Java 8 中的 java.util.Optional

Java 8 中的 java.util.Optional

学习了：https://blog.csdn.net/sun_promise/article/details/51362838

 

package com.stono.microservicesimpleprovideruser.controller;import com.stono.microservicesimpleprovideruser.entity.User;import java.util.Optional;public class TestOptional {    public static void main(String[] args) {
        OptionaloptionalUser = Optional.ofNullable(null);        if (optionalUser.isPresent()) {
            System.out.println("yes");
        }else {
            System.out.println("no");
        }
        OptionaloptionalUser1 = Optional.of(new User());        if (optionalUser1.isPresent()) {
            System.out.println(optionalUser1.get());
            System.out.println("yes");
        }else {
            System.out.println("no");
        }

    }
}