今天总结了下JDK中排序的方法,包括JDK8中强大的lambda表达式及函数式接口运用,不废话,请看下面示例。
public class Test {
public static void main(String[] args) {
List<User> list = initList();
// jdk8之前的排序
(list, new Comparator<User>() {
@Override
public int compare(User o1, User o2) {
return ().compareTo(());
}
});
// jdk8 lambda排序,带参数类型
list = initList();
((User u1, User u2) -> ().compareTo(()));
(::println);
();
// jdk8 lambda排序,不带参数类型
list = initList();
((u1, u2) -> ().compareTo(()));
(::println);
();
// jdk8 排序,User类静态方法引用
list = initList();
(User::compareAge);
(::println);
();
// jdk8 升序排序,Comparator提供的静态方法
list = initList();
(list, (User::getAge));
(::println);
();
// jdk8 降序排序,Comparator提供的静态方法
list = initList();
(list, (User::getAge).reversed());
(::println);
();
// jdk8 组合排序,Comparator提供的静态方法,先按年纪排序,年纪相同的按名称排序
list = initList();
(list, (User::getAge).thenComparing(User::getName));
(::println);
}
private static List<User> initList() {
List<User> list = new ArrayList<>();
(new User("lisa", 23));
(new User("tom", 11));
(new User("john", 16));
(new User("jennis", 26));
(new User("tin", 26));
(new User("army", 26));
(new User("mack", 19));
(new User("jobs", 65));
return list;
}
}
看完有没有觉得很惊艳,简直屌炸天,Lumbda表达式+函数式接口还有更多强大的应用下回再做个专题介绍。