package arraylist;import java.util.ArrayList;public class Demo1 {public static void main(String[] args) {// 创建一个空的集合对象// ArrayList<String> array = new ArrayList<>();ArrayList<String> array = new ArrayList<String>();// 添加元素// System.out.println(array.add("hello")); 返回Bool// System.out.println(array.add("dada"));array.add("haha");array.add("java");array.add("js");// 在 指定位置添加元素array.add(0,"喜");System.out.println(array);}
}
[喜, haha, java, js]
package arraylist;import java.util.ArrayList;public class demo2 {public static void main(String[] args) {ArrayList<String> array = new ArrayList<>();//在集合中添加字符串对象array.add("刘备1");array.add("刘备2");array.add("刘备3");// System.out.println(array.get(1));// size() 获取集合的长度for (int i = 0;i<array.size();i++){System.out.println(array.get(i));}}
}
package arraylist;import java.util.ArrayList;
import java.util.Scanner;public class arrayru {public static void main(String[] args) {// 创建集合对象ArrayList<Student> array = new ArrayList<Student>();/*Scanner sc = new Scanner(System.in);System.out.println("请输入学生姓名：");String name = sc.nextLine();System.out.println("请输入学生年龄：");String age = sc.nextLine();Student s = new Student();s.SetName(name);s.SetAge(Integer.parseInt(age));array.add(s);*/addStudent(array);addStudent(array);addStudent(array);for (int i=0;i<array.size();i++){Student s = array.get(i);System.out.println(s.GetName()+','+s.getAge());}}public static void addStudent(ArrayList<Student> array){Scanner sc = new Scanner(System.in);System.out.println("请输入学生姓名：");String name = sc.nextLine();System.out.println("请输入学生年龄：");String age = sc.nextLine();Student s = new Student();s.SetName(name);s.SetAge(Integer.parseInt(age));array.add(s);}}
package arraylist;import java.util.ArrayList;public class demo3 {public static void main(String[] args) {// 创建一个空的集合对象// ArrayList<String> array = new ArrayList<>();ArrayList<String> array = new ArrayList<String>();// 添加元素// System.out.println(array.add("hello")); 返回Bool// System.out.println(array.add("dada"));array.add("haha");array.add("java");array.add("js");// 删除指定的元素// System.out.println(array.remove("java")); //返回布尔值// 删除指定索引// System.out.println(array.remove(1)); // 删除并返回被删除的索引// 修改指定索引的值// System.out.println(array.set(1,"javaee")); // 修改指定索引的值，返回被修改索引的值// 返回指定索引的值// System.out.println(array.get(0));// 返回集合元素的个数System.out.println(array.size());System.out.println(array);}
}