关于一些可以相互转换的数据类型的方法

1.String转int

String str = "123";
int num = Integer.parseInt(str);

2.int转String

int num = 123;
String str = String.valueOf(num);

3.数组转String

int[] arr = {1, 2, 3};
String str = Arrays.toString(arr);  

4.String 转 char 数组

String str = "Hello";
char[] charArray = str.toCharArray();

5.String转Integer

String str = "123";
Integer obj = Integer.valueOf(str);

6.set转list

Set<String> set = new HashSet<>();
set.add("A");
set.add("B");
List<String> list = new ArrayList<>(set)

7.list转set

List<String> list = new ArrayList<>();
list.add("A");
list.add("B");
Set<String> set = new HashSet<>(list);