java----泛型

泛型：jdk 5.0以上版本：

       1，模板编程：class ClassC<T>{

                                   public void method(T t){

                                    }

                               }

       2,<E>：E代表元素类型，

       3，优点：成为模板，节省代码；

                       统一类型，不用强转；

       4，迭代遍历被取代： 统一的遍历方式，通用于数组和集合：for-each   这里注意这有当

                                          类中实现 Iterable 接口；在set和collection可以，但在map中没有这个

                                          Iterable 接口；

                  Sting[] ss={"wjz","hxz","lcy","zhang3"}

                    /* for(int i=0;i<ss.length;i++){

                                String s=ss[i];

                                System.out.println(s);

                       }

                     */

                        for(String s:ss){

                        System.out.println(s);

                         }

     2，    collection<String> c=new HashSet<String>();

                     c.add("hxz");

                     c.add("lcy");

                     c.add("zhang3");

                  /*

                    Iterator it=c.iterator();

                    while(it.hasNext()){

                    String s=(String)it.next();

                    System.out.println(s);

                     }

                   */

                 for(String s:c){

                   System.out.println(s);

                  }