Archive for March 2009
installing comport api in windows
comm.jar should be placed in:
%JAVA_HOME%/lib
%JAVA_HOME%/jre/lib/ext
win32com.dll should be placed in:
%JAVA_HOME%/bin
%JAVA_HOME%/jre/bin
%windir%System32
javax.comm.properties should be placed in:
%JAVA_HOME%/lib
%JAVA_HOME%/jre/lib
practice programs:
http://javamix.wordpress.com/2009/03/25/serialport-communication-using-java/
http://javamix.wordpress.com/2009/01/21/sending-sms-using-serialport-communication-api/
output comment and hiddencomment in JSP
output comment:
A comment that is sent to the client in the viewable page source.The JSP engine handles an output comment as uninterpreted HTML text, returning the comment in the HTML output sent to the client. You can see the comment by viewing the page source from your Web browser.
JSP Syntax
<!– comment [ <%= expression %> ] –>
Example 1
<!– This is a commnet sent to client on
<%= (new java.util.Date()).toLocaleString() %>
–>
Displays in the page source:
<!– This is a commnet sent to client on March 28, 2009 –>
hiddencomment
A comments that documents the JSP page but is not sent to the client. The JSP engine ignores a hidden comment, and does not process any code within hidden comment tags. A hidden comment is not sent to the client, either in the displayed JSP page or the HTML page source. The hidden comment is useful when you want to hide or “comment out” part of your JSP page.
You can use any characters in the body of the comment except the closing –%> combination. If you need to use –%> in your comment, you can escape it by typing –%\>.
JSP Syntax
<%– comment –%>
Example:
<%–
Document : commenttest
Created on : Mar 28, 2009, 11:48:27 AM
Author : vijay
–%>
<%@page contentType=”text/html” pageEncoding=”UTF-8″%>
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN”
“http://www.w3.org/TR/html4/loose.dtd”>
<html>
<head>
<meta http-equiv=”Content-Type” content=”text/html; charset=UTF-8″>
<title>JSP Page</title>
</head>
<body>
<!– this is visible comment–> comment 1
<%– this comment is not visible –%> comment 2
<h1>Hello World!</h1>
</body>
</html>
output:
when you go for browser source code it will displays the following :
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<!-- this is visible comment--> comment 1 only displays
<h1>Hello World!</h1>
</body>
</html>
Reading data from Excel sheet using JExcel API
using Java we can read the data from Excel sheets by creating type1 driver , but here
we are taking help of JExcelapi we can able to read data directly from the Excel sheets.
steps to be follow:
step 1:
download JExcel api from here
step2:
after downloading extract the zip file.
make jxl.jar available to your class path.
step 3:
create a Excel sheet with some data
step 4:
in this step we are reading data from the Excel sheet.
use the below java code:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
// this is main java program
//describes how to read from the .xls and displays
package excelsheetreading; // my package name
import java.io.File;
import java.io.IOException;
import java.util.Date;
import jxl.*;
import jxl.read.biff.BiffException;
/**
*
* @author vijay
*/
public class Main // main is my class name
{
/**
* @param args the command line arguments
*/
public static void main(String[] args) throws IOException, BiffException {
// TODO code application logic here
Workbook workbook = Workbook.getWorkbook(new File(“C:/Documents and Settings/vijay/Desktop/contacts.xls”));
// my excel sheet name is contacts, iam given the complete path.
Sheet sheet = workbook.getSheet(0); // iam reading data from the sheet1
// here iam reading the data of 1st column data up three cells
Cell a1 = sheet.getCell(0,0);
Cell b2 = sheet.getCell(0,1);
Cell c2 = sheet.getCell(0,2);
//getting the data from cells
String stringa1 = a1.getContents();
String stringb2 = b2.getContents();
String stringc2 = c2.getContents();
//printing the data
System.out.println(“a1–>”+stringa1);
System.out.println(“b2–>”+stringb2);
System.out.println(“c3–>”+stringc2);
}
}
serialport communication using Java
before going to execute this program read how to install comport api for windows
In java there is no inbuilt support to access serial or parallel ports, to over come this we are taking support of Java communication API.
after downloading the java communication api extract the folder then you can get the following…
in Commapi folder we require
comm.jar
javax.comm.properties
win32com.dll
after getting these files perform following operations….
- Copy file comm.jar in <JAVA_HOME>\jre\lib\ext
- Copy file javax.comm.properties in <JAVA_HOME>\jre\lib
- Copy file win32com.dll in <JAVA_HOME>\lib
now you can able to access the commport by Java programm.
The following example displays the available ports(serial and parallel ports) and their type:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package keyboardreader;
/**
*
* @author vijay
*/
import javax.comm.*;
import java.util.Enumeration;
public class ListPorts {
public static void main(String args[]) {
Enumeration ports = CommPortIdentifier.getPortIdentifiers();
while (ports.hasMoreElements()) {
CommPortIdentifier port = (CommPortIdentifier) ports.nextElement();
String type;
switch (port.getPortType()) {
case CommPortIdentifier.PORT_PARALLEL:
type = “Parallel”;
break;
case CommPortIdentifier.PORT_SERIAL:
type = “Serial”;
break;
default: /// Shouldn’t happen
type = “Unknown”;
break;
}
System.out.println(port.getName() + “: ” + type);
}
}
}
output is like this :
COM1: Serial
COM2: Serial
LPT1: Parallel
LPT2: Parallel
