Sunspl

          Hello,everyone,i am sun. 天道酬勤,笨鳥先飛.
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          數據加載中……

          Java里的list,set,map操作方法(練習)

          //ArrayList
          {
          ArrayList arraylist=new ArrayList();
          arraylist.add(0,"end");//指定索引加入值
          //需注意的是,如果現有2個值,我加入索引為5的那么就會出現異常
          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.print("\nArrayList\'s lastIndexOf(\"0\") is "+arraylist.lastIndexOf("0"));
          }
          //Arrays
          {
          String []array=new String[]{"a","b","c"};
          List list=Arrays.asList(array);
          System.out.println("\nArrays:");
          for(int i=0;i<list.size();i++){
          System.out.print(list.get(i)+";");
          }
          System.out.print("\nArrays\'s length is "+array.length);//打印數組的長度
          }
          //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("\nCollections:");
          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);//拷貝list2的數據進list
          System.out.println("\n"+list);
          Collections.swap(list,2,1);//調換索引為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);//一個準容器類型,確切的歸類它不是容器
          System.out.println("EventObject:");
          System.out.println(eventobject.getSource());
          System.out.println(eventobject.equals(s2));
          }
          //HashMap
          {
          HashMap hashmap=new HashMap();//一個速度最快的容器
          hashmap.put("0","c");
          hashmap.put("1","a");
          hashmap.put("2","b");
          hashmap.put("3","a");
          System.out.println("HashMap:");
          System.out.println(hashmap);//該容器有其內部的排序方式
          Set set=hashmap.keySet();//獲取全部鍵
          Iterator iterator=set.iterator();
          while(iterator.hasNext()){
          System.out.print(hashmap.get(iterator.next())+";");
          }
          }
          //HashSet
          {
          HashSet hashset=new HashSet();//一個絕對不能重復的類型
          hashset.add("c");
          hashset.add("b");
          hashset.add("a");
          hashset.add("a");
          hashset.add("b");
          System.out.println("\nHashSet:");
          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();//一個完全可以由其他容器替換的老容器類型
          hashtable.put("0","c");
          hashtable.put("1","a");
          hashtable.put("3","c");
          hashtable.put("2","b");
          System.out.println("\nHashtable:");
          Enumeration enumeration=hashtable.elements();//獲取元素,Enumeration已經不是主流,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("\nIdentityHashMap:");
          System.out.println(identityhashmap);
          System.out.println(identityhashmap.containsKey("3"));//是否包含這個鍵
          System.out.println(identityhashmap.containsValue("a"));//是否包含值
          Set set=identityhashmap.entrySet();//傳為Set類型
          System.out.println(set);
          set=identityhashmap.keySet();//全部鍵
          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"));//是否包含這個鍵
          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();//它包含了幾種Set的屬性但卻沒有自己的特色
          linkedhashset.add("c");
          linkedhashset.add("a");
          linkedhashset.add("a");
          linkedhashset.add("b");
          System.out.println("\nLinkedHashSet:");
          System.out.println(linkedhashset);
          System.out.println(linkedhashset.contains("a"));//是否包含對象
          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("\nLinkedList:");
          System.out.println(linkedlist);
          //linkedlist.clear();//該方法清空容器
          //linkedlist.remove(0);//刪除索引為0的元素
          //linkedlist.remove("d");//刪除值為d的元素
          //linkedlist.removeFirst();//刪除第一個元素
          //linkedlist.removeLast();//刪除最后一個元素
          for(int i=0;i<linkedlist.size();i++){
          System.out.print(linkedlist.get(i)+";");
          }
          }
          //Stack
          {
          Stack stack=new Stack();//堆棧
          stack.add("b");
          stack.add(0,"c");
          stack.push("d");
          stack.add("e");
          stack.push("a");
          Enumeration enumeration=stack.elements();
          System.out.println("\nStack:");
          while(enumeration.hasMoreElements()){
          System.out.print(enumeration.nextElement()+";");
          }
          //后進先出
          System.out.println("\n"+stack.peek());
          System.out.println(stack.pop());
          System.out.println(stack.contains("d")+";"+stack.contains("a"));//是否包含該元素,有趣的事情發生了
          System.out.println(stack.search("c"));//非常有用的屬性,檢索,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("\nTreeMap:");//可以對鍵排序
          System.out.println(treemap);
          System.out.println(treemap.firstKey());//返回第一個鍵
          Set set=treemap.keySet();
          Iterator iterator=set.iterator();
          while(iterator.hasNext()){
          System.out.print(treemap.get(iterator.next())+";");
          }
          }
          //TreeSet
          {
          TreeSet treeset=new TreeSet();//自動排序內容
          treeset.add("b");
          treeset.add("a");
          treeset.add("c");
          treeset.add("d");
          System.out.println("\nTreeSet:");
          System.out.println(treeset);
          System.out.println(treeset.first());//返回第一個元素
          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("\nVector:");
          System.out.println(vector);
          vector.set(2,"h");//替換掉指定索引的元素
          System.out.println(vector);
          Object []str=vector.toArray();
          for(int i=0;i<str.length;i++){
          System.out.print(str[i]+";");
          }
          vector.setSize(2);//重新設置大小為2
          System.out.println("\n"+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("\nWeakHashMap:");
          System.out.println(weakhashmap);
          System.out.println(weakhashmap.containsKey("3"));//是否包含鍵
          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");//刪除該鍵對應的值
          //weakhashmap.get("1");//獲取指定鍵的值
          }
          }

          posted on 2008-06-25 17:33 JavaSuns 閱讀(3875) 評論(0)  編輯  收藏


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