遍历Map方式

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package m.q;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Map.Entry;/** * @author Administrator *  */public class MapTest {public static void main(String[] args) {Map<String, String> map = new HashMap<>();map.put("1", "a");map.put("2", "b");map.put("3", "c");a(map);b(map);c(map);d(map);}/** * @param map *            第一种:二次取值 Map.keySet() 返回此映射中包含的键的 Set 视图。 */public static void a(Map<String, String> map) {for (String key : map.keySet()) {System.out.println("a: key:" + key + " value:" + map.get(key));}}/** * @param map *            entrySet() 返回此映射中包含的映射关系的 Set 视图 */public static void b(Map<String, String> map) {Iterator<Entry<String, String>> iterator = map.entrySet().iterator();while (iterator.hasNext()) {Entry<String, String> entry = iterator.next();System.out.println("b: key:" + entry.getKey() + " value:"+ entry.getValue());}}/** * @param map *            Map.entrySet()遍历key和value */public static void c(Map<String, String> map) {for (Entry<String, String> entry : map.entrySet()) {System.out.println("c: key:" + entry.getKey() + " value:"+ entry.getValue());}}/** * @param map *            Map.value()遍历value(不能遍历key) */public static void d(Map<String, String> map) {for (String v : map.values()) {System.out.println("d: key:" + "" + " value:" + v);}}}
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