Map集合遍历总结

Map集合遍历共有两种

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

public class Test3 {

	public static void main(String[] args) {

		Map<String, Integer> scores = new HashMap<String, Integer>();
		scores.put("Tim", 500);
		scores.put("Jim", 532);
		//Map集合的遍历（两种）
		//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) {
			int value = scores.get(key);
			System.out.print(value+"	");
		}
		System.out.println();
		
		//迭代器
		Iterator<String> iterator = names.iterator();//将集合中的数据转存
		while(iterator.hasNext()) {
			String key = iterator.next();
			int value = scores.get(key);
			System.out.print(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) {
			String key = entry.getKey();
			int value = entry.getValue();
			System.out.print(value+"	");
		}
		System.out.println();
		
		//迭代器
		Iterator<Entry<String, Integer>> it = entries.iterator();//将集合中的数据转存
		while(it.hasNext()) {
			Entry<String, Integer> entry = it.next();
			String key = entry.getKey();
			int value = entry.getValue();
			System.out.print(value+"	");
		}
		System.out.println();
	}
}