关于把list转换成key value的map有很多博客上都有实现,这里是一个吧value放入到集合中去
List<String> list = Lists.newArrayList("1", "2", "3", "1"); Map<String, List<String>> map = list.stream().collect(Collectors.toMap(key -> key, value -> Lists.newArrayList(value), (List<String> newValueList, List<String> oldValueList) -> { oldValueList.addAll(newValueList); return oldValueList; })); System.out.println(JSON.toJSONString(map));
类似的,你的list泛型可以是一个bean,取bean的属性当key或者value,转换成一个集合
结果: {"1":["1","1"],"2":["2"],"3":["3"]}