java 遍历 Iterator foreach for

package test;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Iterator;

import java.util.Map.Entry;

import java.util.Set;

public class bainli {

public static void main(String[] args) {

Hashbianli();

ArrayHash();

}

//对于HashMap

public static void Hashbianli(){

HashMap<String,Integer> map = new HashMap<String,Integer>();

//转为entry

Set<Entry<String,Integer>> set1 = map.entrySet();

//Iterator遍历

Iterator <Entry<String, Integer>> it = set1.iterator();

while(it.hasNext()){

Entry<String, Integer> entry = it.next();

System.out.println(entry.getKey()+" "+entry.getValue());

}

//foreach 遍历

for(Entry<String,Integer> entry:set1){

System.out.println(set1);

System.out.println("xxx"+entry.getKey()+"yyy"+entry.getValue());

}

}

public static void ArrayHash(){

//对于ArrayList、HashSet

Set<String> set = new HashSet<String>();

set.add("abc");

set.add("def");

set.add("ghi");

//Iterator遍历

Iterator<String> iterator = set.iterator();

while(iterator.hasNext()){

System.out.println(iterator.next().toUpperCase()+"");

}

//for

for(Object temp:set){

System.out.println(temp);

System.out.println(temp.toString().toLowerCase());

}

}

}