java map的遍历
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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