JAVA基础 - Collection集合存储自定义类型的对象

一、Movies.java

package com.java.base;

/*
需求：某影院系统需要在后台存储上述三部电影，然后依次展示出来
分析：
1、定义一个电影类，定义一个集合存储电影对象
2、创建3个电影对象，封装相关数据，把3个对象存入到集合中去
3、遍历集合中的3个对象，输出相关信息
 */

public class Movies {
    private String name;
    private double score;
    private String actor;

    public Movies() {
    }

    public Movies(String name, double score, String actor) {
        this.name = name;
        this.score = score;
        this.actor = actor;
    }

    public String getName() {
        return name;
    }

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

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }

    public String getActor() {
        return actor;
    }

    public void setActor(String actor) {
        this.actor = actor;
    }

    @Override
    public String toString() {
        return "Movies{" +
                "name='" + name + '\'' +
                ", score=" + score +
                ", actor='" + actor + '\'' +
                '}';
    }
}

二、MoviesTest.java

package com.java.base;

import java.util.ArrayList;
import java.util.Collection;

public class MoviesTest {
    public static void main(String[] args) {
        Collection<Movies> movies = new ArrayList<>();
        movies.add(new Movies("<你好>",9.5,"沈腾"));
        movies.add(new Movies("<刺杀>",9.1,"王宝强"));

        for (Movies mo : movies){
            System.out.println(mo);//这种写法输出的是集合的地址com.java.base.Movies@685f4c2e，
　　　　　　　　当Movies类重写了toString方法后，输出的是Movies{name='<你好>', score=9.5, actor='沈腾'}
            //可以通过get方法获取集合信息
            System.out.println("片名："+mo.getName());
            System.out.println("得分："+mo.getScore());
            System.out.println("主演："+mo.getActor());
        }
    }
}

三、输出结果

 四、list集合的遍历方式

package com.java.base;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

public class MoviesTest {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("张三丰");
        list.add("李白");
        list.add("java");

        //在某个索引位置插入元素
        list.add(2,"html");
        System.out.println(list);

        //根据索引删除元素，返回被删除元素
        list.remove(2);
        System.out.println(list);

        //根据索引获取元素，get返回集合中指定位置的元素
        System.out.println(list.get(2));

        //修改索引位置处的元素，set
        System.out.println(list.set(1,"张无忌"));
        System.out.println(list);

        //for循环
        for(int i = 0;i<list.size();i++){
            String ele = list.get(i);
            System.out.println(ele);
        }

        //迭代器
        Iterator<String> iterator = list.iterator();
        while (iterator.hasNext()){
            String ele = iterator.next();
            System.out.println(ele);
        }

        //foreach
        for(String ele : list){
            System.out.println(ele);
        }

        //lambda表达式
        list.forEach(s -> {
            System.out.println(s);
        });

    }
}