package demo;
import <a href='http://www.bangbangdao.com/special/618658fc2711d' target='_blank' >java</a>.util.ArrayList;
import <a href='http://www.bangbangdao.com/special/618658fc2711d' target='_blank' >java</a>.util.Arrays;
import <a href='http://www.bangbangdao.com/special/618658fc2711d' target='_blank' >java</a>.util.List;
public class ListDemo {
public static void main(String[] args) {
String str = "A,B";
// 字符串转List
List<String> list = new ArrayList<>(Arrays.asList(str.split(",")));
list.add("C");
// List转字符串
String line = String.join(",", list);
System.out.println(line);
// A,B,C
}
} Arrays.asList 返回的List不能进行添加操作，需要用ArrayList包装一下
UnsupportedOperationException
