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Tedious and error prone

Writing raw HTML code is not fun even under the best of circumstances. That is why I use a WYSIWYG HTML editor for authoring these modules.

Even for this very simple servlet, the process of constructing the output HTML code using Java println statements was very tedious and error prone. Much of the difficulty arises from the fact that Java strings must be enclosed inmatching double quotes and all HTML attribute values must also be enclosed in matching double or single quotes. As you can see from Listing 16 , the requirement to escape double quotes inside Java strings with the backslashcharacter can lead to some very confusing code. (I suppose it might be less confusing if I were to use single quotes instead of double quotes on HTML attributevalues. I will try that in the next module.)

In any event, the next section presents a JSP version of the same servlet. JSP intermingles HTML code with Java code and greatly reduces the amount of HTMLcode that must be constructed using Java println statements in a servlet. If you are unfamiliar with JSP, you can learn about it in the modules that begin at Java4305: Preface to JSP .

The JSP program

A complete listing of the JSP version of this program is provided in Listing 17 . I found this JSP version much easier to write than the servlet version discussed above. Admittedly, however, I wrote the servlet version first, so that probablyhelped to make it easier to write the JSP version.

I wrote all of the HTML code using Microsoft Expression Web 4, which provides both a WYSIWYG capability and a raw HTML editing capability. Once I confirmed that theHTML code was correct and valid, I went back and inserted the JSP tags containing the Java code.

As mentioned earlier, the JSP does not get and use the name of the computer on which it is running. Instead it uses the generic name localhost, which limitsthe ability to access the JSP from another computer on the network.

Interesting code fragments

Once again, I will discuss this program in fragments. A complete listing of the program is provided in Listing 17 .

Create basic web page structure

Listing 10 shows the HTML code that is roughly equivalent to the Java code in Listing 4 through Listing 7 . This code creates the HTML header and the basic structure of the web page shownin Figure 1 .

Listing 10 - Create basic web page structure.
<html><head><title>Java4550a</title></head><body><form method="get" action="http://localhost:8080/Java4550a.jsp"><p>Enter a name and press the button</p><p>Name:<input type="text" name="firstName"/></p><input type="submit" value="Submit Name"/><p>Your list of names is:<br/>

A JSP scriptlet

Listing 11 is a scriptlet containing pure Java code. It begins by getting the data from the request object. Then it deals withthe situation where nothing has been entered into the text field in Figure 1 , reporting that the list is empty. It ends with the beginning of a for loop that is executed when the array is not empty. Recall that in JSP, Java code blocks can begin in one scriptlet andend in another scriptlet later in the page. That is what is happening here.

Questions & Answers

show that the set of all natural number form semi group under the composition of addition
Nikhil Reply
explain and give four Example hyperbolic function
Lukman Reply
_3_2_1
felecia
⅗ ⅔½
felecia
_½+⅔-¾
felecia
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
x*x=2
felecia
2+2x=
felecia
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Shirley Reply
please can go further on polynomials quadratic
Abdullahi
hi mam
Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
yes i wantt to review
Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
please help me prove quadratic formula
Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
thank you help me with how to prove the quadratic equation
Seidu
may God blessed u for that. Please I want u to help me in sets.
Opoku
what is math number
Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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