WebUtils

Prefix of the charset clause in a content type String: ";charset="

Default character encoding to use when request.getCharacterEncoding returns null, according to the Servlet spec.

Default web app root key: "webapp.root"

Standard Servlet 2.3+ spec request attributes for error pages.

To be exposed to JSPs that are marked as error pages, when forwarding to them directly rather than through the servlet container's error page resolution mechanism.

Standard Servlet 2.4+ spec request attributes for forward URI and paths.

If forwarded to via a RequestDispatcher, the current resource will see its own URI and paths. The originating URI and paths are exposed as request attributes.

HTML escape parameter at the servlet context level (i.e. a context-param in web.xml): "defaultHtmlEscape".

Standard Servlet 2.3+ spec request attributes for include URI and paths.

If included via a RequestDispatcher, the current resource will see the originating request. Its own URI and paths are exposed as request attributes.

Standard Servlet spec context attribute that specifies a temporary directory for the current web application, of type java.io.File.

Web app root key parameter at the servlet context level (i.e. a context-param in web.xml): "webAppRootKey".

Key for the mutex session attribute

Name suffixes in case of image buttons

Clear the Servlet spec's error attributes as javax.servlet.http.HttpServletRequest attributes under the keys defined in the Servlet 2.3 specification: javax.servlet.error.status_code, javax.servlet.error.exception_type, javax.servlet.error.message, javax.servlet.error.exception, javax.servlet.error.request_uri, javax.servlet.error.servlet_name.

Expose the Servlet spec's error attributes as javax.servlet.http.HttpServletRequest attributes under the keys defined in the Servlet 2.3 specification, for error pages that are rendered directly rather than through the Servlet container's error page resolution: javax.servlet.error.status_code, javax.servlet.error.exception_type, javax.servlet.error.message, javax.servlet.error.exception, javax.servlet.error.request_uri, javax.servlet.error.servlet_name.

Does not override values if already present, to respect attribute values that have been exposed explicitly before.

Exposes status code 200 by default. Set the "javax.servlet.error.status_code" attribute explicitly (before or after) in order to expose a different status code.

Expose the current request URI and paths as javax.servlet.http.HttpServletRequest attributes under the keys defined in the Servlet 2.4 specification, for containers that implement 2.3 or an earlier version of the Servlet API: javax.servlet.forward.request_uri, javax.servlet.forward.context_path, javax.servlet.forward.servlet_path, javax.servlet.forward.path_info, javax.servlet.forward.query_string.

Does not override values if already present, to not cause conflicts with the attributes exposed by Servlet 2.4+ containers themselves.

Expose the given Map as request attributes, using the keys as attribute names and the values as corresponding attribute values. Keys need to be Strings.

Extract the URL filename from the given request URL path. Correctly resolves nested paths such as "/products/view.html" as well.

Extract the full URL filename (including file extension) from the given request URL path. Correctly resolves nested paths such as "/products/view.html" as well.

Obtain a named parameter from the given request parameters.

See findParameterValue(java.util.Map, String) for a description of the lookup algorithm.

Obtain a named parameter from the given request parameters.

This method will try to obtain a parameter value using the following algorithm:

1. Try to get the parameter value using just the given logical name. This handles parameters of the form logicalName = value. For normal parameters, e.g. submitted using a hidden HTML form field, this will return the requested value.
2. Try to obtain the parameter value from the parameter name, where the parameter name in the request is of the form logicalName_value = xyz with "_" being the configured delimiter. This deals with parameter values submitted using an HTML form submit button.
3. If the value obtained in the previous step has a ".x" or ".y" suffix, remove that. This handles cases where the value was submitted using an HTML form image button. In this case the parameter in the request would actually be of the form logicalName_value.x = 123.

Retrieve the first cookie with the given name. Note that multiple cookies can have the same name but different paths or domains.

Return whether default HTML escaping is enabled for the web application, i.e. the value of the "defaultHtmlEscape" context-param in web.xml (if any).

This method differentiates between no param specified at all and an actual boolean value specified, allowing to have a context-specific default in case of no setting at the global level.

Return an appropriate request object of the specified type, if available, unwrapping the given request as far as necessary.

Return an appropriate response object of the specified type, if available, unwrapping the given response as far as necessary.

Get the specified session attribute, creating and setting a new attribute if no existing found. The given class needs to have a public no-arg constructor. Useful for on-demand state objects in a web tier, like shopping carts.

Return a map containing all parameters with the given prefix. Maps single values to String and multiple values to String array.

For example, with a prefix of "spring_", "spring_param1" and "spring_param2" result in a Map with "param1" and "param2" as keys.

Return the real path of the given path within the web application, as provided by the servlet container.

Prepends a slash if the path does not already start with a slash, and throws a FileNotFoundException if the path cannot be resolved to a resource (in contrast to ServletContext's getRealPath, which returns null).

Check the given request for a session attribute of the given name. Throws an exception if there is no session or if the session has no such attribute. Does not create a new session if none has existed before!

Check the given request for a session attribute of the given name. Returns null if there is no session or if the session has no such attribute. Does not create a new session if none has existed before!

Determine the session id of the given request, if any.

Return the best available mutex for the given session: that is, an object to synchronize on for the given session.

Returns the session mutex attribute if available; usually, this means that the HttpSessionMutexListener needs to be defined in web.xml. Falls back to the HttpSession itself if no mutex attribute found.

The session mutex is guaranteed to be the same object during the entire lifetime of the session, available under the key defined by the SESSION_MUTEX_ATTRIBUTE constant. It serves as a safe reference to synchronize on for locking on the current session.

In many cases, the HttpSession reference itself is a safe mutex as well, since it will always be the same object reference for the same active logical session. However, this is not guaranteed across different servlet containers; the only 100% safe way is a session mutex.

Return the target page specified in the request.

Return the temporary directory for the current web application, as provided by the servlet container.

Check if a specific input type="submit" parameter was sent in the request, either via a button (directly with name) or via an image (name + ".x" or name + ".y").

Return whether default HTML escaping is enabled for the web application, i.e. the value of the "defaultHtmlEscape" context-param in web.xml (if any). Falls back to false in case of no explicit default given.

Determine whether the given request is an include request, that is, not a top-level HTTP request coming in from the outside.

Checks the presence of the "javax.servlet.include.request_uri" request attribute. Could check any request attribute that is only present in an include request.

Remove the system property that points to the web app root directory. To be called on shutdown of the web application.

Set the session attribute with the given name to the given value. Removes the session attribute if value is null, if a session existed at all. Does not create a new session if not necessary!

Set a system property to the web application root directory. The key of the system property can be defined with the "webAppRootKey" context-param in web.xml. Default is "webapp.root".

Can be used for tools that support substition with System.getProperty values, like log4j's "${key}" syntax within log file locations.