数组

1.判断数组内是否有反复元素

/**判断String数组内是否有反复元素*/
    public static boolean checkRepeat(String[] strings){
        boolean result = false;
        List<String> list = new ArrayList<>();
        for (int i=0; i < strings.length; i++){
            if (!list.contains(strings[i])){
                list.add(strings[i]);
            }
        }
        if (list.size() < strings.length){
            result = true;
            return result;
        }else {
            return result;
        }
    }

测试：

后果：

2.数组转为List汇合

（1）Collections.addAll()办法

System.out.println("----------数组转为List汇合：Collections.addAll()办法-----------------------------------");
        String[] strings = {"aa","bb","cc"};
        List<String> list3 = new ArrayList<>();
        Collections.addAll(list3, strings);
        System.out.println(list3.toString());

测试：

（2）循环增加数组元素的办法

System.out.println("----------数组转为List汇合：循环增加数组元素的办法-----------------------------------");
        String[] string4 = {"aa","bb","cc","dd"};
        List<String> list4 = new ArrayList<>();
        for (int i=0; i<string4.length; i++){
            list4.add(string4[i]);
        }
        System.out.println(list4.toString());

测试：

（3）Arrays.asList()办法
返回一个受指定数组反对的固定大小的列表，不能做Add、Remove等操作

System.out.println("----------数组转为List汇合：Arrays.asList()办法-----------------------------------");
        String[] string5 = {"aa","bb","cc","dd","ee"};
        List<String> list5 = new ArrayList<>();
        list5 = Arrays.asList(string5);
        System.out.println(list5.toString());

测试：