Java容器小结和使用示例

import java.lang.String;import java.util.*;public class JAVAContainer {    // Interfaces:    // Interface Iterator: hasNext(),  next(), remove() ---- 所有容器通用的遍历方式。    // Interface Collection：add(E e)，remove(Object o), clear(), isEmpty(), size(), iterator(), toArray() ---- 所有单值容器(map除外)的公共接口。     // Interface Map: put(K key, V value), get(Object key), remove(Object key), clear()，isEmpty()，size(), keySet(), entrySet(), values()  ---- 所有K-V容器的公共接口，常见class: HashMap, Hashtable, IdentityHashMap, LinkedHashMap, ConcurrentHashMap    // Interface Map.Entry: getKey(), getValue(), setValue(V value) ---- 用于遍历Map容器。    //    public static void main(String[] args) throws Exception {        // ArrayList        {            ArrayList arraylist = new ArrayList();            arraylist.add(0, "end");//指定索引加入值            // 需注意的是，如果现有2个值，我加入索引为5的那么就会出现异常            for (int i = 0; i < 2; i++) {                arraylist.add(i, String.valueOf(i));            }            System.out.println("ArrayList:");            for (int i = 0; i < arraylist.size(); i++) {                System.out.print(arraylist.get(i) + ";");            }            arraylist.add("0");//直接加入值到ArrayList的最后            arraylist.add("0");            System.out.println("");            System.out.print(" ArrayList's lastIndexOf(\"0\") is " + arraylist.lastIndexOf("0"));             for (Object val : arraylist) {                System.out.print( val + ";");            }            System.out.println("\n");        }        // 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                        System.out.println("");            for (Object val : array) {                System.out.print( val + ";");            }            System.out.println("\n");        }        // 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);            System.out.println("\n");        }        // 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));            System.out.println("\n");        }        // 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()) + ";");            }            System.out.println("");            System.out.println("HashMap: K-V");            iterator = set.iterator();            while (iterator.hasNext()) {                Object key = iterator.next();                System.out.print(key+":"+hashmap.get(key) + ";");            }            System.out.println("");            System.out.println("HashMap(Entry): K-V");            Set<Map.Entry> kvSet = hashmap.entrySet();            Iterator<Map.Entry> it = kvSet.iterator();            while (it.hasNext()){                Map.Entry entry = it.next();                System.out.print( entry.getKey()+":" + entry.getValue() +";");            }             System.out.println("\n");        }        // 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() + ";");            }            System.out.println("\n");        }        // 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() + ";");            }            System.out.println("\n");        }        // 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);            System.out.println("\n");        }        // 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()) + ";");            }            System.out.println("\n");        }        // 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() + ";");            }            System.out.println("\n");        }        // 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) + ";");            }            System.out.println("\n");        }        // 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            System.out.println("\n");        }        // 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()) + ";");            }            System.out.println("\n");        }        // 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() + ";");            }            System.out.println("\n");        }        // 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);            System.out.println("\n");        }        // 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            System.out.println("\n");        }    }}