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Administering Server Environments for Oracle WebLogic Server
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5 Configuring Web Server Functionality

The following sections describe how to configure a Java EE Web application hosted on WebLogic Server to function as a standard HTTP Web server hosting static content. Web applications also can host dynamic content such as JSPs and Servlets. See Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Overview of Configuring Web Server Components

In addition to hosting dynamic Java-based distributed applications, WebLogic Server functions as a Web server that handles high-volume Web sites, serving static files such as HTML files and image files, as well as servlets and JavaServer Pages (JSP). WebLogic Server supports the HTTP 1.1 standard.

Configuring the Server

You can specify the port that each WebLogic Server listens on for HTTP requests. Although you can specify any valid port number, if you specify port 80, you can omit the port number from the HTTP request used to access resources over HTTP. For example, if you define port 80 as the listen port, you can use the form http://hostname/myfile.html instead of http://hostname:portnumber/myfile.html.

On UNIX systems, binding a process to a port lower than 1025 must be done from the account of a privileged user, usually root. Consequently, if you want WebLogic Server to listen on port 80, you must start WebLogic Server as a privileged user; yet it is undesirable from a security standpoint to allow long-running processes like WebLogic Server to run with more privileges than necessary. WebLogic Server needs root privileges only until the port is bound.

WebLogic Server provides capabilities to switch its UNIX user ID (UID) and/or UNIX group ID (GID) after it binds to port 80. You can change the UID (or GID) either through the Administration Console (see Configuring the Listen Port) or by accessing UnixMachineMBean using WLST. Use UnixMachineMBbean.setPostBindUID() to set the UID and enable the switch by setting UnixMachineMBean.setPostBindUIDEnabled() to true. Similarly, the GID can be changed using methods UnixMachineMBean.setPostBindGID() and UnixMachineMBean.setPostBindGIDEnabled().

You can switch to the UNIX account "nobody," which is the least privileged user on most UNIX systems. If desired, you may create a UNIX user account expressly for running WebLogic Server. Make sure that files needed by WebLogic Server, such as log files and the WebLogic classes, are accessible by the non-privileged user. Once ownership of the WebLogic process has switched to the non-privileged user, WebLogic will have the same read, write, and execute permissions as the non-privileged user.

You define a separate listen port for non-SSL and secure (using SSL) requests. For additional information on configuring listen ports, see Understanding Network Channels.

Configuring the Listen Port

  1. Use the Administration Console to set the listen port to port 80. See "Configure Listen Ports".

  2. If the machine hosting WebLogic Server is running Windows, skip to step 8.

  3. Use the Administration Console to create a new Unix Machine. See "Configure Machines".

  4. Select the Enable Post-Bind UID field.

  5. Enter the user name you want WebLogic Server to run as in the Post-Bind UID field.

  6. Select the Enable Post-Bind GID fields.

  7. Enter the group name you want WebLogic Server to run as in the Post-Bind GID field.

  8. Click Save.

  9. To activate these changes, in the Change Center of the Administration Console, click Activate Changes.

Web Applications

HTTP and Web applications are deployed according to the Java EE 6 Servlet 3.0 and JSP 2.2 specifications, which describe Web Applications as a standard for grouping the components of a Web-based application. These components include JSP pages, HTTP servlets, and static resources such as HTML pages or image files. In addition, a Web application can access external resources such as EJBs and JSP tag libraries. Each server can host any number of Web applications. You typically use the name of the Web application as part of the URI you use to request resources from the Web application.

For more information, see Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Web Applications and Clustering

Web applications can be deployed to a WebLogic Server cluster. When a user requests a resource from a Web application, the request is routed to one of the servers in the cluster that host the Web application. If an application uses a session object, then sessions must be replicated across the nodes of the cluster. Several methods of replicating sessions are provided.

For more information, see Administering Clusters for Oracle WebLogic Server.

Configuring Virtual Hosting

Virtual hosting allows you to define host names that servers or clusters respond to. When you use virtual hosting you use DNS to specify one or more host names that map to the IP address of a WebLogic Server instance or cluster, and you specify which Web applications are served by the virtual host. When used in a cluster, load balancing allows the most efficient use of your hardware, even if one of the DNS host names processes more requests than the others.

For example, you can specify that a Web application called books responds to requests for the virtual host name www.books.com, and that these requests are targeted to WebLogic Servers A,B, and C, while a Web application called cars responds to the virtual host name www.autos.com and these requests are targeted to WebLogic Servers D and E. You can configure a variety of combinations of virtual host, WebLogic Server instances, clusters, and Web applications, depending on your application and Web server requirements.

For each virtual host that you define you can also separately define HTTP parameters and HTTP access logs. The HTTP parameters and access logs set for a virtual host override those set for a server. You may specify any number of virtual hosts.

You activate virtual hosting by targeting the virtual host to a server or cluster of servers. Virtual hosting targeted to a cluster will be applied to all servers in the cluster.

Virtual Hosting and the Default Web Application

You can also designate a default Web Application for each virtual host. The default Web application for a virtual host responds to all requests that cannot be resolved to other Web applications deployed on the same server or cluster as the virtual host.

Unlike other Web applications, a default Web application does not use the Web application name (also called the context path) as part of the URI used to access resources in the default Web application.

For example, if you defined virtual host name www.mystore.com and targeted it to a server on which you deployed a Web application called shopping, you would access a JSP called cart.jsp from the shopping Web application with the following URI:

http://www.mystore.com/shopping/cart.jsp

If, however, you declared shopping as the default Web application for the virtual host www.mystore.com, you would access cart.jsp with the following URI:

http://www.mystore.com/cart.jsp

For more information, see How WebLogic Server Resolves HTTP Requests.

When using multiple Virtual Hosts with different default Web applications, you can not use single sign-on, as each Web application will overwrite the JSESSIONID cookies set by the previous Web application. This will occur even if the CookieName, CookiePath, and CookieDomain are identical in each of the default Web applications.

Setting Up a Virtual Host

  1. Use the Administration Console to define a virtual host. See "Virtual Host".

  2. Add a line naming the virtual host to the etc/hosts file on your server to ensure that the virtual host name can be resolved.

How WebLogic Server Resolves HTTP Requests

When WebLogic Server receives an HTTP request, it resolves the request by parsing the various parts of the URL and using that information to determine which Web application and/or server should handle the request. Table 5-1 demonstrates various combinations of requests for Web applications, virtual hosts, servlets, JSPs, and static files and the resulting response.

Note:

If you package your Web application as part of an Enterprise application, you can provide an alternate name for a Web application that is used to resolve requests to the Web application. For more information, see Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

Table 5-1 provides some sample URLs and the file that is served by WebLogic Server. The Index Directories Checked column refers to the Index Directories attribute that controls whether or not a directory listing is served if no file is specifically requested.

Table 5-1 Examples of How WebLogic Server Resolves URLs

URL Index Directories Checked? This file is served in response
http://host:port/apples

No

Welcome file* defined in the apples Web application.

http://host:port/apples

Yes

Directory listing of the top-level directory of the apples Web application.

http://host:port/oranges/naval

Does not matter

Servlet mapped with <url-pattern> of /naval in the oranges Web application.

There are additional considerations for servlet mappings. For more information, see "Configuring Servlets" in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

http://host:port/naval

Does not matter

Servlet mapped with <url-pattern> of /naval in the oranges Web application and oranges is defined as the default Web application.

For more information, see "Configuring Servlets" in Developing Web Applications, Servlets, and JSPs for Oracle WebLogic Server.

http://host:port/apples/pie.jsp

Does not matter

pie.jsp, from the top-level directory of the apples Web application.

http://host:port

Yes

Directory listing of the top-level directory of the default Web application

http://host:port

No

Welcome file* from the default Web application.

http://host:port/apples/myfile.html

Does not matter

myfile.html, from the top-level directory of the apples Web application.

http://host:port/myfile.html

Does not matter

myfile.html, from the top-level directory of the default Web application.

http://host:port/apples/images/red.gif

Does not matter

red.gif, from the images subdirectory of the top-level directory of the apples Web application.

http://host:port/myFile.html

Where myfile.html does not exist in the apples Web application and a default servlet has not been defined.

Does not matter

Error 404

http://www.fruit.com/

No

Welcome file from the default Web application for a virtual host with a host name of www.fruit.com.

http://www.fruit.com/

Yes

Directory listing of the top-level directory of the default Web application for a virtual host with a host name of www.fruit.com.

http://www.fruit.com/oranges/myfile.html

Does not matter

myfile.html, from the oranges Web application that is targeted to a virtual host with host name www.fruit.com.


Setting Up HTTP Access Logs

WebLogic Server can keep a log of all HTTP transactions in a text file, in either common log format or extended log format. Common log format is the default. Extended log format allows you to customize the information that is recorded. You can set the attributes that define the behavior of HTTP access logs for each server instance or for each virtual host that you define.

To set up HTTP logging for a server or a virtual host, refer to the following topics in the Oracle WebLogic Server Administration Console Online Help:

Log Rotation

You can rotate the log file based on either the size of the file or after a specified amount of time has passed. When either criterion is met, the current access log file is closed and a new access log file is started. If you do not configure log rotation, the HTTP access log file grows indefinitely. You can configure the name of the access log file to include a time and date stamp that indicates when the file was rotated. If you do not configure a time stamp, each rotated file name includes a numeric portion that is incremented upon each rotation. Separate HTTP access logs are kept for each Virtual Host you have defined.

Common Log Format

The default format for logged HTTP information is the common log format (see http://www.w3.org/Daemon/User/Config/Logging.html#common-logfile-format). This standard format follows the pattern:

host RFC931 auth_user [day/month/year:hour:minute:second
  UTC_offset] "request" status bytes

where:

host

Either the DNS name or the IP number of the remote client

RFC931

Any information returned by IDENTD for the remote client; WebLogic Server does not support user identification

auth_user

If the remote client user sent a userid for authentication, the user name; otherwise "-"

day/month/year:hour:minute:second UTC_offset

Day, calendar month, year and time of day (24-hour format) with the hours difference between local time and GMT, enclosed in square brackets

"request"

First line of the HTTP request submitted by the remote client enclosed in double quotes

status

HTTP status code returned by the server, if available; otherwise "-"

bytes

Number of bytes listed as the content-length in the HTTP header, not including the HTTP header, if known; otherwise "-"

Setting Up HTTP Access Logs by Using Extended Log Format

WebLogic Server also supports extended log file format, version 1.0, an emerging standard defined by the draft specification from the W3C at http://www.w3.org/TR/WD-logfile.html. The current definitive reference is on the W3C Technical Reports and Publications page at http://www.w3.org/TR/.

The extended log format allows you to specify the type and order of information recorded about each HTTP communication. To enable this format in the Administration Console:

  1. Navigate to the server-name > Logging > HTTP page.

  2. Make sure that HTTP access log file enabled is checked.

  3. Click Advanced.

  4. In the field labeled Format, select Extended.

In the field labeled Extended Logging Format Fields, you can select one or more of the fields described in Supported Field Identifiers. If you want to add custom fields to an HTTP access log file, see Creating Custom Field Identifiers for details.

You specify the information that should be recorded in the log file with directives, included in the actual log file itself. A directive begins on a new line and starts with a pound sign (#). If the log file does not exist, a new log file is created with default directives. However, if the log file already exists when the server starts, it must contain valid directives at the head of the file.

Creating the Fields Directive

The first line of your log file must contain a directive stating the version number of the log file format. You must also include a Fields directive near the beginning of the file:

#Version: 1.0
#Fields: xxxx xxxx xxxx ...

Where each xxxx describes the data fields to be recorded. Field types are specified as either simple identifiers, or may take a prefix-identifier format, as defined in the W3C specification. For example:

#Fields: date time cs-method cs-uri

This identifier instructs the server to record the date and time of the transaction, the request method that the client used, and the URI of the request for each HTTP access. Each field is separated by white space, and each record is written to a new line, appended to the log file.

Note:

The #Fields directive must be followed by a new line in the log file, so that the first log message is not appended to the same line.

Supported Field Identifiers

The following identifiers are supported, and do not require a prefix.

date

Date at which transaction completed, field has type <date>, as defined in the W3C specification.

time

Time at which transaction completed, field has type <time>, as defined in the W3C specification.

time-taken

Time taken for transaction to complete in seconds, field has type <fixed>, as defined in the W3C specification.

bytes

Number of bytes transferred, field has type <integer>.

Note that the cached field defined in the W3C specification is not supported in WebLogic Server.

The following identifiers require prefixes, and cannot be used alone. The supported prefix combinations are explained individually.

IP Address Related Fields

These fields give the IP address and port of either the requesting client, or the responding server. These fields have type <address>, as defined in the W3C specification. The supported fields are:

c-ip

The IP address of the client.

s-ip

The IP address of the server.

DNS Related Fields

These fields give the domain names of the client or the server and have type <name>, as defined in the W3C specification. The supported fields are:

c-dns

The domain name of the requesting client.

s-dns

The domain name of the requested server.

sc-status

Status code of the response, for example (404) indicating a ""File not found" status. This field has type <integer>, as defined in the W3C specification.

sc-comment

The comment returned with status code, for instance "File not found". This field has type <text>.

cs-method

The request method, for example GET or POST. This field has type <name>, as defined in the W3C specification.

cs-uri

The full requested URI. This field has type <uri>, as defined in the W3C specification.

cs-uri-stem

Only the stem portion of URI (omitting query). This field has type <uri>, as defined in the W3C specification.

cs-uri-query

Only the query portion of the URI. This field has type <uri>, as defined in the W3C specification.

Diagnostic Message Correlation Fields

These fields give message correlation information for diagnostic messages, helping you to determine relationships between messages across components. These fields are logged if the diagnostic context is present and populated for the executed request. The diagnostic context may be present if it is propagated into the server with the incoming request, or it may be created for the request by WebLogic Server if the diagnostic context is enabled. The supported fields are:

ctx-ecid

The Execution Context ID (ECID). The ECID is a globally unique identifier associated with the execution of a particular request.

ctx-rid

The Relationship ID (RID). The RID distinguishes the work done in one thread on one process, from work done by any other threads on this and other processes on behalf of the same request.

If the diagnostic context does not exist, or the values of the ECID and RID are not available in the diagnostic context, a hyphen (-) is logged as their values. For more information about the ECID and RID, see "Correlating Messages Across Log Files and Components" in Administering Oracle Fusion Middleware.

Creating Custom Field Identifiers

You can also create user-defined fields for inclusion in an HTTP access log file that uses the extended log format (ELF). To create a custom field, you identify the field in the ELF log file using the Fields directive and then you create a matching Java class that generates the desired output. You can create a separate Java class for each field, or the Java class can output multiple fields. For a sample of the Java source for such a class, see Java Class for Creating a Custom ELF Field.

To create a custom field:

  1. Include the field name in the Fields directive, using the form:

    x-myCustomField.
    

    Where myCustomField is a fully-qualified class name.

    For more information about the Fields directive, see Creating the Fields Directive.

  2. Create a Java class with the same fully-qualified class name as the custom field you defined with the Fields directive (for example myCustomField). This class defines the information you want logged in your custom field. The Java class must implement the following interface:

    weblogic.servlet.logging.CustomELFLogger
    

    In your Java class, you must implement the logField() method, which takes a HttpAccountingInfo object and FormatStringBuffer object as its arguments:

    • Use the HttpAccountingInfo object to access HTTP request and response data that you can output in your custom field. Getter methods are provided to access this information. For a complete listing of these get methods, see Get Methods of the HttpAccountingInfo Object.

    • Use the FormatStringBuffer class to create the contents of your custom field. Methods are provided to create suitable output.

  3. Compile the Java class and add the class to the CLASSPATH statement used to start WebLogic Server. You will probably need to modify the CLASSPATH statements in the scripts that you use to start WebLogic Server.

    Note:

    Do not place this class inside of a Web application or Enterprise application in exploded or jar format.

  4. Configure WebLogic Server to use the extended log format. For more information, see Setting Up HTTP Access Logs by Using Extended Log Format.

    Notes:

    When writing the Java class that defines your custom field, do not execute any code that is likely to slow down the system (For instance, accessing a DBMS or executing significant I/O or networking calls.) Remember, an HTTP access log file entry is created for every HTTP request.

    Note:

    If you want to output more than one field, delimit the fields with a tab character. For more information on delimiting fields and other ELF formatting issues, see "Extended Log Format" at http://www.w3.org/TR/WD-logfile-960221.html.

Get Methods of the HttpAccountingInfo Object

The following methods return various data regarding the HTTP request. These methods are similar to various methods of javax.servlet.ServletRequest, javax.servlet.http.Http.ServletRequest, and javax.servlet.http.HttpServletResponse.

The Javadoc for these interfaces is available at the following locations:

For details about these methods, see the corresponding methods in the Java interfaces listed in the following table, or refer to the specific information contained in this table.

Table 5-2 Getter Methods of HttpAccountingInfo

HttpAccountingInfo Methods Method Information
Object getAttribute(String name); 
javax.servlet.ServletRequest
Enumeration getAttributeNames(); 
javax.servlet.ServletRequest
String getCharacterEncoding(); 
javax.servlet.ServletRequest
int getResponseContentLength();
javax.servlet.ServletResponse.setContentLength()

This method gets the content length of the response, as set with the setContentLength() method.

String getContentType(); 
javax.servlet.ServletRequest
Locale getLocale();
javax.servlet.ServletRequest
Enumeration getLocales();
javax.servlet.ServletRequest
String getParameter(String name);
javax.servlet.ServletRequest
Enumeration getParameterNames();
javax.servlet.ServletRequest
String[] getParameterValues(String name);
javax.servlet.ServletRequest
String getProtocol();
javax.servlet.ServletRequest
String getRemoteAddr();
javax.servlet.ServletRequest
String getRemoteHost();
javax.servlet.ServletRequest
String getScheme();
javax.servlet.ServletRequest
String getServerName();
javax.servlet.ServletRequest
int getServerPort();
javax.servlet.ServletRequest
boolean isSecure();
javax.servlet.ServletRequest
String getAuthType();
javax.servlet.http.HttpServletRequest
String getContextPath();
javax.servlet.http.HttpServletRequest
Cookie[] getCookies();
javax.servlet.http.HttpServletRequest
long getDateHeader(String name);
javax.servlet.http.HttpServletRequest
String getHeader(String name);
javax.servlet.http.HttpServletRequest
Enumeration getHeaderNames();
javax.servlet.http.HttpServletRequest
Enumeration getHeaders(String name);
javax.servlet.http.HttpServletRequest
int getIntHeader(String name);
javax.servlet.http.HttpServletRequest
String getMethod();
javax.servlet.http.HttpServletRequest
String getPathInfo();
javax.servlet.http.HttpServletRequest
String getPathTranslated();
javax.servlet.http.HttpServletRequest
String getQueryString();
javax.servlet.http.HttpServletRequest
String getRemoteUser();
javax.servlet.http.HttpServletRequest
String getRequestURI();
javax.servlet.http.HttpServletRequest
String getRequestedSessionId();
javax.servlet.http.HttpServletRequest
String getServletPath();
javax.servlet.http.HttpServletRequest
Principal getUserPrincipal();
javax.servlet.http.HttpServletRequest
boolean isRequestedSessionIdFromCookie();
javax.servlet.http.HttpServletRequest
boolean isRequestedSessionIdFromURL();
javax.servlet.http.HttpServletRequest
boolean isRequestedSessionIdFromUrl();
javax.servlet.http.HttpServletRequest
boolean isRequestedSessionIdValid();
javax.servlet.http.HttpServletRequest
byte[] getURIAsBytes();

Returns the URI of the HTTP request as byte array, for example: If GET /index.html HTTP/1.0 is the first line of an HTTP Request, /index.html is returned as an array of bytes.

long getInvokeTime();

Returns the starting time of currentTimeMillis().

To get the length of time taken by the servlet to send the response to the client, use the following code:

long milsec = System.currentTimeMillis() - metrics.getInvokeTime();

Float sec = new Float(milsec / 1000.0);

int getResponseStatusCode();
javax.servlet.http.HttpServletResponse
String getResponseHeader(String name);
javax.servlet.http.HttpServletResponse

Example 5-1 Java Class for Creating a Custom ELF Field

import weblogic.servlet.logging.CustomELFLogger;
import weblogic.servlet.logging.FormatStringBuffer;
import weblogic.servlet.logging.HttpAccountingInfo;
/* This example outputs the User-Agent field into a
 custom field called MyCustomField
*/
public class MyCustomField implements CustomELFLogger{
public void logField(HttpAccountingInfo metrics,
  FormatStringBuffer buff) {
  buff.appendValueOrDash(metrics.getHeader("User-Agent"));
  }
}

Preventing POST Denial-of-Service Attacks

A Denial-of-Service attack is a malicious attempt to overload a server with phony requests. One common type of attack is to send huge amounts of data in an HTTP POST method. You can set three attributes in WebLogic Server that help prevent this type of attack. These attributes are set in the Console, under Servers or Virtual Hosts. If you define these attributes for a virtual host, the values set for the virtual host override those set under Servers.

PostTimeoutSecs

Amount of time that WebLogic Server waits between receiving chunks of data in an HTTP POST.

The default value for PostTimeoutSecs is 30.

MaxPostTimeSecs

Maximum time that WebLogic Server spends receiving post data. If this limit is triggered, a PostTimeoutException is thrown and the following message is sent to the server log:

Post time exceeded MaxPostTimeSecs.

The default value for MaxPostTimeSecs is 30.

MaxPostSize

Maximum number of bytes of data received in a POST from a single request. If this limit is triggered, a MaxPostSizeExceeded exception is thrown and the following message is sent to the server log:

POST size exceeded the parameter MaxPostSize.

An HTTP error code 413 (Request Entity Too Large) is sent back to the client.

If the client is in listening mode, it gets these messages. If the client is not in listening mode, the connection is broken.

The default value for MaxPostSize is -1.

Setting Up WebLogic Server for HTTP Tunneling

HTTP tunneling provides a way to simulate a stateful socket connection between WebLogic Server and a Java client when your only option is to use the HTTP protocol. It is generally used to tunnel through an HTTP port in a security firewall. HTTP is a stateless protocol, but WebLogic Server provides tunneling functionality to make the connection appear to be a regular T3Connection. However, you can expect some performance loss in comparison to a normal socket connection.

Configuring the HTTP Tunneling Connection

Under the HTTP protocol, a client may only make a request, and then accept a reply from a server. The server may not voluntarily communicate with the client, and the protocol is stateless, meaning that a continuous two-way connection is not possible.

WebLogic HTTP tunneling simulates a T3Connection via the HTTP protocol, overcoming these limitations. There are attributes that you can configure in the Administration Console to tune a tunneled connection for performance. It is advised that you leave them at their default settings unless you experience connection problems. These properties are used by the server to determine whether the client connection is still valid, or whether the client is still alive.

Enable Tunneling

Enables or disables HTTP tunneling. HTTP tunneling is disabled by default.

Note that the server must also support both the HTTP and T3 protocols in order to use HTTP tunneling.

Tunneling Client Ping

When an HTTP tunnel connection is set up, the client automatically sends a request to the server, so that the server may volunteer a response to the client. The client may also include instructions in a request, but this behavior happens regardless of whether the client application needs to communicate with the server. If the server does not respond (as part of the application code) to the client request within the number of seconds set in this attribute, it does so anyway. The client accepts the response and automatically sends another request immediately.

Default is 45 seconds; valid range is 20 to 900 seconds.

Tunneling Client Timeout

If the number of seconds set in this attribute have elapsed since the client last sent a request to the server (in response to a reply), then the server regards the client as dead, and terminates the HTTP tunnel connection. The server checks the elapsed time at the interval specified by this attribute, when it would otherwise respond to the client's request.

Default is 40 seconds; valid range is 10 to 900 seconds.

Connecting to WebLogic Server from the Client

When your client requests a connection with WebLogic Server, all you need to do in order to use HTTP tunneling is specify the HTTP protocol in the URL. For example:

Hashtable env = new Hashtable();
env.put(Context.PROVIDER_URL, "http://wlhost:80");
Context ctx = new InitialContext(env);

On the client side, a special tag is appended to the http protocol, so that WebLogic Server knows this is a tunneling connection, instead of a regular HTTP request. Your application code does not need to do any extra work to make this happen.

The client must specify the port in the URL, even if the port is 80. You can set up your WebLogic Server instance to listen for HTTP requests on any port, although the most common choice is port 80 since requests to port 80 are customarily allowed through a firewall.

You specify the listen port for WebLogic Server in the Administration Console under the "Servers" node, under the "Network" tab.

Using Native I/O for Serving Static Files (Windows Only)

When running WebLogic Server on Windows NT/2000/XP you can specify that WebLogic Server use the native operating system call TransmitFile instead of using Java methods to serve static files such as HTML files, text files, and image files. Using native I/O can provide performance improvements when serving larger static files.

To use native I/O, add two parameters to the web.xml deployment descriptor of a Web application containing the files to be served using native I/O. The first parameter, weblogic.http.nativeIOEnabled should be set to TRUE to enable native I/O file serving. The second parameter, weblogic.http.minimumNativeFileSize sets the minimum file size for using native I/O. If the file being served is larger than this value, native I/O is used. If you do not specify this parameter, a value of 4K is used.

Generally, native I/O provides greater performance gains when serving larger files; however, as the load on the machine running WebLogic Server increases, these gains diminish. You may need to experiment to find the correct value for weblogic.http.minimumNativeFileSize.

The following example shows the complete entries that should be added to the web.xml deployment descriptor. These entries must be placed in the web.xml file after the <distributable> element and before <servlet> element.

<context-param>
  <param-name>weblogic.http.nativeIOEnabled</param-name>
  <param-value>TRUE</param-value>
</context-param>
<context-param>
  <param-name>weblogic.http.minimumNativeFileSize</param-name>
  <param-value>500</param-value>
</context-param>

weblogic.http.nativeIOEnabled can also be set as a context parameter in the FileServlet.