List实现类----ArrayList的使用

import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;

public  class Demo01 {
    public static void main(String[] args) {
        //ArrayList的使用
        //存储结构：数组，查询快，增删慢；运行效率快，线程不安全

        /*
        ArrayList源码分析
        DEFAULT_CAPACITY=10 默认容量
        注意：如果没有向集合中添加任何元素时，容量为0，添加一个元素后，容量为10；容量超过10后，容量会扩容，每次扩容大小时原来的1.5倍
        elemenData 存放元素的数组
        size 实际的元素个数
        add(); 添加元素
         */

        //创建集合
        ArrayList arrayList = new ArrayList<>();

        //1.添加元素
        Student s1 = new Student("张三", 16);
        Student s2 = new Student("李四", 16);
        Student s3 = new Student("王五", 16);
        arrayList.add(s1);
        arrayList.add(s2);
        arrayList.add(s3);
        System.out.println("元素个数："+arrayList.size());//元素个数：3
        System.out.println(arrayList);//[Student{name='张三', age=16}, Student{name='李四', age=16}, Student{name='王五', age=16}]

        //2.删除元素
        //arrayList.remove(0);
        //arrayList.remove(s1);
        arrayList.remove(new Student("张三", 16));
        System.out.println("元素个数："+arrayList.size());//元素个数：2
        System.out.println(arrayList);//[Student{name='李四', age=16}, Student{name='王五', age=16}]

        //3.遍历元素
          //1.使用迭代器
        Iterator iterator = arrayList.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }

          //2.列表迭代器
        ListIterator listIterator = arrayList.listIterator();
        //从前往后
        while (listIterator.hasNext()){
            System.out.println(listIterator.next());
        }
        //从后往前
        while (listIterator.hasPrevious()){
            System.out.println(listIterator.previous());
        }

        //4.判断
        System.out.println(arrayList.contains(new Student("彭于晏",24)));//false
        System.out.println(arrayList.contains(new Student("李四",16)));//true
        System.out.println(arrayList.isEmpty());//false

        //5.查找
        System.out.println(arrayList.indexOf(s3));//1
    }
}

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;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    @Override
    public boolean equals(Object obj) {
        //1.判断是否为空
        if(obj==null){
            return false;
        }
        //2.判断是否为同一个对象
        if(obj==this){
            return  true;
        }
        //判断是否可转为Student类型
        if(obj instanceof Student){
            Student s=(Student) obj;//强转
            if(this.name.equals(s.getName())&&this.age==s.getAge()){
                return true;
            }
        }
        return false;
    }
}