在java.util中获取Error ArrayList不接受参数

我已经创建了一个“学生”类，现在我正在尝试将我的Student对象存储在ArrayList中，但是在编译ArrayList不接受accept参数时我遇到了错误。 我已多次检查我的代码但无法找到问题。

我的学生class就是这个

public class Student { //declaring variables private int rollNumber ; private String name ; //a counter for counting how many students or objects are declaired yet public static int studentCount = 0; public static int getStudentCount() { return studentCount; } //getters for both variables public int getRollNumber() { return rollNumber; } public String getName() { return name; } //setters for both variables public void setRollNumber(int x) { if (x > 0) { this.rollNumber = x; } else { System.out.println("Wrong Roll Number Value"); } } public void setName(String someName) { this.name = someName; } //default constructor public Student() { setName("Please Enter A Name"); this.rollNumber = 0; studentCount +=1; } //parameterized constructor public Student(String name, int x) { setName(name); setRollNumber(x); studentCount += 1; } //copy constructor public Student(Student s) { setName(s.name); setRollNumber(s.rollNumber); studentCount +=1; } //defining an print method public void print() { System.out.println("Student Name = " + name + "______Roll Number = " + rollNumber); } } 

而我所恭敬的那一课如下

 import java.util.*; public class ArrayList { public static void main (String[] anyString) { //Creating Some student objects Student s1 = new Student("Ammar" , 1); Student s2 = new Student("Ahmad" , 2); Student s3 = new Student("Arslan", 3); //Creating an arraylist ArrayList someList= new ArrayList(); //checking if our Array List is empty or not boolean empty = someList.isEmpty(); if (empty == true) System.out.println("ArrayList is Empty \n\n"); //adding our student class objects to our arraylist someList.add(s1); someList.add(s2); someList.add(s3); //checking if arraylist is empty or not empty = someList.isEmpty(); if (empty == true) System.out.println("ArrayList is Empty"); else //counting total members in a list System.out.println("Our ArrayList someList have a total of " +someList.size() + " Members \n\n"); //geting back objects from arraylist or extractin them from list //we will display our objects to console one by one for (int i = 0; i < someList.size() ; i++) { Student one = someList.get(i); one.print(); } } } 

Answer 1

清理并重命名。

 import java.util.ArrayList; public class Student { String name; int id; public Student(String name, int id) { this.name = name; this.id = id; } public static void main(String[] anyString) { // Creating Some student objects Student s1 = new Student("Ammar", 1); Student s2 = new Student("Ahmad", 2); Student s3 = new Student("Arslan", 3); // Creating an arraylist ArrayList someList = new ArrayList(); // checking if our Array List is empty or not boolean empty = someList.isEmpty(); if (empty == true) System.out.println("ArrayList is Empty \n\n"); // adding our student class objects to our arraylist someList.add(s1); someList.add(s2); someList.add(s3); // checking if arraylist is empty or not if (someList.isEmpty()) System.out.println("ArrayList is Empty"); else // counting total members in a list System.out.printf("Our ArrayList someList has a total of %d Members \n\n", someList.size()); // geting back objects from arraylist or extracting them from list // we will display our objects to console one by one for (Student student : someList) { System.out.println(student); } } @Override public String toString() { return "Student [name=" + name + ", id=" + id + "]"; } }