![](/img/trans.png)
[英]How to read file into an Arraylist and print the ArrayList in Java
[英]How to print an ArrayList? - java
問題將在下面。
public class University {
ArrayList<Student> students;
public University() {
students = new ArrayList<Student>();
}
public void addStudent(Student students) {
this.students.add(students);
}}
public class Student {
String name;
String studentID;
static int studentNumber = 0;
Student(String name, String sID){
this.name = name;
this.studentID = sID;
studentNumber++;
}}
public class TestUniversity {
public static void main(String[] args) {
University universityRegister = new University();
Student studentRegister = new Student("Rachel Green", "a1234");
universityRegister.addStudent(studentRegister);
studentRegister = new Student("Monica Geller", "a12345");
universityRegister.addStudent(studentRegister);
studentRegister = new Student("Ross Geller", "a1111");
universityRegister.addStudent(studentRegister);
System.out.println("Number of student in University: " + Student.studentNumber);
}}
A. 我在 3 個不同的文件中創建了 3 個類,1.Student、2.University、3.UniversityTester。
B. 我創建了 3 個 Studnet 類型的對象,並將它們作為 ArrayList 存儲在 University class 中。
我想知道如何打印學生的 ArrayList,包括來自 UniversityTester class 的所有信息? 將來,我將創建另一個名為 Stuff 的 object,並將其作為 ArrayList stuffList 存儲在大學 class 中。 因此,我不想從 class Student 打印學生列表。
覆蓋學生 class 中的 toString() 方法,如下所示:
import java.util.StringJoiner;
public class Student {
String name;
String studentID;
static int studentNumber = 0;
Student(String name, String sID) {
this.name = name;
this.studentID = sID;
studentNumber++;
}
@Override
public String toString() {
return new StringJoiner(", ", Student.class.getSimpleName() + "[", "]")
.add("name='" + name + "'")
.add("studentID='" + studentID + "'")
.toString();
}
}
現在您可以在 TestUniversity 中按如下方式打印數組列表:
System.out.println("Student Details: " + universityRegister.students);
將此添加到您的學生 class:
@Override
public String toString() {
return String.format("Student: %s , StudentID: %s", name, studentID);
}
然后你可以像這樣打印整個數組:
System.out.println("Students: " universityRegister.students);
//Or like this:
for(Student st: universityRegister.students){
System.out.println(st);
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.