Web Server Setup(Ubuntu 7.10 + Tomcat 6 + MySQL + JDBC)

這幾天從家裡整裡了一台電腦，架設一台Web Server，以後會慢慢將資料轉移到這台電腦上。

規格為：

Intel Celeron 1000MHZ
512M RAM
Ubuntu 7.10
Tomcat 6.0.14

在安裝Ubuntu 7.10完後，發現並沒有安裝ssh的服務，準備apt-get時，竟然找不到相關套件，最後發現原來/etc/apt/source.list中所有的更新網站列表都被註解了，將所有#刪掉後，開始安裝openssh-server.

sudo apt-cache update
sudo apt-get install ssh

安裝完成後的ssh預設port為22，可以從/etc/ssh/sshd_config下將port改成另一個port，防止被攻擊。

Tomcat 6的安裝步驟：

1. sudo apt-get install sun-java6-jdk (取得java sdk環境)
2. sudo update-alternatives --config java (設定預設運行的java環境，選擇上一步安裝的java6)
3. 下載tomcat 6(連結)
4. sudo mv apache-tomcat-6.0.14.tar.gz /opt/ (將tomcat移至/opt/下，可自行選擇)
5. sudo tar zxvf apache-tomcat-6.0.14.tar.gz (將目錄改為tomcat6)
6. sudo vim /etc/profile (也可以加在家目錄下的.bashrc)
└ 加入此敘述export JAVA_HOME=/usr/lib/jvm/java-6-sun
7. 登出再登入
8. sudo /opt/tomcat6/bin/startup.sh
Using CATALINA_BASE: /opt/tomcat6
Using CATALINA_HOME: /opt/tomcat6
Using CATALINA_TMPDIR: /opt/tomcat6/temp
Using JRE_HOME: /usr/lib/jvm/java-6-sun
（成功訊息）
9. 從/opt/tomcat6/conf/server.xml中修改port(從8080改為80)
10. sudo /opt/tomcat6/bin/shutdown.sh
11. sudo /opt/tomcat6/bin/startup.sh
12. 連線到http://your-ip/

安裝完成後，預設的web存放位置為/opt/tomcat6/webapps/ROOT/，如需要改變預設路徑可透過/opt/tomcat6/conf/server.xml此檔改變。找到Host name並更改，如下~

<Host name="localhost" appBase="webapps"
unpackWARs="true" autoDeploy="true">
<Context path="" docBase="ROOT";
crossContext="true">
</Context>
</Host>

改為：

<Host name="localhost" appBase="/home/username/www/"
unpackWARs="true" autoDeploy="true">
<Context path="" docBase=".";
crossContext="true">
</Context>
</Host>

安裝MySQL 5.0

sudo apt-get install mysql-server (安裝完成後，會要求輸入password)

安裝JDBC

1. sudo apt-get install libmysql-java
2. sudo cp ./usr/share/java/mysql-connector-java-5.0.4.jar /opt/tomcat6/lib/ (粗體部份為Tomcat安裝路徑)
(重新啟動Tomcat將jdbc lib匯入)
3. sudo /opt/tomcat6/bin/shutdown.sh
4. sudo /opt/tomcat6/bin/startup.sh

測試JDBC(將下敘述加至*.jsp網頁中)

1.連線到mysql command
└ sudo mysql -p (-p為所輸入之root密碼)
2. 建立test資料庫
└ create database test;
3. show database
└ show databases;
4. 建立sa使用者，密碼為sa，權限為SELECT
└ GRANT SELECT ON *.* TO sa@localhost IDENTIFIED BY "sa";
5. 撰寫測試網頁
<%@ page contentType="text/html;charset=big5" %>
<%@ page import="java.util.*" %>
<%@ page import="java.io.*" %>
<%@ page import="java.sql.*" %>
<% String DB_URL = "jdbc:mysql:///test"; String DB_User = "sa"; String DB_Password = "sa"; Class.forName("com.mysql.jdbc.Driver").newInstance(); Connection con = DriverManager.getConnection(DB_URL, "sa", "sa"); %>
if(!con.isClosed())
System.out.println("Successfully connected !!" );
6. 連線到網頁進行測試。

Naming Conventions for Symbian

最近比賽告一段落了，要開始學習Symbian的學習，發現....還蠻多東西要看的，像是基本的Coding conventions更為重要啊。以下是在Symbain上Coding時需要注意的convention：

(此資料轉載於Blue119's blog)

Function Convention

• Trailing "D" indicates the deletion of an object
• Trailing "L" means function may leave
• Trailing "C" means an item is placed on the cleanup stack

-------------------------------------------

Variable Convention

• Member variables' names begin with 'i'
• Arguments' names begin with 'a'
• Automatics' (local variables) names have no initial letter, but start in lower case
• Constants' names begin with 'K'
• Global variables are usually avoided, but when used, their names begin with a capital letter.

-----------------------------------

Class Convention

'T' Classes

• Classes that don't own external objects/resources and so can be declared on the stack 'T'types contain their value.
• They do not own any external object, either directly (by pointer) or indirectly (by handle).
• they do not need a destructor to cleanup resources.
• 'T' types may be allocated either on the stack (that is locally as C++ automatic variables) or as members of other classes.
• note that the default stack size is 8KB in Symbian OS.
• Structure types mostly begin with 'T'.

'C' Classes
If a class needs to dynamically allocate any memory or own another class, it should derive, directly or indirectly, from CBase (a built-in Symbian OS class), and its class name should begin with 'C'. CBase-derived classes have the following properties:

• They are allocated on the heap (dynamically allocated) — not on the stack, and not as members of other classes.
• The allocator used for this class hierarchy initializes all member data to binary zeroes.
• They are passed by pointer, or reference, and so do not need an explicit copy constructor or assignment operator unless there is clear intention that a particular class supports copying.
• They have a virtual destructor, which is used for standard cleanup processing.
• They support two-phased construction – this will be covered later in the section.

'R' Classes
These classes are used to access system resources, for example files, via handles. The following are characteristics of ‘R’ classes:

• They contain a handle that is used to pass on requests to other objects.
• They are opened using an "Open()" function particular to the ‘R’ class, and closed using a "Close()" function particular to the class. An ‘R’ object must be closed once if it has been opened.
• They may be freely bit-wise copied.
• They have no explicit constructor, destructor, copy constructor or assignment operator.

'M' Classes
Characteristic:

• Abstract
• Pure virtual functions
• No member data

Purpose:

• define an interface

Advantage:

• reduce dependencies between classes

Rule:

• the only use of multiple inheritance
• A C class derive from one other C class and zero or more M classes

'M'classes have the following restrictions:

• They should contain no member data.
• They should not contain constructors or destructors, or overloaded operators.

'M' classes usually contain pure virtual functions that define a fully abstract interface.

轉載自Blue119's blog:Symbian Coding Conventions:Class

Applet資源取用問題

很久沒有寫Applet了，上次撰寫相關的程式應該是大學的時候吧！(約...三年前~)

最近因為比賽的關係，需要使用到Applet，只是沒想到...竟然無法在網頁上執行(使用appletviewer可以正常執行)。在網路上找尋相關的資料，發現原來我的程式有使用內部資源(像是圖片...)，而Applet因為安全性的關係，需要做簽章(Signature)的動作才可以使用。

簽章方式：

1. 安裝JDK(這樣才會有keytool、jarsigner工具)
2. 產生jar
└ jar cvf file.jar test.class ※file.jar為產生jar檔案名稱
3. 利用keytool產生key(*.crt)
└ keytool -genkey -alias appletkey ※輸入簽章相關資訊(密碼、姓名...等)
└ keytool -export -alias appletkey -file appletkey.crt ※產生crt檔，檔名為apu.crt
4. 將jar進行簽證
└ jarsigner file.jar appletkey ※會要求輸入剛剛簽章時所用的密碼
5. 轉換html
└ htmlconverter

以上步驟1、3只需要做一次就可以，之後就重覆2、4步驟即可以。

簽章完成後，發現還是無法正確使用資源，原因目前還不清楚(或許是Applet是不允許使用者直接去存取硬碟的資料，而是要直接透過網路的方式下載)。但是如果不進行簽章的動作，連透過http的方式去使用資源，也是會出現access denied的錯誤。

在使用ImageIcon的方式使用圖片，一般會像以下例子去取用資源

ImageIcon img = new ImageIcon("/picture/1.png");

這樣的情況在Applet下，是會出現access denied的錯誤，所以要改成下列的方式去取用資源

URL url = new URL("http://localhost/1.png");
ImageIcon img = new ImageIcon(url);

相關資料參考
JDK Tools and Utilities
JavaWorld

簡轉繁的利器 for Firefox

最近蠻常在逛大陸簡體的網站，發現還是不習慣看簡體字，以前在使用IE時，都有方便轉換的工具，那在Firefox上呢？

在網路上搜尋了一陣子，發現"新同文堂"這套針對Firefox用戶開發的"簡→繁"或"繁→簡"的工具。使用者可以直接在瀏覽的網頁上，使用"右鍵→新同文堂→簡轉繁"就可以將正在瀏覽的簡體網頁轉換成繁體，覺得不錯用，推薦給有使用Firefox的人嘍！

安裝方式：
‧下載"新同文堂"
‧透過Firefox選單中，"檔案→開啟檔案"的方式執行下載的xpi檔。
‧安裝後，重開Firefox即可使用。