Table of Contents
This section explains how to use MySQL Connector/J with GlassFish ™ Server Open Source Edition 3.0.1. GlassFish can be downloaded from the GlassFish website.
Once GlassFish is installed, make sure it can access MySQL Connector/J. To do
this, copy the MySQL Connector/J jar file to the
domain-dir/libmysql-connector-java-5.1.30-bin.jar to
C:\.
Restart the GlassFish Application Server. For more information,
see “Integrating the JDBC Driver” in
GlassFish Server Open Source Edition Administration
Guide, available at
GlassFish
Server Documentation.
glassfish-install-path\domains\domain-name\lib
You are now ready to create JDBC Connection Pools and JDBC Resources.
Creating a Connection Pool
In the GlassFish Administration Console, using the navigation tree navigate to Resources, JDBC, Connection Pools.
In the JDBC Connection Pools frame click . You will enter a two step wizard.
In the Name field under General
Settings enter the name for the connection pool,
for example enter MySQLConnPool.
In the Resource Type field, select
javax.sql.DataSource from the drop-down
listbox.
In the Database Vendor field, select
MySQL from the drop-down listbox. Click
to go to the next page of the
wizard.
You can accept the default settings for General Settings, Pool Settings and Transactions for this example. Scroll down to Additional Properties.
In Additional Properties you will need to ensure the following properties are set:
ServerName - The server
to connect to. For local testing this will be
localhost.
User - The user name with which to connect to MySQL.
Password - The corresponding password for the user.
DatabaseName - The
database to connect to, for example the sample MySQL
database World.
Click to exit the wizard. You will be taken to the JDBC Connection Pools page where all current connection pools, including the one you just created, will be displayed.
In the JDBC Connection Pools frame click on the connection pool you just created. Here, you can review and edit information about the connection pool. Because Connector/J does not support optimized validation queries, go to the Advanced tab, and under Connection Validation, configure the following settings:
Connection Validation - select Required.
Validation Method - select table from the drop-down menu.
Table Name - enter
DUAL.
To test your connection pool click the button at the top of the frame. A message will be displayed confirming correct operation or otherwise. If an error message is received recheck the previous steps, and ensure that MySQL Connector/J has been correctly copied into the previously specified location.
Now that you have created a connection pool you will also need to create a JDBC Resource (data source) for use by your application.
Creating a JDBC Resource
Your Java application will usually reference a data source object to establish a connection with the database. This needs to be created first using the following procedure.
Using the navigation tree in the GlassFish Administration Console, navigate to Resources, JDBC, JDBC Resources. A list of resources will be displayed in the JDBC Resources frame.
Click . The New JDBC Resource frame will be displayed.
In the JNDI Name field, enter the JNDI
name that will be used to access this resource, for example
enter jdbc/MySQLDataSource.
In the Pool Name field, select a connection pool you want this resource to use from the drop-down listbox.
Optionally, you can enter a description into the Description field.
Additional properties can be added if required.
Click to create the new JDBC resource. The JDBC Resources frame will list all available JDBC Resources.
This section shows how to deploy a simple JSP application on GlassFish, that connects to a MySQL database.
This example assumes you have already set up a suitable
Connection Pool and JDBC Resource, as explained in the preceding
sections. It is also assumed you have a sample database
installed, such as world.
The main application code, index.jsp is
presented here:
<%@ page import="java.sql.*, javax.sql.*, java.io.*, javax.naming.*" %>
<html>
<head><title>Hello world from JSP</title></head>
<body>
<%
InitialContext ctx;
DataSource ds;
Connection conn;
Statement stmt;
ResultSet rs;
try {
ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");
//ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource");
conn = ds.getConnection();
stmt = conn.createStatement();
rs = stmt.executeQuery("SELECT * FROM Country");
while(rs.next()) {
%>
<h3>Name: <%= rs.getString("Name") %></h3>
<h3>Population: <%= rs.getString("Population") %></h3>
<%
}
}
catch (SQLException se) {
%>
<%= se.getMessage() %>
<%
}
catch (NamingException ne) {
%>
<%= ne.getMessage() %>
<%
}
%>
</body>
</html>
In addition two XML files are required:
web.xml, and
sun-web.xml. There may be other files
present, such as classes and images. These files are organized
into the directory structure as follows:
index.jsp WEB-INF | - web.xml - sun-web.xml
The code for web.xml is:
<?xml version="1.0" encoding="UTF-8"?>
<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">
<display-name>HelloWebApp</display-name>
<distributable/>
<resource-ref>
<res-ref-name>jdbc/MySQLDataSource</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
</web-app>
The code for sun-web.xml is:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 8.1 Servlet 2.4//EN" "http://www.sun.com/software/appserver/dtds/sun-web-app_2_4-1.dtd">
<sun-web-app>
<context-root>HelloWebApp</context-root>
<resource-ref>
<res-ref-name>jdbc/MySQLDataSource</res-ref-name>
<jndi-name>jdbc/MySQLDataSource</jndi-name>
</resource-ref>
</sun-web-app>
These XML files illustrate a very important aspect of running
JDBC applications on GlassFish. On GlassFish it is important to
map the string specified for a JDBC resource to its JNDI name,
as set up in the GlassFish administration console. In this
example, the JNDI name for the JDBC resource, as specified in
the GlassFish Administration console when creating the JDBC
Resource, was jdbc/MySQLDataSource. This must
be mapped to the name given in the application. In this example
the name specified in the application,
jdbc/MySQLDataSource, and the JNDI name,
happen to be the same, but this does not necessarily have to be
the case. Note that the XML element <res-ref-name> is used
to specify the name as used in the application source code, and
this is mapped to the JNDI name specified using the
<jndi-name> element, in the file
sun-web.xml. The resource also has to be
created in the web.xml file, although the
mapping of the resource to a JNDI name takes place in the
sun-web.xml file.
If you do not have this mapping set up correctly in the XML files you will not be able to lookup the data source using a JNDI lookup string such as:
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");
You will still be able to access the data source directly using:
ds = (DataSource) ctx.lookup("jdbc/MySQLDataSource");
With the source files in place, in the correct directory structure, you are ready to deploy the application:
In the navigation tree, navigate to Applications - the Applications frame will be displayed. Click .
You can now deploy an application packaged into a single WAR file from a remote client, or you can choose a packaged file or directory that is locally accessible to the server. If you are simply testing an application locally you can simply point GlassFish at the directory that contains your application, without needing to package the application into a WAR file.
Now select the application type from the
Type drop-down listbox, which in this
example is Web application.
Click OK.
Now, when you navigate to the Applications
frame, you will have the option to Launch,
Redeploy, or Restart
your application. You can test your application by clicking
Launch. The application will connection to
the MySQL database and display the Name and Population of
countries in the Country table.
This section describes a simple servlet that can be used in the
GlassFish environment to access a MySQL database. As with the
previous section, this example assumes the sample database
world is installed.
The project is set up with the following directory structure:
index.html
WEB-INF
|
- web.xml
- sun-web.xml
- classes
|
- HelloWebServlet.java
- HelloWebServlet.class
The code for the servlet, located in
HelloWebServlet.java, is as follows:
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;
public class HelloWebServlet extends HttpServlet {
InitialContext ctx = null;
DataSource ds = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "SELECT Name, Population FROM Country WHERE Name=?";
public void init () throws ServletException {
try {
ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/MySQLDataSource");
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
}
catch (SQLException se) {
System.out.println("SQLException: "+se.getMessage());
}
catch (NamingException ne) {
System.out.println("NamingException: "+ne.getMessage());
}
}
public void destroy () {
try {
if (rs != null)
rs.close();
if (ps != null)
ps.close();
if (conn != null)
conn.close();
if (ctx != null)
ctx.close();
}
catch (SQLException se) {
System.out.println("SQLException: "+se.getMessage());
}
catch (NamingException ne) {
System.out.println("NamingException: "+ne.getMessage());
}
}
public void doPost(HttpServletRequest req, HttpServletResponse resp){
try {
String country_name = req.getParameter("country_name");
resp.setContentType("text/html");
PrintWriter writer = resp.getWriter();
writer.println("<html><body>");
writer.println("<p>Country: "+country_name+"</p>");
ps.setString(1, country_name);
rs = ps.executeQuery();
if (!rs.next()){
writer.println("<p>Country does not exist!</p>");
}
else {
rs.beforeFirst();
while(rs.next()) {
writer.println("<p>Name: "+rs.getString("Name")+"</p>");
writer.println("<p>Population: "+rs.getString("Population")+"</p>");
}
}
writer.println("</body></html>");
writer.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
public void doGet(HttpServletRequest req, HttpServletResponse resp){
try {
resp.setContentType("text/html");
PrintWriter writer = resp.getWriter();
writer.println("<html><body>");
writer.println("<p>Hello from servlet doGet()</p>");
writer.println("</body></html>");
writer.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
}
In the preceding code a basic doGet() method
is implemented, but is not used in the example. The code to
establish the connection with the database is as shown in the
previous example,
Section 13.1, “A Simple JSP Application with GlassFish, Connector/J and MySQL”,
and is most conveniently located in the servlet
init() method. The corresponding freeing of
resources is located in the destroy method. The main
functionality of the servlet is located in the
doPost() method. If the user enters into the
input form a country name that can be located in the database,
the population of the country is returned. The code is invoked
using a POST action associated with the input form. The form is
defined in the file index.html:
<html>
<head><title>HelloWebServlet</title></head>
<body>
<h1>HelloWebServlet</h1>
<p>Please enter country name:</p>
<form action="HelloWebServlet" method="POST">
<input type="text" name="country_name" length="50" />
<input type="submit" value="Submit" />
</form>
</body>
</html>
The XML files web.xml and
sun-web.xml are as for the example in the
preceding section,
Section 13.1, “A Simple JSP Application with GlassFish, Connector/J and MySQL”,
no additional changes are required.
When compiling the Java source code, you will need to specify
the path to the file javaee.jar. On
Windows, this can be done as follows:
shell> javac -classpath c:\glassfishv3\glassfish\lib\javaee.jar HelloWebServlet.java
Once the code is correctly located within its directory structure, and compiled, the application can be deployed in GlassFish. This is done in exactly the same way as described in the preceding section, Section 13.1, “A Simple JSP Application with GlassFish, Connector/J and MySQL”.
Once deployed the application can be launched from within the GlassFish Administration Console. Enter a country name such as “England”, and the application will return “Country does not exist!”. Enter “France”, and the application will return a population of 59225700.