如何在 Java 中实现自定义可迭代对象?
javaobject oriented programmingprogramming更新于 2025/6/8 22:36:17
Iterable 接口在 java.lang 包 中定义，并随 Java 5 版本 一起引入。实现此接口的对象允许它成为"for-each"语句的目标。此 for-each 循环用于迭代数组和集合。还可以实现 Iterable 接口来创建自定义行为。
语法
public interface Iterable<T>
示例
import static java.lang.String.format;
import java.util.*;
// Person class
class Person {
private String firstName, lastName;
private int age;
public Person(){ }
public Person(String firstName, String lastName, int age) {
this.firstName = firstName;
this.lastName = lastName;
this.age = age;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public int getAge() {
return age;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return format("First Name:\t%s\tLast Name:\t%s\tAge:\t%d", firstName, lastName, age);
}
}
// PersonArrayList class
public class PersonArrayList implements Iterable<Person> {
private List<Person> persons;
private static final int MIN_AGE = 10;
public PersonArrayList() {
persons = new ArrayList<Person>(MIN_AGE);
}
public PersonArrayList(int age) {
persons = new ArrayList<Person>(age);
}
public void addPerson(Person p) {
persons.add(p);
}
public void removePerson(Person p) {
persons.remove(p);
}
public int age() {
return persons.size();
}
@Override
public Iterator<Person> iterator() {
return persons.iterator();
}
public static void main(String[] args) {
Person p1 = new Person("Adithya", "Sai", 20);
Person p2 = new Person("Jai","Dev", 30);
PersonArrayList pList = new PersonArrayList();
pList.addPerson(p1);
pList.addPerson(p2);
for (Person person : pList) {
System.out.println(person);
}
}
}
输出
First Name: Adithya Last Name: Sai Age: 20 First Name: Jai Last Name: Dev Age: 30
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