Java的ArrayList，HashSet,HashMap 遍

package cn.sxt.mycollection;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;


import java.util.Set;

public class TestIterator {
    public static void main(String[] args){
        TestIteratorList();
        TestIteratorSet();
        TestIteratorMap();
    }
    
    public static void  TestIteratorList(){
        List<String> list = new ArrayList<>();
        list.add("aa");
        list.add("bb");
        list.add("cc");
        //for遍历ArrayList
        for(String i:list){
            System.out.println("1--"+i);
        }
        
        for(int i=0;i<list.size();i++){
            System.out.println("2--"+list.get(i));
        }
        
        //使用iterator迭代器遍历list
        for(Iterator<String> iter = list.iterator();iter.hasNext();){
            String temp = iter.next();   
            System.out.println(temp);
        }
        
        
        // 获取迭代器
        Iterator<String> it = list.iterator();
        // 输出集合中的所有元素
        while(it.hasNext()) {
            System.out.println("while"+"--"+it.next());
        }
    }
    
    
    
    public static void  TestIteratorSet(){
        Set<String> set = new HashSet<>();//Set/HashSet
        set.add("aa");
        set.add("bb");
        set.add("cc");
        
        for(String i:set){
            System.out.println("1--"+i);
        }
        
        //使用iterator迭代器遍历list
        for(Iterator<String> iter = set.iterator();iter.hasNext();){
            String temp = iter.next();  
            System.out.println(temp);
        }
        
        // 获取迭代器
        Iterator<String> it = set.iterator();
        // 输出集合中的所有元素
        while(it.hasNext()) {
            System.out.println("while"+"--"+it.next());
        }
        
    }
    
    public static void  TestIteratorMap(){
        Map<Integer,String> map1 = new HashMap<Integer,String>();//Map/HashMap都可以
        map1.put(100,"aa");
        map1.put(200,"bb");
        map1.put(300,"cc");
        
        //iterator第一种遍历map的方式(键值对)
         System.out.println("iterator第一种遍历map的方式");
        Set<Entry<Integer,String>> ss = map1.entrySet();//Map.Entry/Entry都可以
        
        for(Iterator<Entry<Integer,String>> iter = ss.iterator();iter.hasNext();){
            Entry<Integer,String> temp =iter.next();//包含键和值
            System.out.println(temp.getKey()+"--"+temp.getValue());
        }  
        
        
        Iterator<Entry<Integer,String>> it = ss.iterator();
        
        while (it.hasNext()) {
            Map.Entry<Integer,String> s = it.next();
            System.out.println("while--"+s.getKey()+"-"+s.getValue());
           
        }
        
        //iterator第二种遍历map的方式(键)
         System.out.println("iterator第二种遍历map的方式");
         
         Set<Integer> keySet = map1.keySet();//获取map所有键的集合
         for(Iterator<Integer> iter1 =keySet.iterator();iter1.hasNext();){
             Integer key = iter1.next();
             System.out.println(key+"--"+map1.get(key));
         }
         
         Iterator<Integer> iter =keySet.iterator();
         while (iter.hasNext()) {
             Integer key = iter.next();
             String value = map1.get(key);
             System.out.println("while--"+key+"-"+value);
               
            }
         
         
    }

}