解答:
1.NullPointException屬於運行異常!
2.個人意見:
(1).if()判空、(2).StringUtils.isNoEmpty()
(3).java8特性判空:
判斷集合
List<User> userList = new ArrayList<User>();
userList.add(new User(1,"Tom3", "12312312"));
userList.add(new User(2,"Tom2", "34234244"));
Optional<List<User>> optional = Optional.ofNullable(userList);
optional.ifPresent(users -> {
users.stream().forEach(user -> {
System.out.println(user.getUsername());
});
});
判斷對象
Optional<User> optiona = Optional.ofNullable(new User(1,"Tom1", "80998098"));
optiona.ifPresent(user -> {
System.out.println(user.getUsername()+":"+user.getPassword());
});