Java-ArrayList应用

存储随机数字

ArrayListRandom.java

package cn.day04;

import java.util.ArrayList;
import java.util.Random;

public class ArrayListRandom {
    public static void main(String[] args) {
        ArrayList<Integer> list = new ArrayList<>();
        for (int i = 0; i < 6; i++) {
            list.add(new Random().nextInt(33) + 1);
            System.out.println(list);
        }
       /* for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }*/
        for (Integer integer : list) System.out.println(integer);
    }
}

Running result

[23]
[23, 27]
[23, 27, 13]
[23, 27, 13, 33]
[23, 27, 13, 33, 26]
[23, 27, 13, 33, 26, 23]
23
27
13
33
26
23

存储自定义对象

Student.java

package cn.day04;

public class Student {
    private String name;
    private int age;

    public Student() {
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

ArrayListStudent.java

package cn.day04;

import java.util.ArrayList;

public class ArrayListStudent {
    public static void main(String[] args) {
        ArrayList<Student> list = new ArrayList<>();

        Student one = new Student("大明", 20);
        Student two = new Student("二明", 21);
        Student three = new Student("小舞", 31);

        list.add(one);
        list.add(two);
        list.add(three);

        for (int i = 0; i < list.size(); i++) {
            Student stu = list.get(i);
            System.out.println("姓名：" + stu.getName() + "  年龄:" + stu.getAge());
        }
        System.out.println("===========================");

        for (Student student : list) {
            String s = "姓名：" + student.getName() + "  年龄：" + student.getAge();
            System.out.println(s);
        }

    }
}

Running result

姓名：大明  年龄:20
姓名：二明  年龄:21
姓名：小舞  年龄:31
===========================
姓名：大明  年龄：20
姓名：二明  年龄：21
姓名：小舞  年龄：31