import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.io.*;
import java.sql.*;
/*
PhoneBook.java:
Example of a middle-tier Java application - a servlet
accessing a back-end database.
Copyright (c) 1999 Nathan Meyers
$Id: PhoneBook.java,v 1.6 1999/11/10 03:44:25 nathanm Exp $
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject
to the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
public class PhoneBook extends HttpServlet
{
Connection connection = null;
public void init(ServletConfig config) throws ServletException
{
// Servlet initialization
super.init(config);
try
{
// Load the MySQL JDBC driver
Class.forName("org.gjt.mm.mysql.Driver");
}
catch (ClassNotFoundException e)
{ throw new ServletException(e.toString()); }
}
private void doOutput1(PrintWriter writer)
{
writer.println(
"\n" +
"\n" +
"Phone Book" +
"\n" +
"\n" +
"
\n" +
"
Telephone Book
\n" +
" "
);
}
private void doOutput2(PrintWriter writer)
{
writer.println("");
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
{
// Get action puts up the query form.
resp.setContentType("text/html");
PrintWriter writer = null;
try {
writer = resp.getWriter();
}
catch (IOException e) { return; }
doOutput1(writer);
doOutput2(writer);
writer.close();
}
public synchronized void doPost(HttpServletRequest req,
HttpServletResponse resp)
{
// Post action puts up the query form and responds to the post
resp.setContentType("text/html");
PrintWriter writer = null;
try {
writer = resp.getWriter();
}
catch (IOException e) { return; }
// Output the form
doOutput1(writer);
// Open or reopen the connection if needed
try
{
// Open a connection to the server - no login or password.
// The form of the URL (first parameter) is dictated by the
// MySQL jdbc driver. Default MySQL TCP port is 3306
if (connection == null || connection.isClosed())
connection = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/test", "", "");
}
catch (SQLException e)
{
writer.println("Error: Cannot open database connection\n");
doOutput2(writer);
writer.close();
return;
}
// Open input from the POST data
ServletInputStream instream = null;
Hashtable postData = null;
try
{
// Build a hashtable of the posted data
postData = HttpUtils.parsePostData(
req.getContentLength(), req.getInputStream());
}
catch (IOException e)
{
writer.println("Error: Cannot read post data\n");
}
if (postData.containsKey("Add"))
{
// User requested to add a new entry... make sure
// at least last name is non-empty
if (((String[])postData.get("LastName"))[0].length() == 0)
writer.println("Error: No last name specified for Add");
else try
{
// Construct and execute an SQL statement to insert
Statement stmt = connection.createStatement();
stmt.executeUpdate(
"INSERT INTO phonelist VALUES (" +
"'" +
((String[])postData.get("LastName"))[0] +
"','" +
((String[])postData.get("FirstName"))[0] +
"','" +
((String[])postData.get("CountryCode"))[0] +
"','" +
((String[])postData.get("AreaCode"))[0] +
"','" +
((String[])postData.get("PhoneNum"))[0] +
"');");
writer.println("New entry added for " +
((String[])postData.get("LastName"))[0]);
}
catch (SQLException e)
{
writer.println("Error: " + e.toString());
}
catch (NullPointerException e)
{
// This will trigger if a form field is missing from
// the post.
writer.println("Error: " + e.toString());
}
}
else
{
// User requested a query...
ResultSet results = null;
try
{
// Construct an SQL query string. First figure out
// the qualifiers based on form input
StringBuffer queryQualifiers = new StringBuffer();
appendQueryQualifiers(queryQualifiers, "lastname",
(postData.get("LastName")));
appendQueryQualifiers(queryQualifiers, "firstname",
(postData.get("FirstName")));
appendQueryQualifiers(queryQualifiers, "countrycode",
(postData.get("CountryCode")));
appendQueryQualifiers(queryQualifiers, "areacode",
(postData.get("AreaCode")));
appendQueryQualifiers(queryQualifiers, "number",
(postData.get("PhoneNum")));
Statement stmt = connection.createStatement();
results = stmt.executeQuery(
"SELECT * FROM phonelist" +
queryQualifiers +
";"
);
if (results == null)
writer.println("Null result from query");
else
{
// Print headers
writer.println(
"
\n" +
"
\n" +
"
Last Name
\n" +
"
First Name
\n" +
"
Country Code
\n" +
"
Area Code
\n" +
"
Phone Number
\n" +
"
");
while (results.next())
{
writer.println(
"
" +
"
" + results.getString(1) + "
\n" +
"
" + results.getString(2) + "
\n" +
"
" + results.getString(3) + "
\n" +
"
" + results.getString(4) + "
\n" +
"
" + results.getString(5) + "
\n" +
"
");
}
writer.println("
");
}
}
catch (SQLException e)
{
writer.println("Error: " + e.toString());
}
}
doOutput2(writer);
writer.close();
}
// appendQueryQualifiers: A utility to assist in constructing
// the query string
private void appendQueryQualifiers(StringBuffer qualifiers,
String dbfield,
Object formdata)
{
if (formdata == null) return;
String forminfo = ((String[])formdata)[0];
// Was anything specified for this form field?
if (forminfo.length() > 0)
{
// Yes
if (qualifiers.length() == 0)
qualifiers.append(" WHERE");
else
qualifiers.append(" AND");
qualifiers.append(" " + dbfield + " = \"" +
forminfo + "\"");
}
}
public String getServletInfo()
{
return "PhoneBook";
}
}