How do I restrict access to servlets and JSPs?
The Java Servlet API Specification v2.2 allows you to
declaratively restrict access to specific Servlets and
JSPs using the Web Application Deployment descriptor.
Section 13.3.2 of the specification has an example
deployment descriptor that uses declarative security.
For more information, see Programming WebLogic HTTP
Servlets.
How do I protect WebLogic Server from security attacks
from bogus clients using the WL-Proxy-Client-Cert
header?
The WL-Proxy-Client-Cert header can be spoofed (used) by
any client which has direct access to WebLogic Server.
WebLogic Server takes the certificate information from
that header, trusting that is came from a secure source
(the plug-in) and use that information to authenticate
the user. In previous releases of WebLogic Server, the
default behavior was to always trust that header. Now
you need to explicitly define trust of the WL-Proxy-Client-Cert
header. A new parameter clientCertProxy allows WebLogic
Server to on the implicit trust of the certificate
header. If you need an additional level of security, use
a connection filter to limit all connections into
WebLogic Server (therefore allowing WebLogic Server to
only accept connections from the machine on which the
plug-in is running).
The clientCertProxy parameter has been added to the
HTTPClusterServlet and Web applications.
For the HTTPClusterServlet, add the parameter to the
web.xml file as follows:
<context-param>
<param-name>clientCertProxy</param-name>
<param-value>true</param-value>
</context-param>
For Web applications, add the parameter to the web.xml
file as follows:
ServletRequestImpl context-param
<context-param>
<param-name>weblogic.http.clientCertProxy</param-name>
<param-value>true</param-value>
</context-param>
You can also use this parameter in a cluster as follows:
<Cluster ClusterAddress="127.0.0.1" Name="MyCluster"
ClientCertProxyHeader="true"/>
Which XML parser comes with WebLogic Server 6.1?
We bundle a parser, based on Apache's Xerces 1.3.1
parser, in WebLogic Server 6.1. In addition, we include
a WebLogic proprietary high-performance non-validating
parser that you can use for small to medium sized XML
documents. The WebLogic XML Registry allows you to
configure the parser you want to use for specific
document types.
Can I use the getAttribute() and setAttribute() methods
of Version 2.2 of the Java Servlet API to parse XML
documents?
Yes. Use the setAttribute() method for SAX mode parsing
and the getAttribute() method for DOM mode parsing.
Using these methods in a Servlet, however, is a
WebLogic-specific feature. This means that the Servlet
may not be fully portable to other Servlet engines, so
use the feature with caution.
How can I avoid ResourceExceptions when sending more
requests for database connections from the pool than are
currently available?
The fundamental problem is too few resources (database
connections in the connection pool) for the work load.
The correct response is to increase the maximum number
of connections in the connection pool. Optimally
designed applications only require the server to have
one pool connection per execute thread.
The proper application response to a resource exception
is not to retry the request in a tight loop, which would
tie up execute threads on the server.
You should design your application to gracefully fail if
no connections are available. Try to ensure that you get
the connection as late as possible in your application
code and return them to the pool as early as possible so
that you do not see as many NoResource exceptions. It is
better to have the connection as a method level variable
and close the connection in a finally block as in the
following example:
try{
...
} catch(Exception handleEx) {
...
} finally {
try{ conn.close();
}catch (Exception ignore){} // always return the
connection to pool
}
How do I use Unicode codesets with the WebLogic jDriver
for Oracle driver?
To use Unicode codesets:
1. Install the appropriate codeset when you install
Oracle. If you did not do this in the original
installation, you will need to re-run the Oracle
installer and install the proper codeset.
2. Define the NLS_LANG variable in the environment where
the JDBC driver is running. Do this by assigning the
proper codeset to NLS_LANG in the shell from where you
start the WebLogic Server.
The Developers Guide has more information about
internationalization support.
How do I bind string values in a PreparedStatement?
Suppose you are trying to tget the PreparedStatement
class to bind Strings in a statement. The setString()
method doesn't seem to work. Here is how you have set up
the PreparedStatement:
String pstmt = "select n_name from n_table where n_name
LIKE
'?%'";
PreparedStatement ps = conn.prepareStatement(pstmt);
ps.setString(1, "SMIT");
ResultSet rs = ps.executeQuery();
The preceding code does not work because the complete
value needs to be specified in a String (without using
embedded quotes) and then bound to an unquoted
question-mark (?). Here is the corrected code:
String matchvalue = "smit%";
String pstmt = "select n_name from n_table where n_name
LIKE ?";
PreparedStatement ps = conn.prepareStatement(pstmt);
ps.setString(1, matchvalue);
ResultSet rs = ps.executeQuery();
How do I look up an "ORA" SQLException?
If your WebLogic jDriver for Oracle application produces
an SQLException such as:
java.sql.SQLException: ORA-12536: TNS: operation would
block
You can look up an Oracle error by using the oerr
command. For example, the description of error ORA-12536
can be found with the command:
> oerr ora 12536
What is error "ORA-6502?"
The default length of a string bound to an OUTPUT
parameter of a CallableStatement is 128 characters. If
the value you assign to the bound parameter exceeds that
length, you will get this error.
You can adjust the length of the value of the bound
parameter by passing an explicit length with the scale
argument to the
CallableStatement.registerOutputParameter() method.
How can I control on which WebLogic Server(s) my
application will run?
A system administrator can specify on which WebLogic
Server(s) applications will run by specifying targets
when configuring connection factories. Each connection
factory can be deployed on multiple WebLogic servers.
Note: If you use the default connection factory, you
have no control over the WebLogic server on which the
connection factory may be deployed. If you would like to
target a particular WebLogic server, create a new
connection factory and specify the appropriate JMS
server target(s).
How do I use a startup class to initialize and later
reference JMS objects?
You can use a shutdown class that does something like
the following: JMSobject WLSobject = null; try {
WLSobject = JMSStartUp.getJMSobject();
WLSobject.JMSCleanup(); } catch(Exception e) {} Servlets
can provide a nice solution to provide both
initialization and cleanup.
Page Numbers :
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
