Java容器小结和使用示例
2013-04-25 09:16 zhenjing 阅读(4740) 评论(0) 编辑 收藏 举报Java容器集合类的区别用法: http://www.cnblogs.com/sunliming/archive/2011/04/05/2005957.html
参见:http://dafeng.wang.blog.163.com/blog/static/1281691932009109115513940/
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"); } } }
作者:zhenjing.chen
出处:http://www.cnblogs.com/zhenjing/
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