java8之list集合中取出某一属性的方法

List<User> list = new ArrayList<User>();
User user1 = new User("第一位","用户1");
list.add(user1);
User user2 = new User("第二位","用户2");
list.add(user2);
User user3 = new User("第三位","用户3");
list.add(user3);
List<String> tableNames=list.stream().map(User::getMessage).collect(Collectors.toList());
System.out.println("输出第一个："+tableNames);
List<String> orders=list.stream().map(User::getOrder).collect(Collectors.toList());
System.out.println(orders)

输出第一个：[用户1, 用户2, 用户3]
[第一位, 第二位, 第三位]

public class User {
String order;
String message;

public User(String order, String message) {
this.order = order;
this.message = message;
}
public String getOrder() {
return order;
}
public void setOrder(String order) {
this.order = order;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}

}