过滤数据

filter方法

public static void main(String[] args) throws Throwable {
    Optional<Author> author = getAuthor();
    System.out.println(author);
    Optional<Author> optional = author.filter(au -> au.getAge() > 40);
    System.out.println(optional);
}

private static Optional<Author> getAuthor() {
    //数据初始化
    Author author = new Author(1L, "蒙多", 33, "一个从菜刀中明悟哲理的祖安人", null);
    return Optional.ofNullable(author);
}

结果：

Optional[Author(id=1, name=蒙多, age=33, intro=一个从菜刀中明悟哲理的祖安人, books=null)]
Optional.empty

Process finished with exit code 0