Java Collection(集合)
集合中的一些技巧:
通过Collections类的静态方法,可以对集合进行一些操作
1 java.util.List<Integer> numbers=Arrays.asList(12,5,6,8,11,4); 2 Collections.sort(numbers);//排序 3 System.out.println(numbers); 4 Collections.reverse(numbers);//反转 5 System.out.println(numbers); 6 Collections.shuffle(numbers);//打乱顺序 7 System.out.println(numbers); 8 //最大值、最小值 9 Collections.max(numbers); 10 Collections.min(numbers);
防止并发访问集合
1 java.util.List<String> list=Collections.synchronizedList(new ArrayList<String>()); 2 Map<Integer, String> map=Collections.synchronizedMap(new HashMap<Integer,String>());
只读集合
java.util.List<String> words=Collections.unmodifiableList(new ArrayList<String>());