Optional常用操作

@Test public void test7() { String onlineShopId = ""; // Assert.isNull(onlineShopId, "online shop id could not be null"); User user = new User(); String s = Optional.ofNullable(user).map(User::getUsername).orElse(null); Integer integer = Optional.ofNullable(user).map(User::getAge).orElse(2); // Integer integer2 = Optional.ofNullable(user).map(User::getAge).orElseThrow(() -> new IllegalArgumentException("参数异常")); System.out.println(s + "/" + integer); }