Java中List，ArrayList用法

List是个接口，ArrayList是List接口的实现类

 

Collection
├List       接口
│├LinkedList       链表
│├ArrayList         顺序结构动态数组类
│└Vector         向量
│　└Stack       栈
└Set
Map
├Hashtable
├HashMap
└WeakHashMap List接口

 

package com.list;
import java.util.ArrayList;
import java.util.Iterator;

import com.login.User;
public class Arraylist {
	public static void main(String[] args)
	{
		//创建字符型ArrayList
		ArrayList<String> list = new ArrayList<String>();
		list.add("aa");
		list.add("bb");
		list.add("cc");
		for(int i = 0;i<list.size();i++){
			System.out.println(list.get(i));
		}
		//迭代器用于for循环遍历字符类型的list
		for (Iterator<String> iter = list.iterator(); iter.hasNext();) {
			String str = (String)iter.next();
			System.out.println(str);
		}
		//迭代器一般用while循环遍历字符类型的list
		Iterator<String> iter = list.iterator();
		while(iter.hasNext()){
			String str = (String) iter.next();
			System.out.println(str);
		}
		//创建对象型ArrayList
		ArrayList<User> userArrayList = new ArrayList<User>();
		for(int i=0;i<3;i++){
			User user = new User();
			user.setUsername("a"+i);
			user.setPassword("b"+i);
			userArrayList.add(user);
		}
		for(int i = 0;i<userArrayList.size();i++){
			System.out.println(userArrayList.get(i).getUsername()+userArrayList.get(i).getPassword());
		}
		//迭代器用于for循环遍历对象类型的list
		for (Iterator<User> iter1 = userArrayList.iterator(); iter1.hasNext();) {
			User user = iter1.next();
			System.out.println(user.getUsername()+","+user.getPassword());
		}
		//迭代器一般用while循环遍历对象类型的list
		Iterator<User> iter1 = userArrayList.iterator();
		while(iter1.hasNext()){
			User user = iter1.next();
			System.out.println(user.getUsername()+","+user.getPassword());
		}
	}
}