// Creation of custom tag using BodyTagSupport example in this example we will take user gross salary,tax allowance and tax percentage and caliculate the net salary using tag lib
Step 1 :- Create a dynamic web project
Step 2 :- Create a html page were we can take the inputs from user as given bellow
//income.html
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/1999/xhtml
http://www.w3.org/2002/08/xhtml/xhtml1-strict.xsd">
<head><title>Input Income & Tax Details</title></head>
<body>
<h1>Enter Income & Tax Figures</h1>
<form action="taxation.jspx">//transferring control to taxation.jspx
<table>
<tr>//user enterring details
<td>Enter gross income:</td>
<td><input type="text" name="gross" /></td>
</tr>
<tr>
<td>Enter tax allowance:</td>
<td><input type="text" name="allowance" /></td>
</tr>
<tr>
<td>Enter tax rate (percentage):</td>
<td><input type="text" name="rate" /></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="Calculate Net Income" /></td>
</tr>
</table>
</form>
</body>
</html>
Step 3 :- Now create the taxation.jspx were we will be having our tag used to caliculate the result salary
<html xmlns:mytags="http://www.xyz.com/taglibs/mytags"
xmlns:jsp="http://java.sun.com/JSP/Page">//declaring our tag in xhtml format if you want you can follow jsp format
<jsp:output omit-xml-declaration="true" />
<jsp:directive.page contentType="text/html" />
<head><title>Taxation, Taxation, Taxation</title></head>
<body>
<h1>Calculated Net Income</h1>
<p>My net income is:
<mytags:netincome grossIncome="${param.gross}"
allowance="${param.allowance}"
taxRate="${param.rate}"
currency="GBP" />//our custom tag
</p>
</body>
</html>
Step 4 :- Now create the myTags.tld wnder the webcontent by creating a folder name tags and place in it
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<tlib-version>1.0</tlib-version>
<short-name>MyTagLib</short-name>
<uri>http://www.osborne.com/mytags.tld</uri>
<tag>
<name>netincome</name>//our tagname implementation
<tag-class>web.prac.TaxationTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>grossIncome</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>allowance</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>taxRate</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>currency</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
Step 5 :- Now create the tag implementation class
package web.prac;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
public class TaxationTag extends BodyTagSupport {
private String grossIncome;
private String taxRate;
private String allowance;
private String currency;
public void setAllowance(String allowance) {
this.allowance = allowance;
}
public void setGrossIncome(String grossIncome) {
this.grossIncome = grossIncome;
}
public void setTaxRate(String taxRate) {
this.taxRate = taxRate;
}
public void setCurrency(String currency) {
this.currency = currency;
}
public int doStartTag() throws JspException {
JspWriter out = pageContext.getOut();
double gross;
double rate;
double allow;
try {
/* Convert string input to numerics */
gross = Double.parseDouble(grossIncome);
rate = Double.parseDouble(taxRate);
allow = Double.parseDouble(allowance);
} catch (NumberFormatException nfe) {
try {
out.write("Bad Input Figures");
} catch (IOException ioe) {
ioe.printStackTrace();
}
return super.doStartTag();
}
double taxToPay = ((gross - allow) * rate / 100);
double net = (gross - taxToPay);
NumberFormat nf = NumberFormat.getInstance();
Currency c = Currency.getInstance(currency);
nf.setCurrency(c);
nf.setMinimumFractionDigits(c.getDefaultFractionDigits());
nf.setMaximumFractionDigits(c.getDefaultFractionDigits());
try {
out.print(c.getSymbol() + nf.format(net));
} catch (IOException e) {
e.printStackTrace();
}
return super.doStartTag();
}
}
Step 5 :- Now map it in web.xml
<?xml version="1.0" ?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<jsp-config>
<taglib>//declare our tag lib
<taglib-uri>http://www.x.y.z.com/taglibs/mytags</taglib-uri>
<taglib-location>/WEB-INF/tags/mytags.tld</taglib-location>
</taglib>
</jsp-config>
</web-app>
Step 6 :- Clean build and run the project
output :-Enter values an submit it
Step 1 :- Create a dynamic web project
Step 2 :- Create a html page were we can take the inputs from user as given bellow
//income.html
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/1999/xhtml
http://www.w3.org/2002/08/xhtml/xhtml1-strict.xsd">
<head><title>Input Income & Tax Details</title></head>
<body>
<h1>Enter Income & Tax Figures</h1>
<form action="taxation.jspx">//transferring control to taxation.jspx
<table>
<tr>//user enterring details
<td>Enter gross income:</td>
<td><input type="text" name="gross" /></td>
</tr>
<tr>
<td>Enter tax allowance:</td>
<td><input type="text" name="allowance" /></td>
</tr>
<tr>
<td>Enter tax rate (percentage):</td>
<td><input type="text" name="rate" /></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="Calculate Net Income" /></td>
</tr>
</table>
</form>
</body>
</html>
Step 3 :- Now create the taxation.jspx were we will be having our tag used to caliculate the result salary
<html xmlns:mytags="http://www.xyz.com/taglibs/mytags"
xmlns:jsp="http://java.sun.com/JSP/Page">//declaring our tag in xhtml format if you want you can follow jsp format
<jsp:output omit-xml-declaration="true" />
<jsp:directive.page contentType="text/html" />
<head><title>Taxation, Taxation, Taxation</title></head>
<body>
<h1>Calculated Net Income</h1>
<p>My net income is:
<mytags:netincome grossIncome="${param.gross}"
allowance="${param.allowance}"
taxRate="${param.rate}"
currency="GBP" />//our custom tag
</p>
</body>
</html>
Step 4 :- Now create the myTags.tld wnder the webcontent by creating a folder name tags and place in it
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<tlib-version>1.0</tlib-version>
<short-name>MyTagLib</short-name>
<uri>http://www.osborne.com/mytags.tld</uri>
<tag>
<name>netincome</name>//our tagname implementation
<tag-class>web.prac.TaxationTag</tag-class>
<body-content>empty</body-content>
<attribute>
<name>grossIncome</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>allowance</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>taxRate</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>currency</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
Step 5 :- Now create the tag implementation class
package web.prac;
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
public class TaxationTag extends BodyTagSupport {
private String grossIncome;
private String taxRate;
private String allowance;
private String currency;
public void setAllowance(String allowance) {
this.allowance = allowance;
}
public void setGrossIncome(String grossIncome) {
this.grossIncome = grossIncome;
}
public void setTaxRate(String taxRate) {
this.taxRate = taxRate;
}
public void setCurrency(String currency) {
this.currency = currency;
}
public int doStartTag() throws JspException {
JspWriter out = pageContext.getOut();
double gross;
double rate;
double allow;
try {
/* Convert string input to numerics */
gross = Double.parseDouble(grossIncome);
rate = Double.parseDouble(taxRate);
allow = Double.parseDouble(allowance);
} catch (NumberFormatException nfe) {
try {
out.write("Bad Input Figures");
} catch (IOException ioe) {
ioe.printStackTrace();
}
return super.doStartTag();
}
double taxToPay = ((gross - allow) * rate / 100);
double net = (gross - taxToPay);
NumberFormat nf = NumberFormat.getInstance();
Currency c = Currency.getInstance(currency);
nf.setCurrency(c);
nf.setMinimumFractionDigits(c.getDefaultFractionDigits());
nf.setMaximumFractionDigits(c.getDefaultFractionDigits());
try {
out.print(c.getSymbol() + nf.format(net));
} catch (IOException e) {
e.printStackTrace();
}
return super.doStartTag();
}
}
Step 5 :- Now map it in web.xml
<?xml version="1.0" ?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<jsp-config>
<taglib>//declare our tag lib
<taglib-uri>http://www.x.y.z.com/taglibs/mytags</taglib-uri>
<taglib-location>/WEB-INF/tags/mytags.tld</taglib-location>
</taglib>
</jsp-config>
</web-app>
Step 6 :- Clean build and run the project
output :-Enter values an submit it
No comments:
Post a Comment