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)，香港虚拟主机，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。//main(String[] args) throws Exception {// ArrayList{ArrayList arraylist = new ArrayList();arraylist.add(0, “end”);//指定索引加入值(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listSystem.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，香港虚拟主机，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(); (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(); (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);该方法清空容器删除索引为0的元素删除值为d的元素删除第一个元素(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，网站空间，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2System.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() + “;”);}删除该键对应的值System.out.println(“\n”);}}}

愚者用肉体监视心灵，智者用心灵监视肉体