[Resolved] Download CSV with UTF-8 handling

System generates garbage characters or question marks ??? when exporting a CSV file with Chinese character, Japanese Character..

It is okay to view the Chinese / Japanese character in notepad, but cannot be shown correctly in Excel.
It is because Excel does not handle the unicode well.

Solution
It can be solved by adding addition header (BOM, Byte order Mask) to the downloaded CSV file.

response.setContentType("application/vnd.ms-excel:UTF-8");
response.setHeader("Content-Disposition", "attachment; filename=myOutputFile.csv");

// Excel does not recongize the UTF-8, add additional header (BOM) for excel
OutputStream outputStream = response.getOutputStream();
outputStream.write(0xEF);  
outputStream.write(0xBB);
outputStream.write(0xBF);  

BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));

// Your method that generate the CSV content
writeSth(writer);

writer.flush();
writer.close();

request.getparameter returns corrupted characters

When inputs non-unicode characters (such as Japanese, Traditional Chinese),  system may returns corrupted characters during request.getParameter("XXX")

It is because the tomcat uses ISO-8859-1 as the default encoding...

Solutions:
1. By declaring page directive

<%@ page contentType="text/html;charset=UTF-8"%>

OR
2. Set the encoding before calling request.getParameter("XXX") in the page

<% 

request.setCharacterEncoding("UTF-8"); 

request.getParameter("XXX");

request.getParameter("YYY");

%>

Code Snippnet: Converting java.util.Date to java.sql.Date

 java.util.Date today = new java.util.Date();
long t = today.getTime();
java.sql.Date dt = new java.sql.Date(t);

Small Technique on using Java Decompiler in Eclipse

Here's my common use way on the Java Decompiler..

Method 1: Direct Access to the class by shortcut
1. Click Ctrl + T, and then input the class and input the class name

2. Eclipse will bring you to the class implementation.


Method 2: Direct Access to the class by Open Declaration (F3)
1. Mouse over to the corresponding class in the Java File and click F3
For example, mouse over javax.ejb.SessionBean and then  click F3

2. Eclipse will bring you to the class implementation.

Method 3: Use Java Browsing Perspective
1. Click the icon in the Red Box below to Open a new perspective

 2. Choose Java Browsing

3. You may find your class implementation as below.

Install Decompiler in Eclipse Indgio

This article will show you how to install a Java Decompiler to Eclipse.. We will use JadClipse in this example. 

JadClipse
Maintainer:	Vladimir Grishchenko, Johann Gyger
Platform:	Platform independent
Genre:	Java, Decompiler, Eclipse plug-in
License:	CPL
Languages:	English, Russian
Website:	JadClipse.sf.net

 
1. Download JAD

http://www.softpedia.com/progDownload/JAD-Download-85911.html

2. Download JADEclipse in sourceforge

http://sourceforge.net/projects/jadclipse/

3. Put the JAR to Eclipse Plugin Folder

For example: D:\eclipse_indigo\plugins\net.sf.jadclipse_3.3.0.jar

4. Start and Configure Eclipse for the JAD Plugin
In Eclipse, Click Window –> Preference –> Java –> Jadclipse

For example: 

Path to decompiler: D:\warez\JAD\jadnt158\jad.exe

Directory for temporary files: D:\tmp\Decompiler

5. Done and test
Open a file, mouse over the javax.ejb.SessionBean, click F3 to go to the class definition.

 The Decompiled Java file will be shown.

The project was not built due to "Could not delete 'XXXXXX'". Fix the problem, then try refreshing this project and building it since it may be inconsistent.

The project was not built due to  "Could not delete 'XXXXXX'". Fix the problem, then try refreshing this project and building it since it may be inconsistent.

This problem is due to the cache of the old class file in eclipse, to clean the cache..

1. Project -> Clean

2. Clean all projects

3. The error is gone.

How to avoid calling huge number of Java program

Background
When the mail server receive email, it would trigger a java program by calling a shell script.
However, as the volumne of email is large, the java program will be triggered serveral times...

Better Design