0 Replies Latest reply on May 15, 2003 8:41 AM by sabar

HTTP ERROR: 503 javax.servlet.ServletException: Query: can't

sabar May 15, 2003 8:41 AM

Hi

i am a newer with jboss and mysql and eclipse , i did the following steps to make my servlet connect to mysql :

1.create mysql data base [db.name]

2.copy mm.mysql-2.0.14-bin.jar to [jboss.dir]/server/default/lib

3. server/default/conf/standardjbosscmp-jdbc.xml, replace the Hyper SQL with these 2:
java:/MySqlDS
<datasource-mapping>mySQL</datasource-mapping>

4. server/default/conf/standardjaws.xml, replace the Hyper SQL with these 2:
java:/MySqlDS
<type-mapping>mySQL</type-mapping>

5. copy docs/examples/jca/mysql-service.xml into /server/default/deploy

6. update mysql-service.xml with your MySql login/password, and use the following:

<?xml version="1.0" encoding="UTF-8"?>















<depends optional-attribute-name="ManagedConnectionFactoryName">


MySqlDS

<config-property name="ConnectionURL" type="java.lang.String">jdbc:mysql://localhost:3306/partdb</config-property>
<config-property name="DriverClass" type="java.lang.String">org.gjt.mm.mysql.Driver</config-property>

<config-property name="userName" type="java.lang.String">test</config-property>
<config-property name="password" type="java.lang.String">test</config-property>



<depends optional-attribute-name="OldRarDeployment">jboss.jca:service=RARDeployment,name=JBoss LocalTransaction JDBC Wrapper

<depends optional-attribute-name="ManagedConnectionPool">


0
50
5000
15

ByContainer

<depends optional-attribute-name="CachedConnectionManager">jboss.jca:service=CachedConnectionManager

<depends optional-attribute-name="JaasSecurityManagerService">jboss.security:service=JaasSecurityManager

java:/TransactionManager

jboss.jca:service=RARDeployer

7. restart jboss

8. write my servlet within eclipse

package jdbctest;

import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.io.*;

/**
* @author Administrator
*
* To change this generated comment edit the template variable "typecomment":
* Window>Preferences>Java>Templates.
* To enable and disable the creation of type comments go to
* Window>Preferences>Java>Code Generation.
*/

public class Query extends HttpServlet {

Connection db; // This is the shared JDBC database connection

public void init() throws ServletException {
// Read initialization parameters from the web.xml file
ServletConfig config = getServletConfig();
String driverClassName = config.getInitParameter("DriverClass");
String url = config.getInitParameter("ConnectionURL");
String username = config.getInitParameter("username");
String password = config.getInitParameter("password");

// Use those init params to establish a connection to the database
// If anything goes wrong, log it, wrap the exception and re-throw it
try {
Class.forName(driverClassName);
db = DriverManager.getConnection(url, username, password);
}
catch (Exception e) {
log("Can't create DB connection", e);
throw new ServletException("Query: can't initialize: " +
e.getMessage(), e);
}
}

/** Close the database connection when the servlet is unloaded */
public void destroy() {
try { db.close(); } // Try to close the connection
catch (SQLException e) {} // Ignore errors; at least we tried!
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{

response.setContentType("text/html"); // We're outputting HTML
PrintWriter out = response.getWriter(); // Where to output it to

// Output document header and a form for entering SQL queries
// When the form is submitted, this servlet is reloaded
out.println("DB Query\n" +
"<body bgcolor=white><h1>DB Query</h1>\n" +
"Query: " +
"<input type=submit>");

// See if a query was specified in this request.
String query = request.getParameter("q");
if (query != null) {
// display the query text as a page heading
out.println("<h1>" + query + "</h1>");

// Now try to execute the query and display the results in a table
Statement statement = null; // An object to execute the query
try {
// Create a statement to use
statement = db.createStatement();
// Use it to execute the specified query, and get result set
ResultSet results = statement.executeQuery(query);
// Ask for extra information about the results
ResultSetMetaData metadata = results.getMetaData();
// How many columns are there in the results?
int numcols = metadata.getColumnCount();

// Begin a table, and output a header row of column names
out.println("<table border=2>");
for(int i = 0; i < numcols; i++)
out.print("" + metadata.getColumnLabel(i+1) + "");
out.println("");

// Now loop through the "rows" of the result set
while(results.next()) {
// For each row, display the the values for each column
out.print("");
for(int i = 0; i < numcols; i++)
out.print("" + results.getObject(i+1) + "");
out.println("");
}
out.println(""); // end the table

}
catch (SQLException e) {
// If anything goes wrong (usually a SQL error) display the
// error to the user so they can correct it.
out.println("SQL Error: " + e.getMessage());
}
finally { // Whatever happens, always close the Statement object
try { statement.close(); }
catch(Exception e) {}
}
}

// Finally, end the HTML output
out.println("");
}
}

9- write web.xml

<?xml version="1.0" ?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">


<web-app>

<servlet-name>Query</servlet-name>
<display-name>This is the display name of my J2EE component</display-name>
This is the description of my J2EE component
<servlet-class>jdbctest.Query</servlet-class>

<init-param>
<param-name>ConnectionURL</param-name>
<param-value>jdbc:mysql://localhost:3306/partdb</param-value>
</init-param>

<init-param>
<param-name>DriverClass</param-name>
<param-value>org.gjt.mm.mysql.Driver</param-value>
</init-param>

<init-param>
<param-name>userName</param-name>
<param-value>test</param-value>
</init-param>

<init-param>
<param-name>password</param-name>
<param-value>test</param-value>
</init-param>

<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<error-page>
<error-code>404</error-code>
error.jsp
</error-page>

</web-app>

10- deploy my servlet and run it by

http://localhost:8080/webjdbc/servlet/jdbctest.Query

and got the following error

HTTP ERROR: 503 javax.servlet.ServletException: Query: can't initialize: null

pls tell me what is the wrong?