Package org.springframework.web.util

Class WebUtils

  • public abstract class WebUtils
extends Object
    Miscellaneous utilities for web applications. Used by various framework classes.
    Author:
    Rod Johnson, Juergen Hoeller, Sebastien Deleuze

    • Field Detail

      • INCLUDE_REQUEST_URI_ATTRIBUTE

        public static final String INCLUDE_REQUEST_URI_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for include request URI.

        If included via a RequestDispatcher, the current resource will see the originating request. Its own request URI is exposed as a request attribute.

        See Also:
        Constant Field Values

      • INCLUDE_CONTEXT_PATH_ATTRIBUTE

        public static final String INCLUDE_CONTEXT_PATH_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for include context path.

        If included via a RequestDispatcher, the current resource will see the originating context path. Its own context path is exposed as a request attribute.

        See Also:
        Constant Field Values

      • INCLUDE_SERVLET_PATH_ATTRIBUTE

        public static final String INCLUDE_SERVLET_PATH_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for include servlet path.

        If included via a RequestDispatcher, the current resource will see the originating servlet path. Its own servlet path is exposed as a request attribute.

        See Also:
        Constant Field Values

      • INCLUDE_PATH_INFO_ATTRIBUTE

        public static final String INCLUDE_PATH_INFO_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for include path info.

        If included via a RequestDispatcher, the current resource will see the originating path info. Its own path info is exposed as a request attribute.

        See Also:
        Constant Field Values

      • INCLUDE_QUERY_STRING_ATTRIBUTE

        public static final String INCLUDE_QUERY_STRING_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for include query string.

        If included via a RequestDispatcher, the current resource will see the originating query string. Its own query string is exposed as a request attribute.

        See Also:
        Constant Field Values

      • FORWARD_REQUEST_URI_ATTRIBUTE

        public static final String FORWARD_REQUEST_URI_ATTRIBUTE
        Standard Servlet 2.4+ spec request attribute for forward request URI.

        If forwarded to via a RequestDispatcher, the current resource will see its own request URI. The originating request URI is exposed as a request attribute.

        See Also:
        Constant Field Values

      • FORWARD_CONTEXT_PATH_ATTRIBUTE

        public static final String FORWARD_CONTEXT_PATH_ATTRIBUTE
        Standard Servlet 2.4+ spec request attribute for forward context path.

        If forwarded to via a RequestDispatcher, the current resource will see its own context path. The originating context path is exposed as a request attribute.

        See Also:
        Constant Field Values

      • FORWARD_SERVLET_PATH_ATTRIBUTE

        public static final String FORWARD_SERVLET_PATH_ATTRIBUTE
        Standard Servlet 2.4+ spec request attribute for forward servlet path.

        If forwarded to via a RequestDispatcher, the current resource will see its own servlet path. The originating servlet path is exposed as a request attribute.

        See Also:
        Constant Field Values

      • FORWARD_PATH_INFO_ATTRIBUTE

        public static final String FORWARD_PATH_INFO_ATTRIBUTE
        Standard Servlet 2.4+ spec request attribute for forward path info.

        If forwarded to via a RequestDispatcher, the current resource will see its own path ingo. The originating path info is exposed as a request attribute.

        See Also:
        Constant Field Values

      • FORWARD_QUERY_STRING_ATTRIBUTE

        public static final String FORWARD_QUERY_STRING_ATTRIBUTE
        Standard Servlet 2.4+ spec request attribute for forward query string.

        If forwarded to via a RequestDispatcher, the current resource will see its own query string. The originating query string is exposed as a request attribute.

        See Also:
        Constant Field Values

      • ERROR_STATUS_CODE_ATTRIBUTE

        public static final String ERROR_STATUS_CODE_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page status code.

        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.

        See Also:
        Constant Field Values

      • ERROR_EXCEPTION_TYPE_ATTRIBUTE

        public static final String ERROR_EXCEPTION_TYPE_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page exception type.

        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.

        See Also:
        Constant Field Values

      • ERROR_MESSAGE_ATTRIBUTE

        public static final String ERROR_MESSAGE_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page message.

        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.

        See Also:
        Constant Field Values

      • ERROR_EXCEPTION_ATTRIBUTE

        public static final String ERROR_EXCEPTION_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page exception.

        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.

        See Also:
        Constant Field Values

      • ERROR_REQUEST_URI_ATTRIBUTE

        public static final String ERROR_REQUEST_URI_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page request URI.

        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.

        See Also:
        Constant Field Values

      • ERROR_SERVLET_NAME_ATTRIBUTE

        public static final String ERROR_SERVLET_NAME_ATTRIBUTE
        Standard Servlet 2.3+ spec request attribute for error page servlet name.

        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.

        See Also:
        Constant Field Values

    • Constructor Detail

    • Method Detail

      • getDefaultHtmlEscape

        @Nullable
public static Boolean getDefaultHtmlEscape​(@Nullable
                                           ServletContext servletContext)
        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.

        Parameters:
        servletContext - the servlet context of the web application
        Returns:
        whether default HTML escaping is enabled for the given application (null = no explicit default)

      • getResponseEncodedHtmlEscape

        @Nullable
public static Boolean getResponseEncodedHtmlEscape​(@Nullable
                                                   ServletContext servletContext)
        Return whether response encoding should be used when HTML escaping characters, thus only escaping XML markup significant characters with UTF-* encodings. This option is enabled for the web application with a ServletContext param, i.e. the value of the "responseEncodedHtmlEscape" 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.

        Parameters:
        servletContext - the servlet context of the web application
        Returns:
        whether response encoding is to be used for HTML escaping (null = no explicit default)
        Since:
        4.1.2

      • getTempDir

        public static File getTempDir​(ServletContext servletContext)
        Return the temporary directory for the current web application, as provided by the servlet container.
        Parameters:
        servletContext - the servlet context of the web application
        Returns:
        the File representing the temporary directory

      • getRealPath

        public static String getRealPath​(ServletContext servletContext,
                                 String path)
                          throws FileNotFoundException
        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).

        Parameters:
        servletContext - the servlet context of the web application
        path - the path within the web application
        Returns:
        the corresponding real path
        Throws:
        FileNotFoundException - if the path cannot be resolved to a resource
        See Also:
        ServletContext.getRealPath(java.lang.String)

      • getSessionAttribute

        @Nullable
public static Object getSessionAttribute​(HttpServletRequest request,
                                         String name)
        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!
        Parameters:
        request - current HTTP request
        name - the name of the session attribute
        Returns:
        the value of the session attribute, or null if not found

      • getRequiredSessionAttribute

        public static Object getRequiredSessionAttribute​(HttpServletRequest request,
                                                 String name)
                                          throws IllegalStateException
        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!
        Parameters:
        request - current HTTP request
        name - the name of the session attribute
        Returns:
        the value of the session attribute, or null if not found
        Throws:
        IllegalStateException - if the session attribute could not be found

      • setSessionAttribute

        public static void setSessionAttribute​(HttpServletRequest request,
                                       String name,
                                       @Nullable
                                       Object value)
        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!
        Parameters:
        request - current HTTP request
        name - the name of the session attribute
        value - the value of the session attribute

      • getSessionMutex

        public 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.

        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.

        Parameters:
        session - the HttpSession to find a mutex for
        Returns:
        the mutex object (never null)
        See Also:
        SESSION_MUTEX_ATTRIBUTE, HttpSessionMutexListener

      • getNativeRequest

        @Nullable
public static <T> T getNativeRequest​(ServletRequest request,
                                     @Nullable
                                     Class<T> requiredType)
        Return an appropriate request object of the specified type, if available, unwrapping the given request as far as necessary.
        Parameters:
        request - the servlet request to introspect
        requiredType - the desired type of request object
        Returns:
        the matching request object, or null if none of that type is available

      • getNativeResponse

        @Nullable
public static <T> T getNativeResponse​(ServletResponse response,
                                      @Nullable
                                      Class<T> requiredType)
        Return an appropriate response object of the specified type, if available, unwrapping the given response as far as necessary.
        Parameters:
        response - the servlet response to introspect
        requiredType - the desired type of response object
        Returns:
        the matching response object, or null if none of that type is available

      • isIncludeRequest

        public 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.

        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.

        Parameters:
        request - current servlet request
        Returns:
        whether the given request is an include request

      • exposeErrorRequestAttributes

        public static void exposeErrorRequestAttributes​(HttpServletRequest request,
                                                Throwable ex,
                                                @Nullable
                                                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.

        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.

        Parameters:
        request - current servlet request
        ex - the exception encountered
        servletName - the name of the offending servlet

      • clearErrorRequestAttributes

        public 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.
        Parameters:
        request - current servlet request

      • getCookie

        @Nullable
public static Cookie getCookie​(HttpServletRequest request,
                               String name)
        Retrieve the first cookie with the given name. Note that multiple cookies can have the same name but different paths or domains.
        Parameters:
        request - current servlet request
        name - cookie name
        Returns:
        the first cookie with the given name, or null if none is found

      • hasSubmitParameter

        public 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").
        Parameters:
        request - current HTTP request
        name - the name of the parameter
        Returns:
        if the parameter was sent
        See Also:
        SUBMIT_IMAGE_SUFFIXES

      • findParameterValue

        @Nullable
public static String findParameterValue​(Map<String,​?> parameters,
                                        String name)
        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.
        Parameters:
        parameters - the available parameter map
        name - the logical name of the request parameter
        Returns:
        the value of the parameter, or null if the parameter does not exist in given request

      • parseMatrixVariables

        public static MultiValueMap<String,​String> parseMatrixVariables​(String matrixVariables)
        Parse the given string with matrix variables. An example string would look like this "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.
        Parameters:
        matrixVariables - the unparsed matrix variables string
        Returns:
        a map with matrix variable names and values (never null)
        Since:
        3.2

      • isValidOrigin

        public static boolean isValidOrigin​(HttpRequest request,
                                    Collection<String> allowedOrigins)
        Check the given request origin against a list of allowed origins. A list containing "*" means that all origins are allowed. An empty list means only same origin is allowed.

        Note: as of 5.1 this method ignores "Forwarded" and "X-Forwarded-*" headers that specify the client-originated address. Consider using the ForwardedHeaderFilter to extract and use, or to discard such headers.

        Returns:
        true if the request origin is valid, false otherwise
        Since:
        4.1.5
        See Also:
        RFC 6454: The Web Origin Concept

      • isSameOrigin

        public static boolean isSameOrigin​(HttpRequest request)
        Check if the request is a same-origin one, based on Origin, Host, Forwarded, X-Forwarded-Proto, X-Forwarded-Host and X-Forwarded-Port headers.

        Note: as of 5.1 this method ignores "Forwarded" and "X-Forwarded-*" headers that specify the client-originated address. Consider using the ForwardedHeaderFilter to extract and use, or to discard such headers.

        Returns:
        true if the request is a same-origin one, false in case of cross-origin request
        Since:
        4.2