Java study notes-stream().map use

 The operation in stream().map() must return a String, so the operation in map cannot be equals, etc., but can be toString, etc.

 

 

The test code is as follows:

public class Test {
    public static void main(String[] args) {

        List<String> list = new ArrayList<String>();
        list.add("小明");
        list.add("小周");
        list.add("小艾");
        list.add("小张");
        // 对所有元素进行操作
        List<String> collect = list.stream().map(item -> item.toString()).collect(Collectors.toList());
        System.out.println(collect);

    }


}