map的四种遍历方式，map遍历元素

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map的四种遍历方式，map遍历元素

list 遍历元素
http://blog.csdn.net/sunrainamazing/article/details/71577662
set遍历元素
http://blog.csdn.net/sunrainamazing/article/details/71577893
map遍历元素
http://blog.csdn.net/sunrainamazing/article/details/71580051

package sun.rain.amazing.traversal;import java.util.*;import java.util.Map.Entry;/** * Created by sunRainAmazing on SUN_RAIN_AMAZING * @author sunRainAmazing */public class TraversalMap {   //http://www.cnblogs.com/toSeeMyDream/p/5577601.html    public static void main(String[] args){        Map<String,Integer> map = new HashMap<String,Integer>();        map.put("tom1",1);        map.put("tom2",2);        map.put("tom3",3);        map.put("tom5",5);        map.put("tom4",4);        //1.4版本之前        Iterator it = map.entrySet().iterator();        while (it.hasNext()) {            Map.Entry entry = (Map.Entry) it.next();            Object key = entry.getKey();            Object value = entry.getValue();            System.out.print(key+" -->: "+value+"\t");        }        System.out.println("\n================");        //1.5 for-each 循环操作        for(String o : map.keySet()){            System.out.print (map.get(o)+"\t");        }        //方法一: 用entrySet()          //返回的 set 中的每个元素都是一个 Map.Entry 类型。        // 推荐，尤其是容量大时        System.out.println("\n=====用entrySet()=======");        Iterator it1 = map.entrySet().iterator();        while(it1.hasNext()){            Map.Entry m=(Map.Entry)it1.next();            System.out.println("[name = " + m.getKey()                 + "] age = " + m.getValue());        }        // 方法二：jdk1.5支持，用entrySet()和For-Each循环()        System.out.println("\n=用entrySet()和For-Each===");        for (Map.Entry<String, Integer> m : map.entrySet()) {            System.out.println("[name = " + m.getKey() + "] age = " + m.getValue());        }        // 方法三：用keySet() 普遍使用，二次取值        System.out.println("\n=====用keySet()=======");        Iterator it2 = map.keySet().iterator();        while (it2.hasNext()){            String key = (String) it2.next();            System.out.println("[name = " + key                 + "] age = " + map.get(key) );        }        // 方法四：jdk1.5支持，用keySEt()和For-Each循环        System.out.println("\n=====用keySet()和For-Each=====");        for(Object key: map.keySet()){            System.out.println("[name = " + key                 + "] age = " + map.get(key) );        }    }    /**     * entrySet()     * @param map     */    private void printMap(Map<String,Integer> map){        Set<Entry<String, Integer>> entries = map.entrySet( );        if(entries != null) {            Iterator  iterator = entries.iterator( );            while(iterator.hasNext( )) {                Map.Entry  entry =                    (Entry<String, Integer>) iterator.next( );//              Object key = entry.getKey();//              Object value = entry.getValue();                System.out.println(                                           entry.getKey()+"\t\t:"+entry.getValue());            }        }    }}

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