString(){
    return "Name: " + this.name;
}

它应该给你一个编译错误。您正在尝试发回字符串，但返回类型为 void。

将其更改为

@Override
public String toString(){
    return "Name: " + this.name;
}

将主方法更改为

// Main method.
public static void main(String [] args) {
    Student[] students = createArray();
    populateArray(students);
    displayArray(students)
}