Map接口常用方法的示例
import java.util.Collection;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;public class MapPractice {public static void main(String[] args) {Map<String, String> map = new HashMap<String, String>(); //实例化一个map对象//向map中添加内容map.put("A", "hebei");map.put("C", "beijing");map.put("B", "zhongguo");//判断容器中是否 存在A这个键值if(map.containsKey("A")){System.out.println("A is available");}//判断容器中是否 存在beijing这个值if(map.containsValue("beijing")){System.out.println("Beijing welcom you");}//返回map中的所有key的值Set<String> set = map.keySet();Iterator<String> iterator = set.iterator();while(iterator.hasNext()){System.out.print(iterator.next()+" ");}System.out.println();//返回map中的所有value的值Collection<String> collection = map.values();for (String string : collection) {System.out.print(string+" ");}System.out.println();//返回键值队Set<Map.Entry<String, String>> set2 = map.entrySet();Iterator<Map.Entry<String, String>> iterator2 = set2.iterator();while(iterator2.hasNext()){Map.Entry<String, String> entry = iterator2.next();System.out.println("key-----"+entry.getKey()+" "+"value-----"+entry.getValue());}}}?运行结果：
A is availableBeijing welcom youA B C hebei zhongguo beijing key-----A value-----hebeikey-----B value-----zhongguokey-----C value-----beijing
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