[ORACLE] Get size in BYTE of a column

LENGTHB(COLUMN_NAME)

謝謝有為的中年人<(_ _)>
ref: KB-在Oracle中直接取得中文字串長度

Change File Permission via ftpd

方案一，上傳檔案才chmod修改檔案權限
In Windows command line:

ftp> chmod
Invalid command.

Do it by "quote" command:

ftp> quote
Command line to send site chmod 666 filename.txt
200 CHMOD command successful.

缺點:
FTP裡下chmod指令無法使用萬用字元(*, wildcard)，也無法使用 -R flag。
好不容易知道怎麼透過FTP下chmod了... 不實用

Using Apache Commons Net 3.2 API in java:

   1:  //using public int sendCommand(String command, String args)

   2:  //實在不知道那些字要放在command, 哪些字要放在args, try了好幾次

   3:  //TEST#1:

   4:  FTPClient.sendCommand("quote", "site chmod 666 *");

   5:  //command result=500 'QUOTE site chmod 666 *': command not understood.

   6:   

   7:  //TEST#2:

   8:  FTPClient.sendCommand("quote site chmod", "666 *");

   9:  //command result=500 'QUOTE site chmod 666 *': command not understood.

.....試了N百個組合都不認得, go die
還有error message回傳的指令都寫大寫也很奇怪.. unix大小寫有差啊，我要小寫!!

最後讀了public int sendCommand(int command, String args)方法才知道他根本就沒提供quote這個指令OTZ||| 從FTPCommand看起來，"SITE"是最有可能會動的指令:

   1:  //TEST#3:

   2:  FTPClient.sendCommand("site", "chmod 666 *");

   3:  //command result=550 *: A file or directory in the path name does not exist.

........ 透過程式來做也一樣，*不能用，再度遭受打擊OTZ|||

   1:  //TEST#4:

   2:  FTPClient.sendCommand("site", "chmod 666 filename.txt");

   3:  //command result=200 CHMOD command successful.

一次只能改一個檔案也太讓人不爽了。所以先上傳檔案才修改檔案權限的方案透過FTP不work。

方案二，登入FTP後先下umask指令來控制檔案權限
In Windows command line:

ftp> quote
Command line to send site umask 000
200 UMASK set to 000 (was 007)

Using Apache Commons Net 3.2 API in java:

   1:  //TEST#5:

   2:  FTPClient.sendCommand("site", "umask 002");

   3:  //command result=200 UMASK set to 002 (was 007)

特別提醒透過下umask方法目前測起來只對FTP有用，SFTP應該無效。
又是另一項作業..

Ref:

1. [API] FTP.sendCommand(String, String)
2. [API] FTPCommand class

Using Editable JComboBox with KeyEvent

//The following code wont’t work
JComboBox jcb1 = new JComboBox();
jcb1.setEditable(true);
jcb1.addKeyListener(aKeyEventObject);

//Correct: KeyEvent should be added to JComboBox.getEditor().getEditorComponent()
JComboBox jcb2 = new JComboBox();
jcb2.setEditable(true);
jcb2.getEditor().getEditorComponent().addListerer(aKeyEventObject);

Calling to JComboBox.getEditor().getEditorComponent() will return a JTextField that is used for editing the comboBox’s text.

And if at the same moment you want to get the filling text:

//The following code won’t work(return null)
String s = jcb2.getSelectedItem().toString();

//Correct:
String s = ((JTextComponent)jcb.getEditor().getEditorComponent()).getText();