1.集合轉字符串
List<String> idList= Lists.newArrayList();
idList.add("1");idList.add("2");idList.add("3");
String ids = StringUtils.join(idList,",");
2.字符串轉集合
String str="1,2,3";
//用逗號將字符串分開,得到字符串數組
String[] strs=str.split(",");
//將字符串數組轉換成集合
List list=Arrays.asList(strs);
//查看集合
for (String str : list) {
System.out.println(str);
}