| Sun ONE Application Server 7, Enterprise Edition Developer's Guide to Web Applications |
Chapter 6
Assembling and Deploying Web ModulesThis chapter describes how web modules are assembled and deployed in Sun ONE Application Server. For general assembly and deployment information, see the Sun ONE Application Server Developer’s Guide.
The following topics are presented in this chapter:
Web Application StructureWeb Applications have a directory structure, all accessible from a mapping to the application’s document root (for example, /hello). The document root contains JSP files, HTML files, and static files such as image files.
A WAR (web application archive) file contains a complete web application in compressed form.
A special directory under the document root, WEB-INF, contains everything related to the application that is not in the public document tree of the application. No file contained in WEB-INF can be served directly to the client. The contents of WEB-INF include:
- /WEB-INF/classes/*, the directory for servlet and other classes.
- /WEB-INF/lib/*.jar, the directory for JAR files containing beans and other utility classes.
- /WEB-INF/web.xml and /WEB-INF/sun-web.xml, XML-based deployment descriptors that specify the web application configuration, including mappings, initialization parameters, and security constraints.
The web application directory structure follows the structure outlined in the J2EE specification. Here is an example directory structure of a simple web application.
+ hello/
|--- index.jsp
|--+ META-INF/
| |--- MANIFEST.MF
'--+ WEB-INF/
|--- web.xml
'--- sun-web.xml
Here is an example directory structure of a simple J2EE application containing a web module.
Creating Web Deployment DescriptorsSun ONE Application Server web modules include two deployment descriptor files:
- A J2EE standard file (web.xml), described in the Java Servlet Specification, v2.3, Chapter 13, “Deployment Descriptors.” You can find the specification here:
http://java.sun.com/products/servlet/index.html
- An optional Sun ONE Application Server specific file (sun-web.xml), described in this chapter.
The easiest way to create the web.xml and sun-web.xml files is to deploy a web module using the Administration interface or the Sun ONE Studio 4 IDE. For more information, see the next section or the Sun ONE Application Server Developer’s Guide. For example web.xml and sun-web.xml files, see "Sample Web Module XML Files".
After you have created these files, you can edit them using the Sun ONE Studio 4 IDE or a combination of an editor and command line utilities such as Ant to reassemble and redeploy the updated deployment descriptor information. Apache Ant 1.4.1 is provided with Sun ONE Application Server. For more information, see the Sun ONE Application Server Developer’s Guide.
Deploying Web ApplicationsWhen you deploy, undeploy, or redeploy a web application, you do not need to restart the server. In other words, deployment is dynamic.
You can deploy a web application in these ways, which are described briefly:
For more detailed information about deployment, see the Sun ONE Application Server Developer’s Guide.
You can keep the generated source for JSPs by adding the -keepgenerated property to the jsp-config element in sun-web.xml. If you include this property when you deploy the web application, the generated source is kept in instance_dir/generated/jsp/j2ee-apps/app_name/module_name if it is in an application or instance_dir/generated/jsp/j2ee-modules/module_name if it is in an individually deployed web module.
Note
After a web application is undeployed, its HttpSession information is not immediately removed if sessions are persistent. HttpSession information is removed in the subsequent cycle, when timed out sessions are removed. Therefore, you should disable a web application before undeploying it if sessions are persistent.
Using the Command Line
To deploy a web application using the command line:
- Edit the deployment descriptor files (web.xml and sun-web.xml) by hand.
- Execute an Ant build command (such as build war) to reassemble the WAR module.
- Write the web application to a WAR file if desired. This is optional. For example:
jar -cvf module_name.war *
- Use the asadmin deploy command to deploy the WAR module. The syntax is as follows:
asadmin deploy --user admin_user [--password admin_password] [--passwordfile password_file] --host hostname --port adminport [--secure | -s] [--virtualservers virtual_servers] [--type application|ejb|web|connector] [--contextroot contextroot] [--force=true] [--precompilejsp=false] [--verify=false] [--name component_name] [--upload=true] [--retrieve local_dirpath] [--instance instance_name] filepath
For example, the following command deploys a web application as an individual module:
asadmin deploy --user jadams --password secret --host localhost --port 4848 --type web --instance server1 myWebApp.war
If upload is set to false, the filepath must be an absolute path on the server machine.
Using the Administration Interface
To deploy a web application using the Administration interface:
- Open the Applications component under your server instance.
- Go to the Web Applications page.
- Click on the Deploy button.
- Enter the full path to the WAR module (or click on Browse to find it), then click on the OK button.
- Enter the web application name and the context root.
You can also redeploy the web application if it already exists by checking the appropriate box. This is optional.
- Assign the web application to one or more virtual servers by checking the boxes next to the virtual server names.
- Click on the OK button.
Using Sun ONE Studio
You can use Sun ONE Studio 4, to assemble and deploy web applications. For more information about using Sun ONE Studio, see the Sun ONE Studio 4, Enterprise Edition Tutorial.
Note
Sun ONE Studio does not currently support the session persistence attributes related to high availability. To set these attributes, you must edit the sun-web.xml file by hand.
Deploying to a Cluster Using cladmin
If a server instance is part of a cluster, you should deploy the same modules and applications to each instance in the cluster using the cladmin command. For details, see the Sun ONE Application Server Administrator’s Guide.
If you are setting up load balancing, web module context roots must be unique within a cluster. See the Sun ONE Application Server Administrator’s Guide for more information about load balancing.
Dynamic Reloading of Web ApplicationsIf you make code changes to a web application and dynamic reloading is enabled, you do not need to redeploy the web application or restart the server. To enable dynamic reloading, you can do one of the following:
- Use the Administration interface:
- Open the Applications component under your server instance.
- Go to the Applications page.
- Check the Reload Enabled box to enable dynamic reloading.
- Enter a number of seconds in the Reload Poll Interval field to set the interval at which applications and modules are checked for code changes and dynamically reloaded.
- Click on the Save button.
- Go to the server instance page and select the Apply Changes button.
In addition, to load new servlet files, reload EJB related changes, or reload deployment descriptor changes, you must do the following:
For JSPs, changes are reloaded automatically at a frequency set in the reload-interval property of the jsp-config element in the sun-web.xml file. To disable dynamic reloading of JSPs, set the reload-interval property to -1.
The sun-web-app_2_3-0.dtd FileThe sun-web-app_2_3-0.dtd file defines the structure of the sun-web.xml file, including the elements it can contain and the subelements and attributes these elements can have. The sun-web-app_2_3-0.dtd file is located in the install_dir/lib/dtds directory.
Note
Do not edit the sun-web-app_2_3-0.dtd file; its contents change only with new versions of Sun ONE Application Server.
For general information about DTD files and XML, see the XML specification at:
Each element defined in a DTD file (which may be present in the corresponding XML file) can contain the following:
Subelements
Elements can contain subelements. For example, the following file fragment defines the cache element.
<!ELEMENT cache (cache-helper*, default-helper?, property*, cache-mapping*)>
The ELEMENT tag specifies that a cache element can contain cache-helper, default-helper, property, and cache-mapping subelements.
The following table shows how optional suffix characters of subelements determine the requirement rules, or number of allowed occurrences, for the subelements.
Table 6-1 Requirement Rules and Subelement Suffixes
Subelement Suffix
Requirement Rule
element*
Can contain zero or more of this subelement.
element?
Can contain zero or one of this subelement.
element+
Must contain one or more of this subelement.
element (no suffix)
Must contain only one of this subelement.
If an element cannot contain other elements, you see EMPTY or (#PCDATA) instead of a list of element names in parentheses.
Data
Some elements contain character data instead of subelements. These elements have definitions of the following format:
<!ELEMENT element-name (#PCDATA)>
For example:
<!ELEMENT description (#PCDATA)>
In the sun-web.xml file, white space is treated as part of the data in a data element. Therefore, there should be no extra white space before or after the data delimited by a data element. For example:
<description>class name of session manager</description>
Attributes
Elements that have ATTLIST tags contain attributes (name-value pairs). For example:
<!ATTLIST cache max-capacity CDATA "4096"
timeout CDATA "30"
enabled %boolean; "false">A cache element can contain max-capacity, timeout, and enabled attributes.
The #REQUIRED label means that a value must be supplied. The #IMPLIED label means that the attribute is optional, and that Sun ONE Application Server generates a default value. Wherever possible, explicit defaults for optional attributes (such as "true") are listed.
Attribute declarations specify the type of the attribute. For example, CDATA means character data, and %boolean is a predefined enumeration.
Elements in the sun-web.xml FileThis section describes the XML elements in the sun-web.xml file. Elements are grouped as follows:
General Elements
General elements are as follows:
sun-web-app
Defines Sun ONE Application Server specific configuration for a web module. This is the root element; there can only be one sun-web-app element in a sun-web.xml file.
Subelements
The following table describes subelements for the sun-web-app element.
Table 6-2 sun-web-app Subelements
Element
Required
Description
zero or more
Maps roles to users or groups in the currently active realm.
zero or more
Specifies a principal name for a servlet, which is used for the run-as role defined in web.xml.
zero or one
Specifies session manager, session cookie, and other session-related information.
zero or more
Maps the absolute JNDI name to the resource-env-ref in the corresponding J2EE XML file.
zero or more
Maps the absolute JNDI name to the resource-ref in the corresponding J2EE XML file.
zero or more
Maps the absolute JNDI name to the ejb-ref in the corresponding J2EE XML file.
zero or one
Configures caching for web application components.
zero or one
Specifies classloader configuration information.
zero or one
Specifies JSP configuration information.
zero or one
Specifies internationalization settings.
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the sun-web-app element.
Table 6-3 sun-web-app Properties
Property Name
Default Value
Description
crossContextAllowed
true
If true, allows this web application to access the contexts of other web applications using the ServletContext.getContext()method.
tempdir
instance_dir/generated/j2ee-apps/app_name
or
instance_dir/generated/j2ee-modules/module_name
Specifies a temporary directory for use by this web module. This value is used to construct the value of the javax.servlet.context.tempdir context attribute. Compiled JSPs are also placed in this directory.
singleThreadedServletPoolSize
5
Specifies the maximum number of servlet instances allocated for each SingleThreadModel servlet in the web application.
useResponseCTForHeaders
false
If true, header data is sent in the encoding specified in the method Response.setContentType(). Use this property to send non-ASCII characters in the headers.
property
Specifies a property, which has a name and a value. A property adds configuration information to its parent element that is one or both of the following:
For example, a manager-properties element can include property subelements:
<manager-properties>
<property name="reapIntervalSeconds" value="20" />
</manager-properties>Which properties a manager-properties element uses depends on the value of the parent session-manager element’s persistence-type attribute. For details, see the description of the session-manager element.
Subelements
The following table describes subelements for the property element.
Table 6-4 property Subelements
Element
Required
Description
zero or one
Specifies an optional text description of a property.
Attributes
The following table describes attributes for the property element.
Table 6-5 property Attributes
Attribute
Default
Description
name
none
Specifies the name of the property.
value
none
Specifies the value of the property.
description
Contains data that specifies a text description of the containing element.
Subelements
none
Attributes
none
Security Elements
Security elements are as follows:
security-role-mapping
Maps roles to users or groups in the currently active realm. See the Sun ONE Application Server Developer’s Guide for how to define the currently active realm.
Subelements
The following table describes subelements for the security-role-mapping element.
Table 6-6 security-role-mapping Subelements
Element
Required
Description
only one
Contains the role name.
requires at least one principal-name or group-name
Contains a principal (user) name in the current realm.
requires at least one principal-name or group-name
Contains a group name in the current realm.
Attributes
none
servlet
Specifies a principal name for a servlet, which is used for the run-as role defined in web-xml.
Subelements
The following table describes subelements for the servlet element.
Table 6-7 servlet Subelements
Element
Required
Description
only one
Contains the name of a servlet, which is matched to a servlet-name in web.xml.
only one
Contains a principal (user) name in the current realm.
Attributes
none
servlet-name
Contains data that specifies the name of a servlet, which is matched to a servlet-name in web.xml. This name must be present in web.xml.
Subelements
none
Attributes
none
role-name
Contains data that specifies the role-name in the security-role element of the web.xml file.
Subelements
none
Attributes
none
principal-name
Contains data that specifies a principal (user) name in the current realm.
Subelements
none
Attributes
none
group-name
Contains data that specifies a group name in the current realm.
Subelements
none
Attributes
none
Session Elements
Session elements are as follows:
session-config
Specifies session configuration information. Overrides the web container settings for an individual web application.
Subelements
The following table describes subelements for the session-config element.
Table 6-8 session-config Subelements
Element
Required
Description
zero or one
Specifies session manager configuration information.
zero or one
Specifies session properties.
zero or one
Specifies session cookie properties.
Attributes
none
session-manager
Specifies session manager information.
Subelements
The following table describes subelements for the session-manager element.
Table 6-9 session-manager Subelements
Element
Required
Description
zero or one
Specifies session manager properties.
zero or one
Specifies session persistence (storage) properties.
Attributes
The following table describes attributes for the session-manager element.
Table 6-10 session-manager Attributes
Attribute
Default Value
Description
persistence-type
memory
(optional) Specifies the session persistence mechanism. Allowed values are memory, file, and ha.
For production environments that require session persistence, use ha.
The custom value is not implemented and should not be used.
Note
Setting the persistence-type to ha is not sufficient for configuring session persistence. For details, see “Distributed Sessions and Persistence”.
manager-properties
Specifies session manager properties.
Subelements
The following table describes subelements for the manager-properties element.
Table 6-11 manager-properties Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the manager-properties element.
Table 6-12 manager-properties Properties
Property Name
Default Value
Description
reapIntervalSeconds
60
Specifies the number of seconds between checks for expired sessions.
If the persistence-type attribute of the session-manager element is file or ha, sessions are passivated if maxSessions has been exceeded.
If persistenceFrequency is set to time-based, active sessions are stored at this interval.
You should set this value lower than the frequency at which session data changes. For example, this value should be as low as possible (1 second) for a hit counter servlet on a frequently accessed website, or you could lose the last few hits each time you restart the server.
maxSessions
-1
Specifies the maximum number of sessions that can be in cache, or -1 for no limit. After this, an attempt to create a new session causes an IllegalStateException to be thrown.
If the persistence-type attribute of the session-manager element is file or ha, the session manager passivates sessions to the persistent store when this maximum is reached.
sessionFilename
none; state is not preserved across restarts
Specifies the absolute or relative path to the directory in which the session state is preserved between application restarts, if preserving the state is possible. A relative path is relative to the temporary directory for this web application.
Applicable only if the persistence-type attribute of the session-manager element is memory.
persistenceFrequency
web-method
Specifies how often the session state is stored. Allowed values are as follows:
- web-method - The session state is stored at the end of each web request prior to sending a response back to the client. This mode provides the best guarantee that the session state is fully updated in case of failure.
- time-based - The session state is stored in the background at the frequency set by reapIntervalSeconds. This mode provides less of a guarantee that the session state is fully updated. However, it can provide a significant performance improvement because the state is not stored after each request.
Applicable only if the persistence-type attribute of the session-manager element is ha.
store-properties
Specifies session persistence (storage) properties.
Subelements
The following table describes subelements for the store-properties element.
Table 6-13 store-properties Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the store-properties element.
Table 6-14 store-properties Properties
Property Name
Default Value
Description
directory
instance_dir/generated/jsp/j2ee-apps/appname/appname_war
Specifies the absolute or relative pathname of the directory into which individual session files are written. A relative path is relative to the temporary work directory for this web application.
Applicable only if the persistence-type attribute of the session-manager element is file.
persistenceScope
session
Specifies how much of the session state is stored. Allowed values are as follows:
- session - The entire session state is stored every time. This mode provides the best guarantee that your session data is correctly stored for any distributable web application.
- modified-session - The entire session state is stored if it has been modified. A session is considered to have been modified if HttpSession.setAttribute() or HttpSession.removeAttribute() was called. You must guarantee that setAttribute() is called every time an attribute is changed. This is not a J2EE specification requirement, but it is required for this mode to work properly.
- modified-attribute - Only modified session attributes are stored. For this mode to work properly, you must follow some guidelines, which are explained immediately following this table.
Applicable only if the persistence-type attribute of the session-manager element is ha.
If the persistenceScope store property is set to modified-attribute, your web application must follow these guidelines:
- Call setAttribute() every time you modify the session state.
- Make sure there are no cross-references between attributes. The object graph under each distinct attribute key is serialized and stored separately. If there are any object cross references between the objects under each separate key, they are not serialized and deserialized correctly.
- Distribute the session state across multiple attributes, or at least between a read-only attribute and a modifiable attribute.
Note
The session persistence scope modified-attribute is not certified as a full production quality feature. You should evaluate the performance and stability of the web container under expected peak load with this persistence scope. If exceptions are logged or response time is too high, do not use this persistence scope for your production environment. Use session or modified-session instead.
session-properties
Specifies session properties.
Subelements
The following table describes subelements for the session-properties element.
Table 6-15 session-properties Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the session-properties element.
Table 6-16 session-properties Properties
Property Name
Default Value
Description
timeoutSeconds
600
Specifies the default maximum inactive interval (in seconds) for all sessions created in this web module. If set to 0 or less, sessions in this web module never expire.
If a session-timeout element is specified in the web.xml file, the session-timeout value overrides any timeoutSeconds value. If neither session-timeout nor timeoutSeconds is specified, the timeoutSeconds default is used.
Note that the session-timeout element in web.xml is specified in minutes, not seconds.
enableCookies
true
Uses cookies for session tracking if set to true.
enableURLRewriting
true
Enables URL rewriting. This provides session tracking via URL rewriting when the browser does not accept cookies. You must also use an encodeURL or encodeRedirectURL call in the servlet or JSP.
idLengthBytes
128
Specifies the number of bytes in this web module’s session ID.
cookie-properties
Specifies session cookie properties.
Subelements
The following table describes subelements for the cookie-properties element.
Table 6-17 cookie-properties Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the cookie-properties element.
Table 6-18 cookie-properties Properties
Property Name
Default Value
Description
cookieName
JSESSIONID
Specifies the name of the cookie used for session tracking.
cookiePath
Context path at which the web module is installed.
Specifies the pathname that is set when the cookie is created. The browser sends the cookie if the pathname for the request contains this pathname. If set to / (slash), the browser sends cookies to all URLs served by the Sun ONE Application Server. You can set the path to a narrower mapping to limit the request URLs to which the browser sends cookies.
cookieMaxAgeSeconds
-1
Specifies the expiration time (in seconds) after which the browser expires the cookie.
cookieDomain
(unset)
Specifies the domain for which the cookie is valid.
cookieComment
Sun ONE Application Server Session Tracking Cookie
Specifies the comment that identifies the session tracking cookie in the cookie file. Applications can provide a more specific comment for the cookie.
Reference Elements
Reference elements are as follows:
Note
If a distributable web application references a component, and the web application’s session fails over, the reference may be lost. For information about how to work around this limitation, see “Distributed Sessions and Persistence” and the Sun ONE Application Server Application Design Guidelines for Storing Session State.
resource-env-ref
Maps the res-ref-name in the corresponding J2EE web.xml file resource-env-ref entry to the absolute jndi-name of a resource.
Subelements
The following table describes subelements for the resource-env-ref element.
Table 6-19 resource-env-ref Subelements
Element
Required
Description
only one
Specifies the res-ref-name in the corresponding J2EE web.xml file resource-env-ref entry.
only one
Specifies the absolute jndi-name of a resource.
Attributes
none
resource-env-ref-name
Contains data that specifies the res-ref-name in the corresponding J2EE web.xml file resource-env-ref entry.
Subelements
none
Attributes
none
resource-ref
Maps the res-ref-name in the corresponding J2EE web.xml file resource-ref entry to the absolute jndi-name of a resource.
Subelements
The following table describes subelements for the resource-ref element.
Table 6-20 resource-ref Subelements
Element
Required
Description
only one
Specifies the res-ref-name in the corresponding J2EE web.xml file resource-ref entry.
only one
Specifies the absolute jndi-name of a resource.
zero or one
Specifies the default principal (user) for the resource.
Attributes
none
res-ref-name
Contains data that specifies the res-ref-name in the corresponding J2EE web.xml file resource-ref entry.
Subelements
none
Attributes
none
default-resource-principal
Specifies the default principal (user) for the resource.
If this element is used in conjunction with a JMS Connection Factory resource, the name and password subelements must be valid entries in the Sun™ Open Net Environment (Sun ONE) Message Queue broker user repository. See the “Security Management” chapter in the Sun ONE Message Queue Administrator’s Guide for details.
Subelements
The following table describes subelements for the default-resource-principal element.
Table 6-21 default-resource-principal Subelements
Element
Required
Description
only one
Contains the name of the principal.
only one
Contains the password for the principal.
Attributes
none
name
Contains data that specifies the name of the principal.
Subelements
none
Attributes
none
password
Contains data that specifies the password for the principal.
Subelements
none
Attributes
none
ejb-ref
Maps the ejb-ref-name in the corresponding J2EE ejb-jar.xml file ejb-ref entry to the absolute jndi-name of a resource.
Subelements
The following table describes subelements for the ejb-ref element.
Table 6-22 ejb-ref Subelements
Element
Required
Description
only one
Specifies the ejb-ref-name in the corresponding J2EE ejb-jar.xml file ejb-ref entry.
only one
Specifies the absolute jndi-name of a resource.
Attributes
none
ejb-ref-name
Contains data that specifies the ejb-ref-name in the corresponding J2EE ejb-jar.xml file ejb-ref entry.
Subelements
none
Attributes
none
jndi-name
Contains data that specifies the absolute jndi-name of a URL resource or a resource in the server.xml file.
Note
To avoid collisions with names of other enterprise resources in JNDI, and to avoid portability problems, all names in a Sun ONE Application Server application should begin with the string java:comp/env.
Subelements
none
Attributes
none
Caching Elements
For details about response caching as it pertains to servlets, see “Caching Servlet Results”. For details about JSP caching, see “JSP Caching”.
Caching elements are as follows:
cache
Configures caching for web application components.
Subelements
The following table describes subelements for the cache element.
Table 6-23 cache Subelements
Element
Required
Description
zero or more
Specifies a custom class that implements the CacheHelper interface.
zero or one
Allows you to change the properties of the default, built-in cache-helper class.
zero or more
Specifies a cache property, which has a name and a value.
zero or more
Maps a URL pattern or a servlet name to its cacheability constraints.
Attributes
The following table describes attributes for the cache element.
Table 6-24 cache Attributes
Attribute
Default Value
Description
max-entries
4096
(optional) Specifies the maximum number of entries the cache can contain. Must be a positive integer.
timeout-in-seconds
30
(optional) Specifies the maximum amount of time in seconds that an entry can remain in the cache after it is created or refreshed. Can be overridden by a timeout element.
enabled
false
(optional) Determines whether servlet and JSP caching is enabled. Legal values are on, off, yes, no, 1, 0, true, false.
Properties
The following table describes properties for the cache element.
Table 6-25 cache Properties
Property
Default Value
Description
cacheClassName
com.sun.appserv.web.cache.LruCache
Specifies the fully qualified name of the class that implements the cache functionality. The "cacheClassName Values" table below lists possible values.
MultiLRUSegmentSize
4096
Specifies the number of entries in a segment of the cache table that should have its own LRU (least recently used) list. Applicable only if cacheClassName is set to com.sun.appserv.web.cache.MultiLruCache.
MaxSize
unlimited; Long.MAX_VALUE
Specifies an upper bound on the cache memory size in bytes (KB or MB units). Example values are 32 KB or 2 MB. Applicable only if cacheClassName is set to com.sun.appserv.web.cache.BoundedMultiLruCache.
Cache Class Names
The following table lists possible values of the cacheClassName property.
Table 6-26 cacheClassName Values
Value
Description
com.sun.appserv.web.cache.LruCache
A bounded cache with an LRU (least recently used) cache replacement policy.
com.sun.appserv.web.cache.BaseCache
An unbounded cache suitable if the maximum number of entries is known.
com.sun.appserv.web.cache.MultiLruCache
A cache suitable for a large number of entries (>4096). Uses the MultiLRUSegmentSize property.
com.sun.appserv.web.cache.BoundedMultiLruCache
A cache suitable for limiting the cache size by memory rather than number of entries. Uses the MaxSize property.
cache-helper
Specifies a class that implements the CacheHelper interface. For details, see “CacheHelper Interface”.
Subelements
The following table describes subelements for the cache-helper element.
Table 6-27 cache-helper Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
The following table describes attributes for the cache-helper element.
Table 6-28 cache-helper Attributes
Attribute
Default Value
Description
name
default
Specifies a unique name for the helper class, which is referenced in the cache-mapping element.
class-name
none
Specifies the fully qualified class name of the cache helper, which must implement the com.sun.appserv.web.CacheHelper interface.
default-helper
Allows you to change the properties of the built-in default cache-helper class.
Subelements
The following table describes subelements for the default-helper element.
Table 6-29 default-helper Subelements
Element
Required
Description
zero or more
Specifies a property, which has a name and a value.
Attributes
none
Properties
The following table describes properties for the default-helper element.
Table 6-30 default-helper Properties
Property
Default Value
Description
cacheKeyGeneratorAttrName
Uses the built-in default cache-helper key generation, which concatenates the servlet path with key-field values, if any.
The caching engine looks in the ServletContext for an attribute with a name equal to the value specified for this property to determine whether a customized CacheKeyGenerator implementation is used. An application may provide a customized key generator rather than using the default helper.
cache-mapping
Maps a URL pattern or a servlet name to its cacheability constraints.
Subelements
The following table describes subelements for the cache-mapping element.
Table 6-31 cache-mapping Subelements
Element
Required
Description
requires one servlet-name or url-pattern
Contains the name of a servlet.
requires one servlet-name or url-pattern
Contains a servlet URL pattern for which caching is enabled.
required if timeout, refresh-field, http-method, key-field, and constraint-field are not used
Contains the name of the cache-helper used by the parent cache-mapping element.
zero or one if cache-helper-ref is not used
Contains the cache-mapping specific maximum amount of time in seconds that an entry can remain in the cache after it is created or refreshed.
zero or one if cache-helper-ref is not used
Specifies a field that gives the application component a programmatic way to refresh a cached entry.
zero or more if cache-helper-ref is not used
Contains an HTTP method that is eligible for caching.
zero or more if cache-helper-ref is not used
Specifies a component of the key used to look up and extract cache entries.
zero or more if cache-helper-ref is not used
Specifies a cacheability constraint for the given url-pattern or servlet-name.
Attributes
none
url-pattern
Contains data that specifies a servlet URL pattern for which caching is enabled. See the Servlet 2.3 specification section SRV. 11.2 for applicable patterns.
Subelements
none
Attributes
none
cache-helper-ref
Contains data that specifies the name of the cache-helper used by the parent cache-mapping element.
Subelements
none
Attributes
none
timeout
Contains data that specifies the cache-mapping specific maximum amount of time in seconds that an entry can remain in the cache after it is created or refreshed. If not specified, the default is the value of the timeout attribute of the cache element.
Subelements
none
Attributes
The following table describes attributes for the timeout element.
Table 6-32 timeout Attributes
Attribute
Default Value
Description
name
none
Specifies the timeout input parameter, whose value is interpreted in seconds. The field’s type must be java.lang.Long or java.lang.Integer.
scope
request.attribute
(optional) Specifies the scope in which the input parameter can be present. Allowed values are context.attribute, request.header, request.parameter, request.cookie, request.attribute, and session.attribute.
refresh-field
Specifies a field that gives the application component a programmatic way to refresh a cached entry.
Subelements
none
Attributes
The following table describes attributes for the refresh-field element.
Table 6-33 refresh-field Attributes
Attribute
Default Value
Description
name
none
Specifies the input parameter name.
scope
request.parameter
(optional) Specifies the scope in which the input parameter can be present. Allowed values are context.attribute, request.header, request.parameter, request.cookie, session.id, and session.attribute.
http-method
Contains data that specifies an HTTP method that is eligible for caching. The default is GET.
Subelements
none
Attributes
none
key-field
Specifies a component of the key used to look up and extract cache entries. The web container looks for the named parameter, or field, in the specified scope.
If this element is not present, the web container uses the Servlet Path (the path section that corresponds to the servlet mapping that activated the current request). See the Servlet 2.3 specification, section SRV 4.4, for details on the Servlet Path.
Subelements
none
Attributes
The following table describes attributes for the key-field element.
Table 6-34 key-field Attributes
Attribute
Default Value
Description
name
none
Specifies the input parameter name.
scope
request.parameter
(optional) Specifies the scope in which the input parameter can be present. Allowed values are context.attribute, request.header, request.parameter, request.cookie, session.id, and session.attribute.
constraint-field
Specifies a cacheability constraint for the given url-pattern or servlet-name.
All constraint-field constraints must pass for a response to be cached. If there are value constraints, at least one of them must pass.
Subelements
The following table describes subelements for the constraint-field element.
Table 6-35 constraint-field Subelements
Element
Required
Description
zero or more
Contains a value to be matched to the input parameter value.
Attributes
The following table describes attributes for the constraint-field element.
Table 6-36 constraint-field Attributes
Attribute
Default Value
Description
name
none
Specifies the input parameter name.
scope
request.parameter
(optional) Specifies the scope in which the input parameter can be present. Allowed values are context.attribute, request.header, request.parameter, request.cookie, request.attribute, and session.attribute.
cache-on-match
true
(optional) If true, caches the response if matching succeeds. Overrides the same attribute in a value subelement.
cache-on-match-failure
false
(optional) If true, caches the response if matching fails. Overrides the same attribute in a value subelement.
value
Contains data that specifies a value to be matched to the input parameter value. The matching is case sensitive. For example:
<value match-expr="in-range">1-60</value>
Subelements
none
Attributes
The following table describes attributes for the value element.
Table 6-37 value Attributes
Attribute
Default Value
Description
match-expr
equals
(optional) Specifies the type of comparison performed with the value. Allowed values are equals, not-equals, greater, lesser, and in-range.
If match-expr is greater or lesser, the value must be a number. If match-expr is in-range, the value must be of the form n1-n2, where n1 and n2 are numbers.
cache-on-match
true
(optional) If true, caches the response if matching succeeds.
cache-on-match-failure
false
(optional) If true, caches the response if matching fails.
Classloader Elements
Classloader elements are as follows:
class-loader
Configures the classloader for the web module.
Subelements
none
Attributes
The following table describes attributes for the class-loader element.
Table 6-38 class-loader Attributes
Attribute
Default Value
Description
extra-class-path
null
(optional) Specifies additional classpath settings for this web module.
delegate
false
(optional) If true, the web module follows the standard classloader delegation model and delegates to its parent classloader first before looking in the local classloader. If false, the web module follows the delegation model specified in the Servlet specification and looks in its classloader before looking in the parent classloader.
For a web component of a web service, you must set this value to true.
Legal values are on, off, yes, no, 1, 0, true, false.
Note
If the delegate flag is set to its default value of false, the classloader delegation behavior complies with the Servlet 2.3 specification, section 9.7.2. If set to true, classes and resources residing in container-wide library JAR files are loaded in preference to classes and resources packaged within the WAR file, contrary to what this specification recommends.
Portable programs that use this flag should not be packaged with any classes or interfaces that are a part of the J2EE specification. The behavior of a program that includes such classes or interfaces in its WAR file is undefined.
JSP Elements
JSP elements are as follows:
jsp-config
Specifies JSP configuration information.
Subelements
The following table describes subelements for the jsp-config element.
Attributes
none
Properties
The following table describes properties for the jsp-config element.
Table 6-40 jsp-config Properties
Property Name
Default Value
Description
ieClassId
clsid:8AD9C840-044E-11D1-B3E9-00805F499D93
The Java plug-in COM class ID for Internet Explorer. Used by the <jsp:plugin> tags.
javaCompilerPlugin
The internal JDK compiler (javac)
The fully qualified class name of the Java compiler plug-in to be used. Not needed for the default compiler.
For example, to use the jikes compiler for JSP pages, set the javaCompilerPlugin property to org.apache.jasper.compiler.JikesJavaCompiler, then set the javaCompilerPath property to point to the jikes executable.
javaCompilerPath
none
Specifies the path to the executable of an out-of-process Java compiler such as jikes. Ignored for the default compiler. Needed only if the javaCompilerPlugin property is specified.
javaEncoding
UTF8
Specifies the encoding for the generated Java servlet. This encoding is passed to the Java compiler used to compile the servlet as well. By default, the web container tries to use UTF8. If that fails, it tries to use the javaEncoding value.
For encodings you can use, see:
http://java.sun.com/j2se/1.4/docs/guide/intl/ encoding.doc.html
classdebuginfo
false
Specifies whether the generated Java servlets should be compiled with the debug option set (-g for javac).
keepgenerated
true
If set to true, keeps the generated Java files. If false, deletes the Java files.
largefile
false
If set to true, static HTML is stored is a separate data file when a JSP is compiled. This is useful when a JSP is very large, because it minimizes the size of the generated servlet.
mappedfile
false
If set to true, generates separate write calls for each HTML line and comments that describe the location of each line in the JSP file. By default, all adjacent write calls are combined and no location comments are generated.
scratchdir
The default work directory for the web application
The working directory created for storing all the generated code.
reload-interval
0
Specifies the frequency (in seconds) at which JSP files are checked for modifications. Setting this value to 0 checks JSPs for modifications on every request. Setting this value to -1 disables checks for JSP modifications and JSP recompilation.
Internationalization Elements
Internationalization elements are as follows:
locale-charset-info
Specifies information about the application’s internationalization settings.
Subelements
The following table describes subelements for the locale-charset-info element.
Table 6-41 locale-charset-info Subelements
Element
Required
Description
one or more
Maps a locale and an agent to a character set.
zero or one
Determines how the web container decodes parameters from forms for this web application according to a hidden field value.
Attributes
The following table describes attributes for the locale-charset-info element.
Table 6-42 locale-charset-info Attributes
Attribute
Default Value
Description
default-locale
none
Specifies the default locale.
locale-charset-map
Maps locales and agents to character sets.
For encodings you can use, see:
http://java.sun.com/j2se/1.4/docs/guide/intl/encoding.doc.html
Subelements
The following table describes subelements for the locale-charset-map element.
Table 6-43 locale-charset-map Subelements
Element
Required
Description
zero or one
Specifies an optional text description of a mapping.
Attributes
The following table describes attributes for the locale-charset-map element.
Table 6-44 locale-charset-map Attributes
Attribute
Default Value
Description
locale
none
Specifies the locale name.
agent
none
(optional) Specifies the type of client that interacts with the application server. For a given locale, different agents may have different preferred character sets. The value of this attribute must exactly match the value of the user-agent HTTP request header sent by the client. See the "Example agent Attribute Values" table for more information.
charset
none
Specifies the character set.
Example Agents
The following table specifies example agent attribute values.
Table 6-45 Example agent Attribute Values
Agent
user-agent Header and agent Attribute Value
Netscape 4.7 for Solaris
Mozilla/4.7 [en] (X11; u; Sun OS 5.6 sun4u)
parameter-encoding
Specifies a hidden field that determines the character encoding the web container uses to decode parameters for request.getParameter calls when the charset is not set in the request’s content-type. For encodings you can use, see:
http://java.sun.com/j2se/1.4/docs/guide/intl/encoding.doc.html
Subelements
none
Attributes
The following table describes attributes for the parameter-encoding element.
Table 6-46 parameter-encoding Attributes
Attribute
Default Value
Description
form-hint-field
none
The name of the hidden field in the form that specifies the parameter encoding.
Sample Web Module XML FilesThis section includes the following:
Sample web.xml File
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC '-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN' 'http://java.sun.com/j2ee/dtds/web-app_2_2.dtd'>
<web-app>
<display-name>webapps-simple</display-name>
<description>
The jakarta-tomcat-4.0.3 sample apps ports over to S1AS.
</description>
<distributable></distributable>
<servlet>
<servlet-name>HelloWorldExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.HelloWorldExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestHeaderExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.RequestHeaderExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>SnoopServlet</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.SnoopServlet
</servlet-class>
</servlet>
<servlet>
<servlet-name>servletToJsp</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.servletToJsp
</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestInfoExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.RequestInfoExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>SessionExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.SessionExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>CookieExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.CookieExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>RequestParamExample</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.RequestParamExample
</servlet-class>
</servlet>
<servlet>
<servlet-name>SendMailServlet</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.SendMailServlet
</servlet-class>
</servlet>
<servlet>
<servlet-name>JndiServlet</servlet-name>
<servlet-class>
samples.webapps.simple.servlet.JndiServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldExample</servlet-name>
<url-pattern>/helloworld</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestHeaderExample</servlet-name>
<url-pattern>/requestheader</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>SnoopServlet</servlet-name>
<url-pattern>/snoop</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>servletToJsp</servlet-name>
<url-pattern>/servletToJsp</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestInfoExample</servlet-name>
<url-pattern>/requestinfo</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>SessionExample</servlet-name>
<url-pattern>/session</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>CookieExample</servlet-name>
<url-pattern>/cookie</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RequestParamExample</servlet-name>
<url-pattern>/requestparam</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>SendMailServlet</servlet-name>
<url-pattern>/SendMailServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>JndiServlet</servlet-name>
<url-pattern>/JndiServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<taglib>
<taglib-uri>
http://java.apache.org/tomcat/examples-taglib
</taglib-uri>
<taglib-location>
/WEB-INF/tlds/example-taglib.tld
</taglib-location>
</taglib>
<resource-ref>
<res-ref-name>mail/Session</res-ref-name>
<res-type>javax.mail.Session</res-type>
<res-auth>Container</res-auth>
</resource-ref>
<security-constraint>
<web-resource-collection>
<web-resource-name>Protected Area</web-resource-name>
<!-- Define the context-relative URL(s) to be protected -->
<url-pattern>/jsp/security/protected/*</url-pattern>
<!-- If you list http methods, only those methods are protected -->
<http-method>DELETE</http-method>
<http-method>GET</http-method>
<http-method>POST</http-method>
<http-method>PUT</http-method>
</web-resource-collection>
<auth-constraint>
<!-- Anyone with one of the listed roles may access this area -->
<role-name>tomcat</role-name>
<role-name>role1</role-name>
</auth-constraint>
</security-constraint>
<!-- Environment entry examples -->
<env-entry>
<description>
The maximum number of tax exemptions allowed to be set.
</description>
<env-entry-name>maxExemptions</env-entry-name>
<env-entry-value>15</env-entry-value>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>minExemptions</env-entry-name>
<env-entry-value>1</env-entry-value>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>foo/name1</env-entry-name>
<env-entry-value>value1</env-entry-value>
<env-entry-type>java.lang.String</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>foo/bar/name2</env-entry-name>
<env-entry-value>true</env-entry-value>
<env-entry-type>java.lang.Boolean</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>name3</env-entry-name>
<env-entry-value>1</env-entry-value>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>foo/name4</env-entry-name>
<env-entry-value>10</env-entry-value>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry>
</web-app>
Sample sun-web.xml File
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sun-web-app PUBLIC '-//Sun Microsystems, Inc.//DTD Sun ONE Application Server 7.0 Servlet 2.3//EN' 'http://www.sun.com/software/sunone/appserver/dtds/sun-web-app_2_3- 0.dtd'>
<sun-web-app>
<session-config>
<session-manager/>
</session-config>
<resource-ref>
<res-ref-name>mail/Session</res-ref-name>
<jndi-name>mail/Session</jndi-name>
</resource-ref>
<jsp-config/>
</sun-web-app>
