java——Map集合遍历总结

package test1;

import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.HashMap;
import java.util.Iterator;

public class Test {
	public static void main(String[] args){
		 
		 Map<String,Integer> scores = new HashMap<String,Integer>();
		 scores.put("Jim", 100);
		 scores.put("Kate", 10);
		 
		 //第一种
		 Set<String> names = scores.keySet();//获取集合中所有key-value的key组成的Set集合
		 //加强循环
		 for (String key : names) {
		    System.out.println(scores.get(key));
		 }

		 System.out.println("********************");
		 
		 //迭代器
		 Iterator<String> iterator = names.iterator();
		 while(iterator.hasNext()) {
		    String key = iterator.next();
		    int value = scores.get(key);
		    System.out.println(value);
		 }
		 
		 System.out.println("********************");	
		 
		 //第二种
		 Set<Entry<String, Integer>> entries =  scores.entrySet();//将HashMap集合中key-value用Entry对象包含
		 //加强循环
		 for (Entry<String, Integer> entry : entries) {
		    int value = entry.getValue();
		    System.out.println(value);
		 }
		 System.out.println("********************");
		 
		 //迭代器
		 Iterator<Entry<String, Integer>> it = entries.iterator();
		 while(it.hasNext()) {
		    Entry<String, Integer> entry = it.next();
		    int value = entry.getValue();
		    System.out.println(value);
		 }
		 System.out.println("********************");	
	}
}