List容器-ArrayList

特点:

　　  有序重复,包括null,通过整数索引访问

实现类ArrayList和LinkedList

ArrayList--动态数组   不线程同步  单线程合适

        List<String> nList=new ArrayList<String>();
        nList.add("A");
        nList.add("B");
        nList.add("C");
        nList.add(1, "D");
        nList.set(2, "tanlei");
        //使用迭代器进行统一遍历
        Iterator<String> lists =nList.iterator();
        while(lists.hasNext()) {
            String name=lists.next();
            System.out.println(name);
        }
        //增强for循环遍历
        for(String name : nList) {
            System.out.println(name);
        }
        System.out.println("********");
        System.out.println(nList.indexOf("C"));//返回此元素的索引
        System.out.println(nList.remove("tanlei"));//删除首次出现的元素
        System.out.println(nList.size());//返回列表中的元素数
        System.out.println(nList.contains("tanlei"));//c查询元素中是否包含
        System.out.println(nList.get(1));//通过下标访问
        System.out.println(nList.isEmpty());//判断里面是否有内容
        nList.clear();//清空元素

 

 

package com.day1;

import java.util.ArrayList;
import java.util.List;

public class ArrayListDemo2 {
  public static void main(String[] args) {
	List<Student> stulist=new ArrayList<Student>(); 
	Student stu1=new Student("张三", 18);
	Student stu2=new Student("李四", 20);
	Student stu3=new Student("王五", 22);
	stulist.add(stu1);
	stulist.add(stu2);
	stulist.add(stu3);
	Student stu4=new Student("王五", 22);
	System.out.println(stulist.indexOf(stu4));//查找stu4王五的下标    根据自己重写的equals方法   
	System.out.println(stulist.contains(stu4));//容器包含stu4
	System.out.println(stulist.remove(stu4));//删除stu4其实是删掉了与stu4相同内容的stu3
	System.out.println(stulist.indexOf(stu3));//找不到 -1
	System.out.println(stulist.size());//大小为2
	
	
	
}
}

class  Student{
	private  String name;
	private  int age;
	
	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 boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Student other = (Student) obj;
		if (age != other.age)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}
	
	
	
}