package demo;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class ListDemo {
public static void main(String[] args) {
String str = "A,B";
// 字符串轉List
List<String> list = new ArrayList<>(Arrays.asList(str.split(",")));
list.add("C");
// List轉字符串
String line = String.join(",", list);
System.out.println(line);
// A,B,C
}
}
Arrays.asList 返回的List不能進行添加操作,需要用ArrayList包裝一下
UnsupportedOperationException