[Troubleshooting] Apache HTTP Server cannot start

[Scenario]
有些時候，可能因為改了某些設定，如修改httpd.conf之後無法正常啟動

[Solution]
此時你可以執行Test Configuration來看錯誤訊息
開始→程式集→Apache HTTP Server→Configure Apache Server→Test Configuration

[Info] Struts+Spring+iBatis的輕量級J2EE開發

Struts+Spring+iBatis的輕量級J2EE開發

[Info] Comparing Web Frameworks Struts, Spring MVC, WebWork, Tapestry & JSF

File Type:PDF
Comparing Web Frameworks Struts, Spring MVC, WebWork, Tapestry & JSF

[Info] Two Approaches to Open New Window

按icon與用File/New/Window的動作不一樣, 按Icon的話, 是起一個新的session, 後者的話, 是share同一個session
這裡有一個link: from JavaWorld
除此之外, 用icon, 與用File/New/Window, 後者可能會有一些問題, 可參考此link:experts-exchange

[Troubleshooting] SQLException: IO 異常: The Network Adapter could not establish the connection

錯誤訊息
SQLException: IO 異常: The Network Adapter could not establish the connection

成因
1. 資料庫沒有開啟, 所以無法連接上
2. 因為防火牆的原因, 該台連不上DBMS Server, 可先ping看看可否ping的到, ex. ping xxx.xxx.xxx.xxx 1521

[Troubleshooting] 530 Sorry, no ANONYMOUS access allowed

Scenario
用Server-U架起一個FTP Server，建立username=ftp, password=ftptest
此時用其他的ftp連線工具連線的時候，會出現此錯誤訊息: 530 Sorry, no ANONYMOUS access allowed

原因
因為ftp是保留字，不可以將其當成username，要將username改成其他名字即可

[Info] JavaMail

Spring Framework also provide an abstract layer for JavaMail.
Here has a reference link:
Sending Email with Spring mail abstraction layer

Here has sample code which write by me:

package albert.guo.util;



import java.io.File;

import java.util.ArrayList;

import java.util.HashMap;



import javax.mail.MessagingException;

import javax.mail.internet.MimeMessage;



import org.springframework.mail.SimpleMailMessage;

import org.springframework.mail.javamail.JavaMailSenderImpl;

import org.springframework.mail.javamail.MimeMessageHelper;



/**

*

* @author Albert

*

*/

public class MailUtil {



private String addr[];

private String subject;

private String text;

private String host;

private String filepath;

private String filename;

private ArrayList fileList;



public MailUtil(String iAddr[], String iSubject, String iText, String iHost){

this.addr = iAddr;

this.subject = iSubject;

this.text = iText;

this.host = iHost;

}



public MailUtil(String iAddr[], String iSubject, String iText, String iHost,

ArrayList iFileList){

this.addr = iAddr;

this.subject = iSubject;

this.text = iText;

this.host = iHost;

this.fileList = iFileList;

}



/*

* 發送mail(不含附加檔案)

*/

public void sendMsg(){

SimpleMailMessage msg = new SimpleMailMessage();

msg.setTo(this.addr);

msg.setSubject(this.subject);

msg.setText(this.text);



JavaMailSenderImpl mailSender = new JavaMailSenderImpl();

mailSender.setHost(this.host);

mailSender.send(msg);

}



/*

* 發送mail(含附加檔案)

*/

public void sendMsgAndAttachment(){

JavaMailSenderImpl sender = new JavaMailSenderImpl();

sender.setHost(this.host);



MimeMessage message = sender.createMimeMessage();



try {

//use the true flag to indicate you need a multipart message

MimeMessageHelper helper = new MimeMessageHelper(message, true);

helper.setTo(this.addr);

helper.setSubject(this.subject);

helper.setText(this.text);



for(int i=0; i<this.fileList.size(); i++){

HashMap attachment = (HashMap)fileList.get(i);

String filepath = (String)attachment.get("filepath");

String filename = (String)attachment.get("filename");

helper.addAttachment(filename, new File(filepath+filename));

}

sender.send(message);

} catch (MessagingException e) {

e.printStackTrace();

}

}



public static void main(String[] args) {

String addr[] = new String [] {"albertg@systex.com.tw"};

//MailUtil mailUtil = new MailUtil(addr, "標題", "內容\n啦啦啦", "mail.systex.com.tw");

//mailUtil.sendMsg();

ArrayList list = new ArrayList();

HashMap hm1 = new HashMap();

hm1.put("filepath", "C:/");

hm1.put("filename","test.doc");

HashMap hm2 = new HashMap();

hm2.put("filepath", "C:/");

hm2.put("filename", "LiveABC.Log");

list.add(hm1);

list.add(hm2);

MailUtil mailUtil = new MailUtil(addr, "標題", "內容\n啦啦啦", "mail.systex.com.tw",
list);

mailUtil.sendMsgAndAttachment();

}



}

　

[Info] AJAX

http://www.luar.com.hk/flashbook/archives/001129.php

[Troubleshoot] JDBC Connection Leak

資料庫連線洩漏原因

在JSP中設定ErrorPage時，發生跳轉，來不及關閉連線
程式的錯誤處理非在finally區塊關閉連線


緩解方式

設定InactiveConnectionTimeoutSeconds時間
最終一定要修復程式中的問題

[Info] 如何在IE中直接打開WORD等文件

Q.
如何在一个WEB APPLICATION中打開WORD，EXCEL等類型的文件?

ans.

為了讓能在IE流覽器中自動打開的設置：需要在WEB.XML中進行如下的設置：在WEB.XML中添加<mime-mapping>,其中:

<extension>:
文件的副檔名

<mime-type>:
除了該類型檔的可執行檔,同WINDOW註冊表中的

/HKEY_CLASSES_ROOT下該類檔的Content
Type 的值一樣.

如能在IE中自動打開DOC，XLS，PDF檔的配置如下:

<?xml version="1.0" ?>

<!DOCTYPE web-app PUBLIC "-//Sun
Microsystems, Inc.//DTD Web Application 1.2//EN"

"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">

<web-app>

<mime-mapping>

<extension>doc</extension>

<mime-type>application/msword</mime-type>

</mime-mapping>

<mime-mapping>

<extension>xls</extension>

<mime-type>application/msexcel</mime-type>

</mime-mapping>

<mime-mapping>

<extension>pdf</extension>

<mime-type>application/pdf</mime-type>

</mime-mapping>

</web-app>

[Troubleshooting] Too many open files

Q.

<2005/9/27 上午09時32分13秒 GMT+08:00> <Critical> <WebLogicServer> <BEA-000204>
<Failed to listen on port 7001, failure count: 2,204, failing for 31,398
seconds, java.net.SocketException: Too many open files>

　

A.
大致上來說，這個問題有可能導因於OS的設定、應用程式在處理IO的時候，沒有正確關閉stream，以致於這些讀取檔案系統的stream一直處於開啟的狀態，最後就把系統所允許的file數給耗盡了。另外，如果在應用程式中開啟了一些socket，沒有正確關閉，也會發生相同的狀況 。這些關閉IO、socket的指令，一定要放在finally的區塊裡面，以確保即使發生exception，還是會被執行到。

We may increase the rlimit for a process by increasing the rlim_fd_max value (e.g. set rlim_fd_max = 4096) on /etc/system and enlarge the default open file number with ulimit -n 4096.
However, if we still find the open file limit for the java process that hosts WebLogic Server cannot excceed 1024,
please edit '${WL_HOME}/common/bin/commEnv.sh'.
COMMENT OUT the last line and add an ulimit statement (e.g. ulimit -n 8192)in the startup scripts.//resetFd

[Troubleshooting] Cannot Find WebappContextListener

Q.為什麼我在佈署我的程式的時候，一直出現無法找到com.bea.wlw.runtime.core.servlet.WebappContextListener此錯誤訊息

Ans.此成因在於工程師可能採用workshop IDE tool來進行ap的開發，然後要部署到basic weblogic server此template，所以會有找不到此class的情形
此時，你只要把web.xml裡頭的此段拿掉即可，此為Workshop IDE Tool自行加上的

<listener>

<listener-class>

com.bea.wlw.runtime.core.servlet.WebappContextListener

</listener-class>

</listener>

[Info] JDK vs. J2SDK

JDK其實是J2SDK以前的名字。

JDK 1.0 版於 1996 年初release，JDK 1.1 版於 1997 年初release，JDK 1.2 版於 1998 年底release。基於市場行銷的考量，Sun 在 JDK 1.2 版release後將 Java 改名為「Java 2」，將 JDK 改名為「Java 2 Software Development Kit（以下簡稱 J2SDK）」。

然而，雖然改了名字，但是其內在還是沒有變化，其仍舊包含了Java Development kit(JDK)、Java Runtime Environment(JRE)，這兩者的差異是：JDK是for programmer所使用，JRE則是提供Java程式運行的環境。

[Info] 檢查有無安裝JVM

http://java.com/zh_tw/download/windows_automatic.jsp

[Troubleshooing] BEA-101083

exception message
####<2005/9/12 下午07時52分46秒 GMT+08:00> <Error> <HTTP> <rx2620e1> <uat01>
<ExecuteThread: '1' for queue: 'weblogic.socket.Muxer'> <<WLS Kernel>> <> <BEA-101083> <Connection failure.

java.lang.Throwable: Error in poll for fd=328, revents=8

at weblogic.socket.PosixSocketMuxer.processSockets(PosixSocketMuxer.java:128)

at weblogic.socket.SocketReaderRequest.execute(SocketReaderRequest.java:32)

at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:219)

at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:178)

>

reference link

DESCRIPTION:
Enhancement Request.
Running WLS 8.1 SP2 on HPUX11i.

Customer has requested an enhancement.
The customer wants to suppress (not print) the following error:

<May 25, 2004 10:05:11 PM GMT> <Error> <HTTP> <BEA-101083>

<Connection failure.java.net.SocketException: Error in poll for fd=81, revents=8

at weblogic.socket.PosixSocketMuxer.processSockets(PosixSocketMuxer.java:128)

at weblogic.socket.SocketReaderRequest.execute(SocketReaderRequest.java:32)

at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:197)

at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:170)

This message unnecessarily fills up their log.

This exception can be thrown if their client / browser initiated multiple requests (sockets were opened) and the client connections were closed before WLS could process the requests (and could not write to the stream any more).

This is a harmless message (unnecessary message).

[Info] Object-Relational Mapping with SQLMaps

http://www.onjava.com/lpt/a/5598

[troubleshooting] [EJB:010207]License validation not passed for 2.0

exception msg
Module Name: QueueTransportEJB, Error: Exception preparing module: EJBModule(QueueTransportEJB,status=NEW)
Unable to deploy EJB: /bea/weblogic81/server/lib/QueueTransportEJB.jar from QueueTransportEJB.jar:
java.lang.Exception: [EJB:010207]License validation not passed for 2.0.'

因為客戶的版本是express的版本(不含EJB Container)，但是其在create domain的時候，使用sample此template(有EJB的code)，改採server此temaplte來create即可

[How-To] memory allocation for WLS

關於memory allocation，你要加在此行(位於script file的下半部)：
%JAVA_HOME%\bin\java %JAVA_VM% %MEM_ARGS% %JAVA_OPTIONS% -ms512m -mx512m -Dweblogic.Name=%SERVER_NAME% -Dweblogic.ProductionModeEnabled=%PRODUCTION_MODE% -Djava.security.policy="%WL_HOME%\server\lib\weblogic.policy" weblogic.Server

512的地方可以replace成你想要的memory的量

[How-To] Capacity Estination

http://www.spec.org/

http://e-docs.bea.com/wls/docs81/capplan/capbase.html#1055436

[info] Linux Tuning Parameters Tuning

http://e-docs.bea.com/wls/docs81/perform/HWTuning.html#1121228