Java 集合的嵌套

最新推荐文章于 2022-05-31 10:34:01 发布

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最新推荐文章于 2022-05-31 10:34:01 发布

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分类专栏： JavaDemo 文章标签： Java面向对象集合List Map Set

本文链接：https://blog.youkuaiyun.com/weixin_41847402/article/details/79814962

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本文通过具体实例展示了如何使用Java集合框架中的HashMap和ArrayList来管理和操作数据。包括了创建Map和List，添加元素，遍历Map和List等基本操作。

package com.neusoft.collection;

import java.security.cert.PolicyQualifierInfo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class ListMapPerson {
	public static void main(String[] args) {
		Map<String, List<Person>> map = new HashMap<>();
		List<Person> list1 = new ArrayList<>();
		Person p1 = new Person();
		p1.setSid("50");
		Person p2 = new Person();
		p2.setSid("50");
		
		list1.add(p1);
		list1.add(p2);
		
		List<Person> list2 = new ArrayList<>();
		Person p3 = new Person();
		p3.setSid("100");
		Person p4 = new Person();
		p4.setSid("100");
		
		list2.add(p3);
		list2.add(p4);
		
		map.put("1", list1);
		map.put("2", list2);
		
		Set<Entry<String, List<Person>>> set = map.entrySet();
		Iterator<Entry<String, List<Person>>> iterator = set.iterator();
		while (iterator.hasNext()) {
			Entry<String, List<Person>> entry = iterator.next();
			List<Person> list = entry.getValue();
			
			for (int i = 0; i < list1.size(); i++) {
				System.out.println(list1.get(i).getSid());
			}
	或
			for (Person person : list) {
				System.out.println(person.getSid());
			}
		}
		
		
		
		List<Map<String, Person>> list = new ArrayList<>();
		Map<String, Person> maps1= new HashMap<>(); 
		Person p1 = new Person();
		p1.setSid("100");
		p1.setSname("tom");
		p1.setAge(30);
		Person p2 = new Person();
		p2.setSid("101");
		p2.setSname("tom2");
		p2.setAge(32);
		Person p3 = new Person();
		p3.setSid("102");
		p3.setSname("tom3");
		p3.setAge(33);
		maps1.put("1", p1);
		maps1.put("2", p2);
		maps1.put("3", p3);
		
		Map<String, Person> maps2= new HashMap<>(); 
		Person p4 = new Person();
		p4.setSid("103");
		p4.setSname("tom4");
		p4.setAge(35);
		Person p5 = new Person();
		p5.setSid("104");
		p5.setSname("tom5");
		p5.setAge(36);
		Person p6 = new Person();
		p6.setSid("105");
		p6.setSname("tom6");
		p6.setAge(37);
		maps1.put("1", p4);
		maps1.put("2", p5);
		maps1.put("3", p6);
		
		list.add(maps1);
		list.add(maps2);
		
		for (int i = 0; i < list.size(); i++) {
			Map<String, Person> map = list.get(i);
			Set<Entry<String, Person>> set = map.entrySet();
			Iterator<Entry<String, Person>> iterator = set.iterator();
			while(iterator.hasNext()){
				Entry<String, Person> entry = iterator.next();
				Person person = entry.getValue();
				System.out.println(person.getSid()+"---"+person.getSname()+"---"+person.getAge());
			}
		}

}
	}
	
}