java map的遍历_JAVA_编程开发_程序员俱乐部

有时候需要对map进行排序，什么会进行对map的遍历，以下是对map的遍历的方法。欢迎指正。

package TEST;

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

/**
 * @author Administrator
 *
 */
public class TraversalMap {
	public static void main(String[] args) {
		Map<Object, Object> map = buildMap();
//		TraversalMap1(map);
//		TraversalMap2(map);
		TraversalMap3(map);
//		TraversalMap4(map);
	}
	/**
	 * @return map
	 */
	public static Map<Object, Object> buildMap(){
		Map<Object, Object> map = new HashMap<Object, Object>();
		map.put("王力宏", "你不知道的事");
		map.put("梁静茹", "可惜不是你	");
		map.put("凤凰传奇", "荷塘月色");
		map.put("王菲", "红豆");
		map.put("周杰伦", "半兽人");
		map.put("邓丽君", "好久不见");
		return map;
	}
	
	public static void TraversalMap1(Map<Object, Object> map){
		Set<Object> set = map.keySet();
		Iterator<Object> it = set.iterator();
		while(it.hasNext()){
			Object o_key = it.next();
			System.out.println("map : <key : "+o_key+"--value : "+map.get(o_key)+">");
		}
	}
	
	
	/**
	 * @param map
	 * 得到map的values
	 */
	public static void TraversalMap2(Map<Object, Object> map){
		Collection<Object> c = map.values();
		Iterator<Object> it = c.iterator();
		while(it.hasNext()){
			Object o_key = it.next();
			System.out.println("map : <key : "+"****"+"--value : "+o_key+">");
		}
	}
	
	
	/**使用Map.Entry得到这一个map，然后分离出key和values
	 * @param map
	 */
	public static void TraversalMap3(Map<Object, Object> map){
		Set<Entry<Object,Object>> set = map.entrySet();
		Iterator<Entry<Object, Object>> it = set.iterator();
		while(it.hasNext()){
			Entry<Object, Object> map_entry = it.next();
			System.out.println("map : <key : "+map_entry.getKey()+"--value : "+map_entry.getValue()+">");
		}
	}
	
	
	/**
	 * 简单点的
	 * @param map
	 */
	public static void TraversalMap4(Map<Object, Object> map){
		for(Object o: map.values()){
		System.out.println("map : <key : "+getKey(map, o)+"--value : "+o+">");
		}
	}
	
	/**
	 * 根据value得到key
	 * @param Map
	 * @param Object
	 */
	public static Object getKey(Map<Object, Object> map,Object value){
		Set<Object> set = map.keySet();
		Iterator<Object> it = set.iterator();
		while(it.hasNext()){
			Object temp_o = it.next();
			if(map.get(temp_o).equals(value)){
				return temp_o;
			}
		}
		return null;
	}
	
	
	
	
}

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