1.Get the User in a Bean

The simplest way to retrieve the currently authenticated principal is via a static call to the SecurityContextHolder:

Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
String currentPrincipalName = authentication.getName();

An improvement to this snippet is first checking if there is an authenticated user before trying to access it:

Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
if (!(authentication instanceof AnonymousAuthenticationToken)) {
    String currentUserName = authentication.getName();
    return currentUserName;
}

- 阅读剩余部分 -

Since the colors worked fine while being loggged in directly, I just un-uncommented the line force_color_prompt=yes in the file ~/.bashrc, that gave me colors over ssh, too:

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
force_color_prompt=yes

(Ubuntu 18.04 LTS)

https://askubuntu.com/questions/16336/how-to-get-coloured-terminal-over-ssh

1. Install sudo. Some installations do not come with sudo installed. If your does not, install sudo with apt.

# apt install sudo

2. Create a new user account with the adduser command. Use a strong password for the new user. You can enter values for the user information, or press ENTER to leave those fields blank.

# adduser example_user
Adding user `example_user' ...
Adding new group `example_user' (1001) ...
Adding new user `example_user' (1001) with group `example_user' ...
Creating home directory `/home/example_user' ...
Copying files from `/etc/skel' ...
New password:
Retype new password:
passwd: password updated successfully
Changing the user information for example_user
Enter the new value, or press ENTER for the default
        Full Name []: Example User
        Room Number []:
        Work Phone []:
        Home Phone []:
        Other []:
Is the information correct? [Y/n] y

3. Add the new user to the sudo group.

# adduser example_user sudo

4. Test by switching to the new user.

# su - example_user

Verify you are the new user with whoami, then test sudo access with sudo whoami, which should return root.

$ whoami
example_user
$ sudo whoami
[sudo] password for example_user:
root

How to use Sudo on a Vultr Cloud Server

单一的 zh 和 zh-CN 均属于废弃用法。

问题主要在于，zh 现在不是语言code了，而是macrolang，能作为语言code的是cmn（国语）、yue（粤语）、wuu（吴语）等。我通常建议写成 zh-cmn 而不是光写 cmn，主要是考虑兼容性（至少可匹配 zh），有不少软件和框架还没有据此更新。

zh-CN 的问题还在于，其实多数情况下标记的是简体中文，但是不恰当的使用了地区，这导致同样用简体中文的 zh-SG（新加坡）等无法匹配。更典型的是 zh-TW 和 zh-HK。所以其实应该使用 zh-Hans / zh-Hant 来表示简体和繁体。那么完整的写法就是 zh-cmn-Hans，表示简体中文书写的普通话/国语。一般而言没有必要加地区代码，除非要表示地区特异性，一般是词汇不一样（比如维基百科的大陆简体和新马简体）。

如何标记的例子：

1. 简体中文页面：html lang=zh-cmn-Hans
2. 繁体中文页面：html lang=zh-cmn-Hant
3. 英语页面：html lang=en

作者：贺师俊
链接：https://www.zhihu.com/question/20797118/answer/16809331
来源：知乎
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

This is known issue in Hibernate, see https://hibernate.atlassian.net/browse/HHH-8805

Solution is to add @org.hibernate.annotations.ForeignKey(name = "none") on the mapped side.

class Parent {

  @OneToMany(mappedBy="parent", cascade=CascadeType.ALL, orphanRemoval=true)
  @OrderColumn(name="childIndex")
  @org.hibernate.annotations.ForeignKey(name = "none")
  public List<Child> getChildren() {
    return children;
  }

}

Note: Prefer the JPA 2.1 introduced javax.persistence.ForeignKey instead. The native annotation is deprecated.

answerd by Bustanil Arifin and sophros How do I disable Hibernate foreign key constraint on a bidirectional association?