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anto dot justus at gmail dot com
5 years ago
Java - php class

Third-party classes are used within a PHP application,
I'll create a simple Java class that calculates
sales tax based upon a price and taxation rate
input by the user.

You'll need to compile salesTax.java using
the Java compiler before you can use this class
within the PHP script

import java.util.*;
import java.text.*;

public class SalesTax {

public String SalesTax(double price, double salesTax)

    double tax = price * salesTax;

    NumberFormat numberFormatter;

    numberFormatter = NumberFormat.getCurrencyInstance();

    String priceOut = numberFormatter.format(price);

    String taxOut = numberFormatter.format(tax);

    numberFormatter = NumberFormat.getPercentInstance();

    String salesTaxOut =

    String str = "A sales Tax of " + salesTaxOut +

                 " on " + priceOut + " equals " + taxOut + ".";

    return str;



file named salesTax.java, you'll need to compile it.

a new, compiled file named salesTax.class
will be created.

This is the compiled code that will be called by
PHP to perform the calculation based on the data
input by the user via an HTML form.



// Format the HTML form.

$salesTaxForm = <<<SalesTaxForm

<form action="SalesTaxInterface.php" method="post">

   Price (ex. 42.56):<br>

   <input type="text" name="price" size="15" maxlength="15" value=""><br>

   Sales Tax rate (ex. 0.06):<br>

   <input type="text" name="tax" size="15" maxlength="15" value=""><br>

   <input type="submit" name="submit"



if (! isset(
$submit)) :


else :

// Instantiate the SalesTax class.
$salesTax = new Java("SalesTax");

// Don't forget to typecast in order to

   // conform with the Java method specifications.

$price = (double) $price;
$tax = (double) $tax;

$salesTax->SalesTax($price, $tax);




Chances are you will encounter various
minor problems when you first attempt to integrate
Java and PHP functionality, particularly if you are a
relative newcomer to the Java programming
environment. Even if the Java code compiles
correctly, you may still encounter problems,
largely due to differences found between the
two languages.

two of these differences here:

Data types

PHP is a loosely-typed language, which means it is
rather lenient on the way variables are used.
On the contrary, Java is a strongly-typed language,
which means that its policies for handling
variables and data types are rather stringent.
To illustrate the problem this difference poses,
take a moment to again review the code.
Notice that I had to typecast the $price and
$tax variables before passing them to the
SalesTax() method, because this
method requires that both input parameters
are of type "double." If this is not done, then
input such as 24 for price would cause an
error to occur.

Furthermore, if you are not adamant in
ensuring the correct data types are passed
to the Java methods, you may receive
unexpected results, although it will not be
outwardly apparent that an error has occurred.
Therefore, be careful!

Error reporting

Errors occurring within a PHP script are reported
in accordance with the level of error-reporting
specified in the php.ini file. Because the
Java code is called from within the PHP script,
any errors that arise from the Java code are
displayed as PHP errors. If you would like to
prevent these errors from being displayed
to the browser, simply prefix a @ symbol to
the PHP command.
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