关于java的集合类,以及HashMap中Set的用法!

???????????????????? + arraylist.lastIndexOf("0"));
???????? }
???????? //???? Arrays
???????? {
???????????? String[] array = new String[] { "a", "b", "c" };
???????????? List list = Arrays.asList(array);
???????????? System.out.println(" Arrays:");
???????????? for (int i = 0; i < list.size(); i++) {
???????????????? System.out.print(list.get(i) + ";");
???????????? }
???????????? System.out.print(" Arrays's length is " + array.length);//打印数组的长度
???????? }
???????? //???? Collections
???????? {
???????????? String[] array = new String[] { "a", "b", "c" };
???????????? List list = Arrays.asList(array);
???????????? Collections.fill(list, "Fill");//用Fill填充全部元素
???????????? System.out.println(" Collections:");
???????????? for (int i = 0; i < list.size(); i++) {
???????????????? System.out.print(list.get(i) + ";");
???????????? }
???????????? array = new String[] { "1", "2", "3" };
???????????? List list2 = Arrays.asList(array);
???????????? Collections.copy(list, list2);//拷贝list2的数据进list
???????????? System.out.println(" " + list);
???????????? Collections.swap(list, 2, 1);//调换索引为1和2的元素的位置
???????????? System.out.println(list);
???????? }
???????? //???? EventObject
???????? {
???????????? String s = "hello";
???????????? String s2 = s;
???????????? EventObject eventobject = new EventObject(s);//一个准容器类型，确切的归类它不是容器
???????????? System.out.println("EventObject:");
???????????? System.out.println(eventobject.getSource());
???????????? System.out.println(eventobject.equals(s2));
???????? }
???????? //???? HashMap
???????? {
???????????? HashMap hashmap = new HashMap();//一个速度最快的容器
???????????? hashmap.put("0", "c");
???????????? hashmap.put("1", "a");
???????????? hashmap.put("2", "b");
???????????? hashmap.put("3", "a");
???????????? System.out.println("HashMap:");
???????????? System.out.println(hashmap);//该容器有其内部的排序方式
???????????? Set set = hashmap.keySet();//获取全部键
???????????? Iterator iterator = set.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(hashmap.get(iterator.next()) + ";");
???????????? }
???????? }
???????? //???? HashSet
???????? {
???????????? HashSet hashset = new HashSet();//一个绝对不能重复的类型
???????????? hashset.add("c");
???????????? hashset.add("b");
???????????? hashset.add("a");
???????????? hashset.add("a");
???????????? hashset.add("b");
???????????? System.out.println(" HashSet:");
???????????? System.out.println(hashset);
???????????? Iterator iterator = hashset.iterator();//取出元素
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(iterator.next() + ";");
???????????? }
???????? }
???????? //???? Hashtable
???????? {
???????????? Hashtable hashtable = new Hashtable();//一个完全可以由其他容器替换的老容器类型
???????????? hashtable.put("0", "c");
???????????? hashtable.put("1", "a");
???????????? hashtable.put("3", "c");
???????????? hashtable.put("2", "b");
???????????? System.out.println(" Hashtable:");
???????????? Enumeration enumeration = hashtable.elements();//获取元素，Enumeration已经不是主流，Iterator是它的下一代替代品
???????????? while (enumeration.hasMoreElements()) {
???????????????? System.out.print(enumeration.nextElement() + ";");
???????????? }
???????? }
???????? //???? IdentityHashMap
???????? {
???????????? IdentityHashMap identityhashmap = new IdentityHashMap();
???????????? identityhashmap.put("0", "c");
???????????? identityhashmap.put("1", "a");
???????????? identityhashmap.put("3", "b");
???????????? identityhashmap.put("2", "a");
???????????? System.out.println(" IdentityHashMap:");
???????????? System.out.println(identityhashmap);
???????????? System.out.println(identityhashmap.containsKey("3"));//是否包含这个键
???????????? System.out.println(identityhashmap.containsValue("a"));//是否包含值
???????????? Set set = identityhashmap.entrySet();//传为Set类型
???????????? System.out.println(set);
???????????? set = identityhashmap.keySet();//全部键
???????????? System.out.println(set);
???????? }
???????? //???? LinkedHashMap
???????? {
???????????? LinkedHashMap linkedhashmap = new LinkedHashMap();
???????????? linkedhashmap.put("0", "b");
???????????? linkedhashmap.put("2", "a");
???????????? linkedhashmap.put("1", "c");
???????????? linkedhashmap.put("3", "b");
???????????? System.out.println("LinkedHashMap:");
???????????? System.out.println(linkedhashmap);
???????????? System.out.println(linkedhashmap.containsKey("2"));//是否包含这个键
???????????? System.out.println(linkedhashmap.containsValue("c"));//是否包含值
???????????? Set set = linkedhashmap.keySet();
???????????? Iterator iterator = set.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(linkedhashmap.get(iterator.next()) + ";");
???????????? }
???????? }
???????? //???? LinkedHashSet
???????? {
???????????? LinkedHashSet linkedhashset = new LinkedHashSet();//它包含了几种Set的属性但却没有自己的特色
???????????? linkedhashset.add("c");
???????????? linkedhashset.add("a");
???????????? linkedhashset.add("a");
???????????? linkedhashset.add("b");
???????????? System.out.println(" LinkedHashSet:");
???????????? System.out.println(linkedhashset);
???????????? System.out.println(linkedhashset.contains("a"));//是否包含对象
???????????? Iterator iterator = linkedhashset.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(iterator.next() + ";");
???????????? }
???????? }
???????? //???? LinkedList
???????? {
???????????? LinkedList linkedlist = new LinkedList();//自由使用是它的特色
???????????? linkedlist.add("a");
???????????? linkedlist.add(1, "c");
???????????? linkedlist.addLast("b");
???????????? linkedlist.addFirst("d");
???????????? System.out.println(" LinkedList:");
???????????? System.out.println(linkedlist);
???????????? //???? linkedlist.clear();//该方法清空容器
???????????? //???? linkedlist.remove(0);//删除索引为0的元素
???????????? //???? linkedlist.remove("d");//删除值为d的元素
???????????? //???? linkedlist.removeFirst();//删除第一个元素
???????????? //???? linkedlist.removeLast();//删除最后一个元素
???????????? for (int i = 0; i < linkedlist.size(); i++) {
???????????????? System.out.print(linkedlist.get(i) + ";");
???????????? }
???????? }
???????? //???? Stack
???????? {
???????????? Stack stack = new Stack();//堆栈
???????????? stack.add("b");
???????????? stack.add(0, "c");
???????????? stack.push("d");
???????????? stack.add("e");
???????????? stack.push("a");
???????????? Enumeration enumeration = stack.elements();
???????????? System.out.println(" Stack:");
???????????? while (enumeration.hasMoreElements()) {
???????????????? System.out.print(enumeration.nextElement() + ";");
???????????? }
???????????? //???? 后进先出
???????????? System.out.println(" " + stack.peek());
???????????? System.out.println(stack.pop());
???????????? System.out.println(stack.contains("d") + ";" + stack.contains("a"));//是否包含该元素,有趣的事情发生了
???????????? System.out.println(stack.search("c"));//非常有用的属性，检索，但是由后向前的排列
???????? }
???????? //???? TreeMap
???????? {
???????????? TreeMap treemap = new TreeMap();
???????????? treemap.put("0", "d");
???????????? treemap.put("2", "a");
???????????? treemap.put("1", "b");
???????????? treemap.put("3", "c");
???????????? System.out.println(" TreeMap:");//可以对键排序
???????????? System.out.println(treemap);
???????????? System.out.println(treemap.firstKey());//返回第一个键
???????????? Set set = treemap.keySet();
???????????? Iterator iterator = set.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(treemap.get(iterator.next()) + ";");
???????????? }
???????? }
???????? //???? TreeSet
???????? {
???????????? TreeSet treeset = new TreeSet();//自动排序内容
???????????? treeset.add("b");
???????????? treeset.add("a");
???????????? treeset.add("c");
???????????? treeset.add("d");
???????????? System.out.println(" TreeSet:");
???????????? System.out.println(treeset);
???????????? System.out.println(treeset.first());//返回第一个元素
???????????? Iterator iterator = treeset.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(iterator.next() + ";");
???????????? }
???????? }
???????? //???? Vector
???????? {
???????????? Vector vector = new Vector();
???????????? vector.add(0, "b");
???????????? vector.add("a");
???????????? vector.addElement("d");
???????????? vector.add("c");
???????????? System.out.println(" Vector:");
???????????? System.out.println(vector);
???????????? vector.set(2, "h");//替换掉指定索引的元素
???????????? System.out.println(vector);
???????????? Object[] str = vector.toArray();
???????????? for (int i = 0; i < str.length; i++) {
???????????????? System.out.print(str[i] + ";");
???????????? }
???????????? vector.setSize(2);//重新设置大小为2
???????????? System.out.println(" " + vector);
???????? }
???????? //???? WeakHashMap
???????? {
???????????? WeakHashMap weakhashmap = new WeakHashMap();
???????????? weakhashmap.put("1", "b");
???????????? weakhashmap.put("2", "c");
???????????? weakhashmap.put("0", "d");
???????????? weakhashmap.put("3", "a");
???????????? System.out.println(" WeakHashMap:");
???????????? System.out.println(weakhashmap);
???????????? System.out.println(weakhashmap.containsKey("3"));//是否包含键
???????????? System.out.println(weakhashmap.containsValue("d"));//是否包含值
???????????? Set set = weakhashmap.entrySet();
???????????? Iterator iterator = set.iterator();
???????????? while (iterator.hasNext()) {
???????????????? System.out.print(iterator.next() + ";");
???????????? }
???????????? //???? weakhashmap.remove("2");//删除该键对应的值
???????????? //???? weakhashmap.get("1");//获取指定键的值
???????? }
???? }
}转自：http://hi.baidu.com/fyears/blog/item/52329711622e007ccb80c465.html