map有关实例代码

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package qq;import java.util.ArrayList;import java.util.HashMap;import java.util.Hashtable;import java.util.Iterator;import java.util.Map;import java.util.TreeMap;public class HsahTreeMap {public static void main(String[] args) {Map<String, String> map = new HashMap<String, String>();map.put("a", "aaa");map.put("b", "bbb");map.put("c", "ccc");map.put("d", "ddd");Iterator<String> iterator = map.keySet().iterator();while (iterator.hasNext()) {Object key = iterator.next();System.out.println("map.get(key) is :" + map.get(key)); //输出是无序的}System.out.println(map);System.out.println(map.get("a").toString());  //有没有toString都是一样的//还有一种遍历方式for(Object o:map.keySet()){Object value = map.get(o);System.out.println("o:"+o);System.out.println("value:"+value);}ArrayList<String> list = new ArrayList<String>();list.add("a");list.add("b");System.out.println(list);// 定义HashTable,用来测试Hashtable<String, String> tab = new Hashtable<String, String>();tab.put("a", "aaa");tab.put("b", "bbb");tab.put("c", "ccc");tab.put("d", "ddd");Iterator<String> iterator_1 = tab.keySet().iterator();while (iterator_1.hasNext()) {Object key = iterator_1.next();System.out.println("tab.get(key) is :" + tab.get(key));   //输出是无序的}TreeMap<String, String> tmp = new TreeMap<String, String>();tmp.put("a", "aaa");tmp.put("b", "bbb");tmp.put("c", "ccc");tmp.put("d", "ddd");Iterator<String> iterator_2 = tmp.keySet().iterator();while (iterator_2.hasNext()) {Object key = iterator_2.next();System.out.println("tmp.get(key) is :" + tmp.get(key));  //倒叙输出}}}
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