Collection类及常用API

Collection类及常用API

Collection—类集工具类，定义了若干用于类集和映射的算法，这些算法被定义为静态方法，具体查看api文档;

a)  public static void sort(List<T> liet)

b)  public static int binarySearch(List<T> list,T key)

c)  public static void reverse(List<?> list)

d)  public static void shuffle(List<?> list)

e)  public static void swap(List<?> list,int i,int j)

f)   public static <T> void fill(List<? super T> list,T obj)

         List<String> nList=new ArrayList<String>();
         nList.add("zhangsan");
         nList.add("lisi");
         nList.add("wangwu");
         nList.add("zhaoliu");
         nList.add("tianqi");
         System.out.println("操作前");
         for(String s:nList){
             System.out.print(s+" ");
         }

         System.out.println();
         System.out.println("交换顺序后");
         Collections.swap(nList,1,2);
         for(String s:nList){
             System.out.print(s+" ");
         }

         System.out.println();
         System.out.println("自然排序后");
         Collections.sort(nList);
         for(String s:nList){
             System.out.print(s+" ");
         }

         System.out.println();
         System.out.println("二分法查找");
         System.out.println(Collections.binarySearch(nList, "zhaoliu"));

         System.out.println("打乱顺序");
         Collections.shuffle(nList);
         for(String s:nList){
             System.out.print(s+" ");
         }

         System.out.println();
         System.out.println("填充");
         Collections.fill(nList, "jay");
         for(String s:nList){
             System.out.print(s+" ");
         }

输出结果：

操作前

zhangsan lisi wangwu zhaoliu tianqi

交换顺序后

zhangsan wangwu lisi zhaoliu tianqi

自然排序后

lisi tianqi wangwu zhangsan zhaoliu

二分法查找

4

打乱顺序

zhaoliu tianqi wangwu zhangsan lisi

填充

jay jay jay jay jay