Tech-lona

Inserting & in oracle

2009-04-13T18:30:00.000+08:00

If there are any & symbol in your sql insert query value, replace it with &'||'. (In case if the query fails to run)

The & will be considered as beginning of variable name in Oracle SQL.

Note: This is only if the & symbol is inside quotes.

Eg:

Insert into temp values(2.’me&u’); è Insert into temp values(2.’me&’||’u’);

Searching inside the Oracle Functions/Packages/Procedures

2009-03-31T19:00:00.004+08:00

To search a text inside a oracle database function or package, We can use this query

select * from USER_SOURCE where upper(TEXT) like '%search text%'

USER_SOURCE describes the text source of the stored objects owned by the current user. Its columns (except for OWNER) are the same as those in "ALL_SOURCE".
- http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/statviews_4436.htm

@ and " are swapped?

2008-11-10T11:14:00.001+08:00

Oh God. This is a terrible problem i had.

Whenever i pressed @ key in laptop, " came as output. and vice versa.

But the Solution was damn simple.

Someone changed the Keyboard country setting to UK, Just change it to US. Thats all.

Number restriction in textbox using javascript

2008-11-04T10:48:00.002+08:00

I have a developed this simple javascript to allow user to key in only numerics and dot(for decimals).

function verify(e)
{
var zero=48;
var nine=57;
var dot=46;
if((e.keyCode==dot)||(e.keyCode>=zero && e.keyCode<=nine)){
return true;
}
return false;
}

Best example for Javamail

2008-10-31T16:51:00.001+08:00

I have found a wonderful sample of javamail in here http://www.rgagnon.com/javadetails/java-0321.html

Apache Service not running in port 80

2008-10-30T12:05:00.002+08:00

I have been trying to learn php and MySQL stuff for hosting my own website. I will write a separate post on how to configure and initial settings.

But main problem all will encounter will be the port 80 already running.

If any other service runs in port 80, then the apache server service wont start. It will keep begging you to clean port or change port.

The one simple solution is to change the listen port in the httpd.conf
Change Listen 80 to Listen 90. Here the port 90 can be anyother free port.

If not and you desperately wanted to change the port, then you need to scan all your ports. Check which process is using port 80 and kill it.

The one of the best freeware command prompt port scanner i use is fport.

Use it to find the port, and stop the process. Continue with your port 80. :)

FileUpload in JSP

2008-10-17T11:16:00.005+08:00

Its been so long since i last blogged.
This time i am coming up with how to upload files in jsp.

The first and formost thing before doing this is to have the necessary framework to do this uploading.

You can use Apache Common FileUpload or com.oreilly.servlet.

Here i have used the second one.

In the jsp, the form should have the multipart encoding. To do this, please follow the following HTML snippet.

<form action="../AddCandidateServlet" method="post" enctype="multipart/form-data">

But if you do this, then the normail request.getParameter(str) will not be capable of reading the file or other input values from the particular form, so in order to do that specific task, we need to use the external frameworks.

The following example doPost method, reads all parameters and values. Also it stores the file in the specified location.

The following code is not my code, its been extracted from the site.

/*
* DemoParserUploadServlet.java
*
* Example servlet to handle file uploads using MultipartParser for
* decoding the incoming multipart/form-data stream
*/

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

import com.oreilly.servlet.multipart.*;

public class DemoParserUploadServlet extends HttpServlet {
private File dir;

public void init(ServletConfig config) throws ServletException {
super.init(config);
// Read the uploadDir from the servlet parameters
String dirName; //= config.getInitParameter("uploadDir");
dirName="C:\\Program Files\\Apache Group\\Tomcat 4.1\\webapps\\examples\\WEB-INF\\classes\\cal";
//if (dirName == null) {
// throw new ServletException("Please supply uploadDir parameter");
//}
dir = new File(dirName);
if (! dir.isDirectory()) {
throw new ServletException("Supplied uploadDir " + dirName +
" is invalid");
}
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
PrintWriter out = response.getWriter();
response.setContentType("text/plain");
out.println("Demo Parser Upload Servlet");
if(false)
{

try {
MultipartParser mp = new MultipartParser(request, 1*1024*1024); // 10MB
Part part;
while ((part = mp.readNextPart()) != null) {
String name = part.getName();
if (part.isParam()) {
// it's a parameter part
ParamPart paramPart = (ParamPart) part;
String value = paramPart.getStringValue();
out.println("param; name=" + name + ", value=" + value);
}
else if (part.isFile()) {
// it's a file part
FilePart filePart = (FilePart) part;
String fileName = filePart.getFileName();
if (fileName != null) {
// the part actually contained a file
long size = filePart.writeTo(dir);
out.println("file; name=" + name + "; filename=" + fileName +
", filePath=" + filePart.getFilePath() +
", content type=" + filePart.getContentType() +
", size=" + size);

}
else {
// the field did not contain a file
out.println("file; name=" + name + "; EMPTY");
}
out.flush();
}
}
}
catch (IOException lEx) {
this.getServletContext().log(lEx, "error reading or saving file");
}
}

// If the next two lines are giving errors, you can comment it. But you will not be able to some other works with it.
CommandProcessor cp=new CommandProcessor();
cp.process(request,response);
HttpSession session=request.getSession();
String fname=(String)session.getAttribute("FILENAME");
out.println("returned from cp"+fname);
}
}

A Servlet Filter for authentication

2008-08-27T19:14:00.000+08:00

import java.io.IOException;
import java.util.ArrayList;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import my.com.lhdn.cms.security.base.Globals;
import my.com.lhdn.cms.security.base.util.UserLevelBean;

import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class AuthenticationFilter implements Filter {
private static Log log = LogFactory.getLog(AuthenticationFilter.class);

private FilterConfig filterConfig = null;

private static ArrayList bypassURLs = null;

public AuthenticationFilter() {
System.out.println("--AuthenticationFilter--");
}

/**
* Called by the web container to indicate to a filter that it is being
* placed into service.
*/
public void init(FilterConfig filterConfig) {
this.filterConfig = filterConfig;

log.info("AuthenticationFilter init, now monitoring each request.");
}

/**
* The doFilter method of the Filter is called by the container each time a
* request/response pair is passed through the chain due to a client request
* for a resource at the end of the chain.
*/
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {

HttpServletRequest httpRequest = null;
HttpServletResponse httpResponse = null;

try {
if (request instanceof HttpServletRequest
&& response instanceof HttpServletResponse) {
httpRequest = ((HttpServletRequest) request);
httpResponse = (HttpServletResponse) response;
System.err.println("Entering into " + httpRequest.getRequestURI().toString());

HttpSession session = httpRequest.getSession(false);
String tmpurl = null;
if (session != null) {
if (session.getAttribute(Globals.SESSION_USER) != null) {
if (VALID_USER) {
return;
}
} else {
session.invalidate();
httpResponse.sendRedirect(httpRequest.getContextPath()+"/login.do");
//GO TO LOGIN PAGE SINCE NOT AUTHENTICATED
return;
}

} else {
//GO TO LOGIN PAGE SINCE NO SESSION INITIATED
httpResponse.sendRedirect(httpRequest.getContextPath()+"/login.do");
return;

}
chain.doFilter(request, response);

return;
}
} catch (Exception ex) {
if (log.isErrorEnabled())
log.error(ex);
throw new ServletException(ex);
} finally {
System.err.println("Leaving " + httpRequest.getRequestURI().toString());
}
}

/**
* Called by the web container to indicate to a filter that it is being
* taken out of service.
*/
public void destroy() {
filterConfig = null;
}
}

A Password oneway encryption utility

2008-08-27T19:07:00.000+08:00

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.w3c.tools.codec.Base64FormatException;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class PasswordUtil {
private static PasswordUtil instance = null;

public static PasswordUtil getInstance() {
if (instance == null) {
instance = new PasswordUtil();
}

return instance;
}

public synchronized String encrypt(String password) {
MessageDigest messageDigest = null;

try {
messageDigest = MessageDigest.getInstance("SHA-1");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}

try {
messageDigest.update(password.getBytes("UTF-8"));
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}

byte raw[] = messageDigest.digest();
String hash = (new BASE64Encoder()).encode(raw);
return hash;
}

public boolean verifyPassword(String passwordBytes, String passwordHash)
throws NoSuchAlgorithmException {
return encrypt(passwordBytes).equals(passwordHash);
}

}

Unicode in jsp

2008-08-27T18:59:00.002+08:00

Using unicode in jsp or java files under influence of any IDE like RAD can be easier.

Before pasting your unicode data into the jsp,java or data file in RAD, make the file encoding into utf-8. You can do this by

Select file in package explorer
Right click and choose Properties
Choose the Other option in the Text-Encoding.
From the list choose UTF-8

Even though you specify the metadata content type tag as UTF-8, you still need to do the same thing using

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

And here you go, your யூனிகோட்(Unicode) displays fine in the screen :)

DB2 - SCHEMA - Query

2008-08-27T18:54:00.003+08:00

In DB2, normal select query like the one below, may not work properly

SELECT * FROM table;

In that cases, We need to specify the schema name to query the table.

SELECT * FROM schema.table;

Alternatively, for a query session, we can set the schema beforehand using,

SET SCHEMA schema_name;

Now this query will work fine :)

SELECT * FROM table;

JDBC connection from Excel sheet

2008-07-23T18:36:00.001+08:00

This code snippet converts the Excel file into a virtual database with the sheets as tables. No need to create and DSN in the system is the plus of this snippet.

String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
Class.forName(driver);
Connection connection = DriverManager.getConnection(
"jdbc:odbc:Driver={Microsoft Excel Driver (*.xls)};DBQ=F:\\Kishore\\exam.xls;
DriverID=22;READONLY=false","", "");

You can use the following query to get the values from the sheets.
select * from [Sheet1$]

The first row is considered as the column as usual. Here the empty columns will not be considered.

But there is a disadvantage in this. If you encounter let me know, i will give the solution :)

Select in HTML

2008-07-23T15:34:00.004+08:00

This is an example to have option group and different styles inside a select box.
Check out. Enjoy

Check out the view source.

<select>

 <option selected="selected">