E45: 'readonly' option is set (add ! to override)

该错误为当前用户没有权限对文件作修改

有三种可能：

1 . 该错误为当前用户没有权限对文件作修改,你有权限修改文件吗？如果有root权限，可以:wq! 强行保存退出；然后更改权限了在来编辑文本。

2 . 该文件在上次编辑时没有正确保存退出，那么多半在打开文件时会出现这样一种情况。

   E325: ATTENTION
    Found a swap file by the name ".jun1.txt.swp"
              owned by: wasadmin   dated: Tue Nov 29 14:31:30 2016
             file name: //文件路径
              modified: no
             user name: wasadmin   host name: B2C-WAP-API-2
            process ID: 9278 (still running)
    While opening file "application.properties"
                 dated: Tue Nov 29 12:48:05 2016
     
(1) Another program may be editing the same file.
    If this is the case, be careful not to end up with two
    different instances of the same file when making changes.
    Quit, or continue with caution.
 
(2) An edit session for this file crashed.
    If this is the case, use ":recover" or "vim -r .jun1.txt"
    to recover the changes (see ":help recovery").
    If you did this already, delete the swap file ".jun1.txt.swp"
    to avoid this message.
 
Swap file ".jun1.txt.swp" already exists!
[O]pen Read-Only, (E)dit anyway, (R)ecover, (Q)uit, (A)bort:

这是你非正常退出系统给你保存了一个“.swp”的副本，是个隐藏文件。

解决办法：做好需要更改部分的备份，退出编辑该文件，使用 ls -a查看所有文件，删除“.swp”副本文件，就可以了。

3.该文件是未关闭状态；

解决办法：

1、按Esc 
2、输入：set noreadonly 
3、即可按正常途径保存:wq