public abstract class WebUtils extends Object
Modifier and Type | Field and Description |
---|---|
static String |
CONTENT_TYPE_CHARSET_PREFIX
Prefix of the charset clause in a content type String: ";charset="
|
static String |
DEFAULT_CHARACTER_ENCODING
Default character encoding to use when
request.getCharacterEncoding
returns null , according to the Servlet spec. |
static String |
DEFAULT_WEB_APP_ROOT_KEY
Default web app root key: "webapp.root"
|
static String |
ERROR_EXCEPTION_ATTRIBUTE |
static String |
ERROR_EXCEPTION_TYPE_ATTRIBUTE |
static String |
ERROR_MESSAGE_ATTRIBUTE |
static String |
ERROR_REQUEST_URI_ATTRIBUTE |
static String |
ERROR_SERVLET_NAME_ATTRIBUTE |
static String |
ERROR_STATUS_CODE_ATTRIBUTE
Standard Servlet 2.3+ spec request attributes for error pages.
|
static String |
FORWARD_CONTEXT_PATH_ATTRIBUTE |
static String |
FORWARD_PATH_INFO_ATTRIBUTE |
static String |
FORWARD_QUERY_STRING_ATTRIBUTE |
static String |
FORWARD_REQUEST_URI_ATTRIBUTE
Standard Servlet 2.4+ spec request attributes for forward URI and paths.
|
static String |
FORWARD_SERVLET_PATH_ATTRIBUTE |
static String |
HTML_ESCAPE_CONTEXT_PARAM
HTML escape parameter at the servlet context level
(i.e.
|
static String |
INCLUDE_CONTEXT_PATH_ATTRIBUTE |
static String |
INCLUDE_PATH_INFO_ATTRIBUTE |
static String |
INCLUDE_QUERY_STRING_ATTRIBUTE |
static String |
INCLUDE_REQUEST_URI_ATTRIBUTE
Standard Servlet 2.3+ spec request attributes for include URI and paths.
|
static String |
INCLUDE_SERVLET_PATH_ATTRIBUTE |
static String |
SESSION_MUTEX_ATTRIBUTE
Key for the mutex session attribute
|
static String[] |
SUBMIT_IMAGE_SUFFIXES
Name suffixes in case of image buttons
|
static String |
TEMP_DIR_CONTEXT_ATTRIBUTE
Standard Servlet spec context attribute that specifies a temporary
directory for the current web application, of type
java.io.File . |
static String |
WEB_APP_ROOT_KEY_PARAM
Web app root key parameter at the servlet context level
(i.e.
|
Constructor and Description |
---|
WebUtils() |
Modifier and Type | Method and Description |
---|---|
static void |
clearErrorRequestAttributes(HttpServletRequest request)
Clear the Servlet spec's error attributes as
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 . |
static void |
exposeErrorRequestAttributes(HttpServletRequest request,
Throwable ex,
String servletName)
Expose the Servlet spec's error attributes as
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 . |
static void |
exposeForwardRequestAttributes(HttpServletRequest request)
Expose the current request URI and paths as
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 . |
static void |
exposeRequestAttributes(ServletRequest request,
Map<String,?> attributes)
Expose the given Map as request attributes, using the keys as attribute names
and the values as corresponding attribute values.
|
static String |
extractFilenameFromUrlPath(String urlPath)
Extract the URL filename from the given request URL path.
|
static String |
extractFullFilenameFromUrlPath(String urlPath)
Extract the full URL filename (including file extension) from the given request URL path.
|
static String |
findParameterValue(Map<String,?> parameters,
String name)
Obtain a named parameter from the given request parameters.
|
static String |
findParameterValue(ServletRequest request,
String name)
Obtain a named parameter from the given request parameters.
|
static Cookie |
getCookie(HttpServletRequest request,
String name)
Retrieve the first cookie with the given name.
|
static Boolean |
getDefaultHtmlEscape(ServletContext servletContext)
Return whether default HTML escaping is enabled for the web application,
i.e.
|
static <T> T |
getNativeRequest(ServletRequest request,
Class<T> requiredType)
Return an appropriate request object of the specified type, if available,
unwrapping the given request as far as necessary.
|
static <T> T |
getNativeResponse(ServletResponse response,
Class<T> requiredType)
Return an appropriate response object of the specified type, if available,
unwrapping the given response as far as necessary.
|
static Object |
getOrCreateSessionAttribute(HttpSession session,
String name,
Class<?> clazz)
Get the specified session attribute, creating and setting a new attribute if
no existing found.
|
static Map<String,Object> |
getParametersStartingWith(ServletRequest request,
String prefix)
Return a map containing all parameters with the given prefix.
|
static String |
getRealPath(ServletContext servletContext,
String path)
Return the real path of the given path within the web application,
as provided by the servlet container.
|
static Object |
getRequiredSessionAttribute(HttpServletRequest request,
String name)
Check the given request for a session attribute of the given name.
|
static Object |
getSessionAttribute(HttpServletRequest request,
String name)
Check the given request for a session attribute of the given name.
|
static String |
getSessionId(HttpServletRequest request)
Determine the session id of the given request, if any.
|
static Object |
getSessionMutex(HttpSession session)
Return the best available mutex for the given session:
that is, an object to synchronize on for the given session.
|
static int |
getTargetPage(ServletRequest request,
String paramPrefix,
int currentPage)
Return the target page specified in the request.
|
static File |
getTempDir(ServletContext servletContext)
Return the temporary directory for the current web application,
as provided by the servlet container.
|
static boolean |
hasSubmitParameter(ServletRequest request,
String name)
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").
|
static boolean |
isDefaultHtmlEscape(ServletContext servletContext)
Return whether default HTML escaping is enabled for the web application,
i.e.
|
static boolean |
isIncludeRequest(ServletRequest request)
Determine whether the given request is an include request,
that is, not a top-level HTTP request coming in from the outside.
|
static MultiValueMap<String,String> |
parseMatrixVariables(String matrixVariables)
Parse the given string with matrix variables.
|
static void |
removeWebAppRootSystemProperty(ServletContext servletContext)
Remove the system property that points to the web app root directory.
|
static void |
setSessionAttribute(HttpServletRequest request,
String name,
Object value)
Set the session attribute with the given name to the given value.
|
static void |
setWebAppRootSystemProperty(ServletContext servletContext)
Set a system property to the web application root directory.
|
public static final String INCLUDE_REQUEST_URI_ATTRIBUTE
If included via a RequestDispatcher, the current resource will see the originating request. Its own URI and paths are exposed as request attributes.
public static final String INCLUDE_CONTEXT_PATH_ATTRIBUTE
public static final String INCLUDE_SERVLET_PATH_ATTRIBUTE
public static final String INCLUDE_PATH_INFO_ATTRIBUTE
public static final String INCLUDE_QUERY_STRING_ATTRIBUTE
public static final String FORWARD_REQUEST_URI_ATTRIBUTE
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.
public static final String FORWARD_CONTEXT_PATH_ATTRIBUTE
public static final String FORWARD_SERVLET_PATH_ATTRIBUTE
public static final String FORWARD_PATH_INFO_ATTRIBUTE
public static final String FORWARD_QUERY_STRING_ATTRIBUTE
public static final String ERROR_STATUS_CODE_ATTRIBUTE
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.
public static final String ERROR_EXCEPTION_TYPE_ATTRIBUTE
public static final String ERROR_MESSAGE_ATTRIBUTE
public static final String ERROR_EXCEPTION_ATTRIBUTE
public static final String ERROR_REQUEST_URI_ATTRIBUTE
public static final String ERROR_SERVLET_NAME_ATTRIBUTE
public static final String CONTENT_TYPE_CHARSET_PREFIX
public static final String DEFAULT_CHARACTER_ENCODING
request.getCharacterEncoding
returns null
, according to the Servlet spec.public static final String TEMP_DIR_CONTEXT_ATTRIBUTE
java.io.File
.public static final String HTML_ESCAPE_CONTEXT_PARAM
web.xml
): "defaultHtmlEscape".public static final String WEB_APP_ROOT_KEY_PARAM
web.xml
): "webAppRootKey".public static final String DEFAULT_WEB_APP_ROOT_KEY
public static final String[] SUBMIT_IMAGE_SUFFIXES
public static final String SESSION_MUTEX_ATTRIBUTE
public static void setWebAppRootSystemProperty(ServletContext servletContext) throws IllegalStateException
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.
servletContext
- the servlet context of the web applicationIllegalStateException
- if the system property is already set,
or if the WAR file is not expandedWEB_APP_ROOT_KEY_PARAM
,
DEFAULT_WEB_APP_ROOT_KEY
,
WebAppRootListener
,
Log4jWebConfigurer
public static void removeWebAppRootSystemProperty(ServletContext servletContext)
servletContext
- the servlet context of the web applicationsetWebAppRootSystemProperty(javax.servlet.ServletContext)
public static boolean isDefaultHtmlEscape(ServletContext servletContext)
web.xml
(if any). Falls back to false
in case of no explicit default given.servletContext
- the servlet context of the web applicationpublic static Boolean getDefaultHtmlEscape(ServletContext servletContext)
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.
servletContext
- the servlet context of the web applicationpublic static File getTempDir(ServletContext servletContext)
servletContext
- the servlet context of the web applicationpublic static String getRealPath(ServletContext servletContext, String path) throws FileNotFoundException
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).
servletContext
- the servlet context of the web applicationpath
- the path within the web applicationFileNotFoundException
- if the path cannot be resolved to a resourceServletContext.getRealPath(java.lang.String)
public static String getSessionId(HttpServletRequest request)
request
- current HTTP requestnull
if nonepublic static Object getSessionAttribute(HttpServletRequest request, String name)
request
- current HTTP requestname
- the name of the session attributenull
if not foundpublic static Object getRequiredSessionAttribute(HttpServletRequest request, String name) throws IllegalStateException
request
- current HTTP requestname
- the name of the session attributenull
if not foundIllegalStateException
- if the session attribute could not be foundpublic static void setSessionAttribute(HttpServletRequest request, String name, Object value)
request
- current HTTP requestname
- the name of the session attributevalue
- the value of the session attributepublic static Object getOrCreateSessionAttribute(HttpSession session, String name, Class<?> clazz) throws IllegalArgumentException
session
- current HTTP sessionname
- the name of the session attributeclazz
- the class to instantiate for a new attributeIllegalArgumentException
- if the session attribute could not be instantiatedpublic static Object getSessionMutex(HttpSession 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.
session
- the HttpSession to find a mutex fornull
)SESSION_MUTEX_ATTRIBUTE
,
HttpSessionMutexListener
public static <T> T getNativeRequest(ServletRequest request, Class<T> requiredType)
request
- the servlet request to introspectrequiredType
- the desired type of request objectnull
if none
of that type is availablepublic static <T> T getNativeResponse(ServletResponse response, Class<T> requiredType)
response
- the servlet response to introspectrequiredType
- the desired type of response objectnull
if none
of that type is availablepublic static boolean isIncludeRequest(ServletRequest request)
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.
request
- current servlet requestpublic static void exposeForwardRequestAttributes(HttpServletRequest request)
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.
request
- current servlet requestpublic static void exposeErrorRequestAttributes(HttpServletRequest request, Throwable ex, String servletName)
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.
request
- current servlet requestex
- the exception encounteredservletName
- the name of the offending servletpublic static void clearErrorRequestAttributes(HttpServletRequest request)
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
.request
- current servlet requestpublic static void exposeRequestAttributes(ServletRequest request, Map<String,?> attributes)
request
- current HTTP requestattributes
- the attributes Mappublic static Cookie getCookie(HttpServletRequest request, String name)
request
- current servlet requestname
- cookie namenull
if none is foundpublic static boolean hasSubmitParameter(ServletRequest request, String name)
request
- current HTTP requestname
- name of the parameterSUBMIT_IMAGE_SUFFIXES
public static String findParameterValue(ServletRequest request, String name)
See findParameterValue(java.util.Map, String)
for a description of the lookup algorithm.
request
- current HTTP requestname
- the logical name of the request parameternull
if the parameter does not exist in given requestpublic static String findParameterValue(Map<String,?> parameters, String name)
This method will try to obtain a parameter value using the following algorithm:
parameters
- the available parameter mapname
- the logical name of the request parameternull
if the parameter does not exist in given requestpublic static Map<String,Object> getParametersStartingWith(ServletRequest request, String prefix)
For example, with a prefix of "spring_", "spring_param1" and "spring_param2" result in a Map with "param1" and "param2" as keys.
request
- HTTP request in which to look for parametersprefix
- the beginning of parameter names
(if this is null or the empty string, all parameters will match)ServletRequest.getParameterNames()
,
ServletRequest.getParameterValues(java.lang.String)
,
ServletRequest.getParameterMap()
public static int getTargetPage(ServletRequest request, String paramPrefix, int currentPage)
request
- current servlet requestparamPrefix
- the parameter prefix to check for
(e.g. "_target" for parameters like "_target1" or "_target2")currentPage
- the current page, to be returned as fallback
if no target page specifiedpublic static String extractFilenameFromUrlPath(String urlPath)
urlPath
- the request URL path (e.g. "/index.html")public static String extractFullFilenameFromUrlPath(String urlPath)
urlPath
- the request URL path (e.g. "/products/index.html")public static MultiValueMap<String,String> parseMatrixVariables(String matrixVariables)
"q1=a;q1=b;q2=a,b,c"
. The resulting map would contain
keys "q1"
and "q2"
with values ["a","b"]
and
["a","b","c"]
respectively.matrixVariables
- the unparsed matrix variables stringnull