javaapplicationWeb application setup on Ubuntu VPS
题记：写这篇博客要主是加深自己对javaapplication的认识和总结实现算法时的一些验经和训教，如果有错误请指出，万分感谢。
Now there are many hosting server for people to choose to host their own apps or website. And sometimes normal web hosting can not exactly fulfil your requirements. So VPS is a good option, with VPS you can setup anything you want just like you are working in your own server.
Next I will share my experience of my java based apps/website setup, it will contains below several sections:
1. Find a good VPS;
2. Setup JDK;
3. Setup Tomcat;
4. Setup Database;
5. Setup your application;
6. Setup cron jobs;
1. Find a good VPS
Obviously, you need to choose one VPS with a reasonable price and can provide good service e.g. bandwidth this is very important for your apps/website. What you can do is find the information from internet see the feedback of those existing user. The time i chooses Atlantic.Net, as they offer $10 for the new new user, with this $10 you can almost run your apps as a trial for 2 months, and during the 2 months definitely you can see how is the service provider.
2. My website is java based, so first thing first, setup JDK
Ubuntu install and configure JDK
Ubuntu 12.04
steps:
a. download and install jdk
$sudo apt-get install openjdk-6-jdk
b. check the system JVM
$sudo update-alternatives --display java
c. install JVM
$sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-1.6.0-openjdk-i386/bin/java 60
d. update system JVM
$sudo update-alternatives –config java
e. configure environment variables
$vim /etc/profile
add below lines in the end:
export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk-i386
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$JAVA_HOME/bin:$PATH
export JAVA_HOME
export PATH
export CLASSPATH
save and reboot ubuntu
f. validate the installation
$echo $JAVA_HOME
$java -version
Note: Vi command
You need to use this for editing the configuration file
Comand mode：control the cursor move
Insert mode：only in this Insert mode you can do the editing, press Esc can go back to Comand mode
Last line mode：will save the file and leave the editing
i - insert
a - add, input from the next words
o - insert a new line and start to input
:w filename (save the file with this filename)
:wq (save and exit)
:q! (discard changes and exit)
3. Setup Tomcat
a. download apache-tomcat6,
http://archive.apache.org/dist/tomcat/tomcat-6/v6.0.28/bin/
选择Ubuntu Linux实用版本，即apache-tomcat-6.0.28.tar.gz文件，
b. 复制安装文件到/usr/local/目录下面，在控制台console输入命令，
sudo tar -zxvf apache-tomcat-6.0.28.tar.gz,
将安装包解压至apache-tomcat-6.0.28目录下，
配置tomcat的启动环境，在/etc/environment目录下添加
CATALINA_HOME="/usr/local/apache-tomcat-6.0.28"
c. console输入命令：sudo gedit /usr/local/apache-tomcat-6.0.28/bin/startup.sh，
配置startup.sh文件，添加入以下配置项，
JAVA_HOME=/usr/lib/sunJVM/JDK/jdk1.6.0_20
JRE_HOME=/usr/lib/java/jdk1.6.0_20/jre
PATH=$JAVA_HOME/bin:$JRE_HOME:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
TOMCAT_HOME=/usr/local/apache-tomcat-6.0.28
其中的JAVA_HOME等如同上文Sun JDK安装一文所示。
保存退出。
d. 进入/usr/local/apache-tomcat-6.0.28/bin/目录，
输入命令：
cd /usr/local/apache-tomcat-6.0.28/bin，
sudo ./startup.sh
启动tomcat服务器，
若涌现：
Using CATALINA_BASE: /usr/local/apache-tomcat-6.0.28
Using CATALINA_HOME: /usr/local/apache-tomcat-6.0.28
Using CATALINA_TMPDIR: /usr/local/apache-tomcat-6.0.28/temp
Using JRE_HOME: /usr/lib/sunJVM/JDK/jdk1.6.0_20
Using CLASSPATH: /usr/local/apache-tomcat-6.0.28/bin/bootstrap.jar
代码，则基本上畸形启动了，输入http://localhost:8080/查看，看看是否涌现熟悉的tomcat欢送界面。
可以用系统自带的文字浏览器w3m,
w3m的一般应用方法就是：$w3m http://localhost:8080/
C-c 停止
C-z 挂起（退出）
q 退出（需确认）
Q 退出而不确认
4. Setup database - Mysql
#apt-get install mysql-server
issue you may encounter - mysql“Access denied for user 'root'@'localhost'”
直接应用/etc/mysql/debian.cnf文件中[client]节提供的用户名和密码:
# mysql -udebian-sys-maint -p
Enter password: <输入[client]节的密码>
mysql> UPDATE user SET Password=PASSWORD('newpassword') where USER='root';
mysql> FLUSH PRIVILEGES;
mysql> quit
# mysql -uroot -p
Enter password: <输入新设的密码newpassword>
mysql> source \usr\local\test.sql;
5. setup application
put your war file to tomcat webapps directory and run tomcat
Note: jar -cvf test.war *
Issue you may encounter - com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'xyz' doesn't exist
this normally because the name is case sensitive on linux
6. Setup cron job
This will be used when there is a requirement that you need to run some cron job, e.g. update something daily to your database or sent out your application daily report
Installing Crontab From a Cron File
Instead of directly editing the crontab file, you can also add all the entries to a cron-file first. Once you have all thoese entries in the file, you can upload or install them to the cron as shown below.
ramesh@dev-db$ crontab -l
no crontab for ramesh
$ cat cron-file.txt
@yearly /home/ramesh/annual-maintenance
*/10 * * * * /home/ramesh/check-disk-space
ramesh@dev-db$ crontab cron-file.txt
ramesh@dev-db$ crontab -l
@yearly /home/ramesh/annual-maintenance
*/10 * * * * /home/ramesh/check-disk-space
Note: This will install the cron-file.txt to your crontab, which will also remove your old cron entries. So, please be careful while uploading cron entries from a cron-file.txt.
/usr/lib/jvm/java-6-openjdk/bin/javac tes.java
0 */2 * * * script.sh
#! /bin/sh
java -jar <your jar file>
@daily java -jar /usr/local/custom/cron/application.jar > /usr/local/log.log 2>&1
@daily java -jar /usr/local/custom/cron/application.jar | mail -s "cron output" youemail@gmail.com
Note: You can use the IDE tools (e.g. IntelliJ IDEA, eclipse) to package the jar file.
and this executable .jar file must contains a MANIFEST.MF file to indicate the related classpath
文章结束给大家分享下程序员的一些笑话语录：
程序员打油诗
写字楼里写字间，写字间里程序员;
程序人员写程序，又拿程序换酒钱。
酒醒只在网上坐，酒醉还来网下眠;
酒醉酒醒日复日，网上网下年复年。
但愿老死电脑间，不愿鞠躬老板前;
奔驰宝马贵者趣，公交自行程序员。
别人笑我忒疯癫，我笑自己命太贱;
不见满街漂亮妹，哪个归得程序员。
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