It's My World: Januari 2012

Servlet adalah program java yang berjalan pada web server dengan pengaksesan model request-response. Di bawah ini akan dijelaskan bagaimana membuat program Kalkulator sederhana dengan menggunakan Servlet.

Cara Membuat Kalkulator Servlet

Berikut adalah cara membuat Kalkulator Servlet sederhana...

1) Buka Netbeans, pastikan Apache Tomcat telah terinstall, dan Xampp telah aktif (Apache)

2) Buat Project baru, dengan kategori Java Web, Web Application, klik Next.
Beri nama KalkulatorServlet (nama bebas), klik Next.
Biarkan framework, lalu klik Finish.

3) Buat servlet baru pada project, dengan klik kanan pada Project KalkulatorServlet, pilih New, lalu Servlet, beri nama Kalkulator, klik Next.
Tulis Servlet pada field package.
Pada URL Pattern, ubah "/Kalkulator" menjadi "/kalkulator" (optional), lalu klik Finish.

4) Di dalam servlet Kalkulator terdapat method "ProcessRequest". Di bagian tersebut terdapat try { }. Blok seluruh code komentar yang terdapat dalam blok try { }, ganti dengan code di bawah ini...

out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Kalkulator</title>");
out.println("</head>");
out.println("<body>");
out.println("<table border='0' width='800'>");

/** Judul Kalkulator **/
out.println("<tr align='center'><td><h1>Kalkulator Servlet</h1></td></tr>");
out.println("<tr align='center'><td><h4>Anissa Siti Rahma"
+ " -- 109091000073 -- SE5D</h4></td></tr>");
out.println("</table>");
out.println("");
out.println("<table border='0' width='800'>"+

/** Kalkulator Aritmatika **/
"<tr>"+
"<form method='post' action='hitung'><td width='350'>"+
"<fieldset>"+
"<center><h3>Kalkulator Aritmatika</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan 1 : "+"<input type='text' name='first' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Bilangan 2 : "+"<input type='text' name='second' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='+' name='tambah'/></td>"+
"<td align='center'><input type='submit' value='-' name='kurang'/></td>"+
"<td align='center'><input type='submit' value='x' name='kali'/></td>"+
"<td align='center'><input type='submit' value='/' name='bagi'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='%' name='mod'/></td>"+
"<td align='center'><input type='submit' value='^' name='pangkat'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil' value=''/>"+"</br></br>" +
"</td></tr>"+
"</table>"+
"</fieldset></td></form>"+

/** Kalkulator Scientific **/
"<td width='100'>    </td>"+
"<form method='post' action='hitung2'><td width='350' valign='top'>"+
"<fieldset>" +
"<center><h3>Kalkulator Scientific</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan : "+"<input type='text' name='third' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='sin' name='sin'/></td>"+
"<td align='center'><input type='submit' value='cos' name='cos'/></td>"+
"<td align='center'><input type='submit' value='tan' name='tan'/></td>"+
"<td align='center'><input type='submit' value='akar' name='akar'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='log' name='log'/></td>"+
"<td align='center'><input type='submit' value='exp' name='exp'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil2' value=''/>"+
"</td></tr>"+
"<tr><td colspan='4'> </td></tr>"+
"</table>"+
"</fieldset></td></form></tr></table>");
out.println("</body>");
out.println("</html>");

5) Buat New Servlet lagi pada package Servlet, beri nama Hitung, klik Next.
Ubah URL Pattern, dari /Hitung menjadi /hitung, lalu klik Finish.

6) Sama seperti pada servlet Kalkulator, pada servlet Hitung ini terdapat method "ProcessRequest". Sebelum blok try { }, tambahkan

String first = request.getParameter("first");
String second = request.getParameter("second");

Lalu Blok seluruh code komentar di dalam blok try { }, hapus lalu masukkan code di bawah ini...

double firstn = Double.parseDouble(first);
double secondn = Double.parseDouble(second);

double result = 0;

/**Melakukan Perhitungan**/
if(request.getParameter("tambah") != null) {
result = firstn + secondn;
}

else if(request.getParameter("kurang") != null) {
result = firstn - secondn;
}

else if(request.getParameter("kali") != null) {
result = firstn * secondn;
}

else if(request.getParameter("bagi")!= null) {
result = firstn / secondn;
}

else if(request.getParameter("mod") != null) {
result = firstn % secondn;
}

else if(request.getParameter("pangkat") != null) {
result = Math.pow(firstn, secondn);
}

out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Kalkulator</title>");
out.println("</head>");
out.println("<body>");
out.println("<table border='0' width='800'>");
out.println("<tr align='center'><td><h1>Kalkulator Servlet</h1></td></tr>");
out.println("<tr align='center'><td><h4>Anissa Siti Rahma"
+ " -- 109091000073 -- SE5D</h4></td></tr>");
out.println("</table>");
out.println("");
out.println("<table border='0' width='800'>"+
"<tr>"+
"<form method='post' action='hitung'><td width='350'>"+
"<fieldset>"+
"<center><h3>Kalkulator Aritmatika</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan 1 : "+"<input type='text' name='first' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Bilangan 2 : "+"<input type='text' name='second' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='+' name='tambah'/></td>"+
"<td align='center'><input type='submit' value='-' name='kurang'/></td>"+
"<td align='center'><input type='submit' value='x' name='kali'/></td>"+
"<td align='center'><input type='submit' value='/' name='bagi'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='%' name='mod'/></td>"+
"<td align='center'><input type='submit' value='^' name='pangkat'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil' value='"+result+"'/>"+"</br></br>" +
"</td></tr>"+
"</table>"+
"</fieldset></td></form>"+
"<td width='100'>    </td>"+
"<form method='post' action='hitung2'><td width='350' valign='top'>"+
"<fieldset>" +

"<center><h3>Kalkulator Scientific</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan : "+"<input type='text' name='third' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='sin' name='sin'/></td>"+
"<td align='center'><input type='submit' value='cos' name='cos'/></td>"+
"<td align='center'><input type='submit' value='tan' name='tan'/></td>"+
"<td align='center'><input type='submit' value='akar' name='akar'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='log' name='log'/></td>"+
"<td align='center'><input type='submit' value='exp' name='exp'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil2' value=''/>"+
"</td></tr>"+
"<tr><td colspan='4'> </td></tr>"+
"</table>"+
"</fieldset></td></form></tr></table>");
out.println("</body>");
out.println("</html>");

7) Buat satu lagi New Servlet pada package Servlet, beri nama Hitung2, klik Next.
Ubah URL Pattern, dari /Hitung2 menjadi /hitung2, lalu klik Finish.

8) Sama seperti pada servlet Hitung, tambahkan kode di bawah ini sebelum blok try { }

Blok code komentar di dalam blok try { }, hapus dan masukkan kode di bawah ini...
String third = request.getParameter("third");

double thirdn = Double.parseDouble(third);

double result2 = 0;

if(request.getParameter("sin") != null) {
result2 = Math.sin(thirdn);
}
else if(request.getParameter("cos") != null) {
result2 = Math.cos(thirdn);
}
else if(request.getParameter("tan") != null) {
result2 = Math.tan(thirdn);
}
else if(request.getParameter("akar") != null) {
result2 = Math.sqrt(thirdn);
}
else if(request.getParameter("log") != null) {
result2 = Math.log(thirdn);
}
else if(request.getParameter("exp") != null) {
result2 = Math.exp(thirdn);
}

out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Kalkulator</title>");
out.println("</head>");
out.println("<body>");
out.println("<table border='0' width='800'>");
out.println("<tr align='center'><td><h1>Kalkulator Servlet</h1></td></tr>");
out.println("<tr align='center'><td><h4>Anissa Siti Rahma"
+ " -- 109091000073 -- SE5D</h4></td></tr>");
out.println("</table>");
out.println("");
out.println("<table border='0' width='800'>"+
"<tr>"+
"<form method='post' action='hitung'><td width='350'>"+
"<fieldset>"+
"<center><h3>Kalkulator Aritmatika</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan 1 : "+"<input type='text' name='first' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Bilangan 2 : "+"<input type='text' name='second' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='+' name='tambah'/></td>"+
"<td align='center'><input type='submit' value='-' name='kurang'/></td>"+
"<td align='center'><input type='submit' value='x' name='kali'/></td>"+
"<td align='center'><input type='submit' value='/' name='bagi'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='%' name='mod'/></td>"+
"<td align='center'><input type='submit' value='^' name='pangkat'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil' value=''/>"+"</br></br>" +
"</td></tr>"+
"</table>"+
"</fieldset></td></form>"+
"<td width='100'>    </td>"+
"<form method='post' action='hitung2'><td width='350' valign='top'>"+
"<fieldset>" +

"<center><h3>Kalkulator Scientific</h3></center>"+
"<table border='0' align='center'>"+
"<tr><td colspan='4'>"+
"Bilangan : "+"<input type='text' name='third' value='0'/>"+
"</td></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td align='center'><input type='submit' value='sin' name='sin'/></td>"+
"<td align='center'><input type='submit' value='cos' name='cos'/></td>"+
"<td align='center'><input type='submit' value='tan' name='tan'/></td>"+
"<td align='center'><input type='submit' value='akar' name='akar'/></td>"+
"</tr></tr><tr><td colspan='4'> </td></tr>"+
"<tr>"+
"<td></td>"+
"<td align='center'><input type='submit' value='log' name='log'/></td>"+
"<td align='center'><input type='submit' value='exp' name='exp'/></td>"+
"<td></td>"+
"</tr><tr><td colspan='4'> </td></tr>"+
"<tr><td colspan='4'>"+
"Hasil : "+"<input type='text' name='hasil2' value='"+result2+"'/>"+
"</td></tr>"+
"<tr><td colspan='4'> </td></tr>"+
"</table>"+
"</fieldset></td></form></tr></table>");
out.println("</body>");
out.println("</html>");

9) Dalam Project KalkulatorServlet terdapat package dengan nama "WEB-INF", di dalam nya terdapat ",|web.xml". Double click pada web.xml ini, akan muncul seperti tampilan di bawah, lalu klik XML.

10) Pada bagian paling bawah dari code web.xml ini terdapat tag welcome-file.
Ubah isi tag ini (yaitu idex.jsp) dengan kalkulator

Dengan demikian kalkulator servlet sederhana, telah selesai dibuat.

Cara Menjalankan Kalkulator Servlet

Berikut adalah cara menjalankan kalkulator servlet yang telah dibuat..

1) Build Project KalkulatorServlet dengan cara : klik kanan pada project, lalu klik Build. Lalu project akan di build terlebih dahulu agar dapat dijalankan