Java学习笔记44：常用集合使用

package com.test.www;import java.util.ArrayList;import java.util.HashMap;import java.util.HashSet;import java.util.Iterator;import java.util.LinkedList;import java.util.List;import java.util.ListIterator;import java.util.Set;import java.util.SortedSet;import java.util.TreeSet;public class Test {      public static void main(String[] args) {        //链表        List<String> userList = new LinkedList<String>();        userList.add("user1");        userList.add("user2");        userList.add("user3");        userList.add("user4");        userList.add("user5");        userList.add("user6");        ListIterator<String> i = userList.listIterator();        while(i.hasNext()) {            System.out.println(i.next());        }                //ArrayList        ArrayList<String> arrayList = new ArrayList<String>();        arrayList.add("Hello World");        arrayList.add("sadoasodoasd");        arrayList.add("111111111");        System.out.println(arrayList.get(0));        System.out.println(arrayList.get(1));        System.out.println(arrayList.get(2));                //HashSet 无序        Set<String> set = new HashSet<String>();        set.add("asdasd");        set.add("asdasd1");        set.add("asdasd2");        set.add("asdasd3");        Iterator it = set.iterator();        while(it.hasNext()){         System.out.println((String)it.next());        }                //TreeSet 有序        SortedSet<String> ssetSet = new TreeSet<String>();        ssetSet.add("100");        ssetSet.add("200");        ssetSet.add("300");        for (String string : ssetSet) {            System.out.println(string);        }                //HashMap        HashMap<String, String> hashMap = new HashMap<String, String>();        hashMap.put("user0", "asdadasda");        hashMap.put("user1", "asdsad11111");        hashMap.put("user2", "11232130000");        System.out.println(hashMap.get("user0"));        System.out.println(hashMap.get("user1"));        System.out.println(hashMap.get("user2"));    }        }