Java中List，ArrayList用法

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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ArrayListArrayList<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listfor (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listIterator<String> iter = list.iterator();while(iter.hasNext()){String str = (String) iter.next();System.out.println(str);}//创建对象型ArrayListArrayList<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listfor (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listIterator<User> iter1 = userArrayList.iterator();while(iter1.hasNext()){User user = iter1.next();System.out.println(user.getUsername()+","+user.getPassword());}}}

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