Spring Framework

org.springframework.web.servlet.view
Class UrlBasedViewResolver

java.lang.Object
  extended by org.springframework.context.support.ApplicationObjectSupport
      extended by org.springframework.web.context.support.WebApplicationObjectSupport
          extended by org.springframework.web.servlet.view.AbstractCachingViewResolver
              extended by org.springframework.web.servlet.view.UrlBasedViewResolver
All Implemented Interfaces:
Aware, ApplicationContextAware, Ordered, ServletContextAware, ViewResolver
Direct Known Subclasses:
AbstractTemplateViewResolver, InternalResourceViewResolver, JasperReportsViewResolver, TilesViewResolver, XsltViewResolver

public class UrlBasedViewResolver
extends AbstractCachingViewResolver
implements Ordered

Simple implementation of the ViewResolver interface, allowing for direct resolution of symbolic view names to URLs, without explicit mapping definition. This is useful if your symbolic names match the names of your view resources in a straightforward manner (i.e. the symbolic name is the unique part of the resource's filename), without the need for a dedicated mapping to be defined for each view.

Supports AbstractUrlBasedView subclasses like InternalResourceView, VelocityView and FreeMarkerView. The view class for all views generated by this resolver can be specified via the "viewClass" property.

View names can either be resource URLs themselves, or get augmented by a specified prefix and/or suffix. Exporting an attribute that holds the RequestContext to all views is explicitly supported.

Example: prefix="/WEB-INF/jsp/", suffix=".jsp", viewname="test" -> "/WEB-INF/jsp/test.jsp"

As a special feature, redirect URLs can be specified via the "redirect:" prefix. E.g.: "redirect:myAction.do" will trigger a redirect to the given URL, rather than resolution as standard view name. This is typically used for redirecting to a controller URL after finishing a form workflow.

Furthermore, forward URLs can be specified via the "forward:" prefix. E.g.: "forward:myAction.do" will trigger a forward to the given URL, rather than resolution as standard view name. This is typically used for controller URLs; it is not supposed to be used for JSP URLs - use logical view names there.

Note: This class does not support localized resolution, i.e. resolving a symbolic view name to different resources depending on the current locale.

Note: When chaining ViewResolvers, a UrlBasedViewResolver will check whether the specified resource actually exists. However, with InternalResourceView, it is not generally possible to determine the existence of the target resource upfront. In such a scenario, a UrlBasedViewResolver will always return View for any given view name; as a consequence, it should be configured as the last ViewResolver in the chain.

Since:
13.12.2003
Author:
Juergen Hoeller, Rob Harrop
See Also:
setViewClass(java.lang.Class), setPrefix(java.lang.String), setSuffix(java.lang.String), setRequestContextAttribute(java.lang.String), REDIRECT_URL_PREFIX, AbstractUrlBasedView, InternalResourceView, VelocityView, FreeMarkerView

Field Summary
static java.lang.String FORWARD_URL_PREFIX
          Prefix for special view names that specify a forward URL (usually to a controller after a form has been submitted and processed).
static java.lang.String REDIRECT_URL_PREFIX
          Prefix for special view names that specify a redirect URL (usually to a controller after a form has been submitted and processed).
 
Fields inherited from class org.springframework.context.support.ApplicationObjectSupport
logger
 
Fields inherited from interface org.springframework.core.Ordered
HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE
 
Constructor Summary
UrlBasedViewResolver()
           
 
Method Summary
protected  AbstractUrlBasedView buildView(java.lang.String viewName)
          Creates a new View instance of the specified view class and configures it.
protected  boolean canHandle(java.lang.String viewName, java.util.Locale locale)
          Indicates whether or not this ViewResolver can handle the supplied view name.
protected  View createView(java.lang.String viewName, java.util.Locale locale)
          Overridden to implement check for "redirect:" prefix.
 java.util.Map<java.lang.String,java.lang.Object> getAttributesMap()
          Allow Map access to the static attributes for views returned by this resolver, with the option to add or override specific entries.
protected  java.lang.Object getCacheKey(java.lang.String viewName, java.util.Locale locale)
          This implementation returns just the view name, as this ViewResolver doesn't support localized resolution.
protected  java.lang.String getContentType()
          Return the content type for all views, if any.
 int getOrder()
          Return the order in which this ViewResolver is evaluated.
protected  java.lang.String getPrefix()
          Return the prefix that gets prepended to view names when building a URL.
protected  java.lang.String getRequestContextAttribute()
          Return the name of the RequestContext attribute for all views, if any.
protected  java.lang.String getSuffix()
          Return the suffix that gets appended to view names when building a URL.
protected  java.lang.Class getViewClass()
          Return the view class to be used to create views.
protected  java.lang.String[] getViewNames()
          Return the view names (or name patterns) that can be handled by this ViewResolver.
protected  void initApplicationContext()
          Subclasses can override this for custom initialization behavior.
protected  boolean isRedirectContextRelative()
          Return whether to interpret a given redirect URL that starts with a slash ("/") as relative to the current ServletContext, i.e.
protected  boolean isRedirectHttp10Compatible()
          Return whether redirects should stay compatible with HTTP 1.0 clients.
protected  View loadView(java.lang.String viewName, java.util.Locale locale)
          Delegates to buildView for creating a new instance of the specified view class, and applies the following Spring lifecycle methods (as supported by the generic Spring bean factory): ApplicationContextAware's setApplicationContext InitializingBean's afterPropertiesSet
protected  java.lang.Class requiredViewClass()
          Return the required type of view for this resolver.
 void setAttributes(java.util.Properties props)
          Set static attributes from a java.util.Properties object, for all views returned by this resolver.
 void setAttributesMap(java.util.Map<java.lang.String,?> attributes)
          Set static attributes from a Map, for all views returned by this resolver.
 void setContentType(java.lang.String contentType)
          Set the content type for all views.
 void setExposePathVariables(java.lang.Boolean exposePathVariables)
          Whether views resolved by this resolver should add path variables the model or not.
 void setOrder(int order)
          Set the order in which this ViewResolver is evaluated.
 void setPrefix(java.lang.String prefix)
          Set the prefix that gets prepended to view names when building a URL.
 void setRedirectContextRelative(boolean redirectContextRelative)
          Set whether to interpret a given redirect URL that starts with a slash ("/") as relative to the current ServletContext, i.e.
 void setRedirectHttp10Compatible(boolean redirectHttp10Compatible)
          Set whether redirects should stay compatible with HTTP 1.0 clients.
 void setRequestContextAttribute(java.lang.String requestContextAttribute)
          Set the name of the RequestContext attribute for all views.
 void setSuffix(java.lang.String suffix)
          Set the suffix that gets appended to view names when building a URL.
 void setViewClass(java.lang.Class viewClass)
          Set the view class that should be used to create views.
 void setViewNames(java.lang.String[] viewNames)
          Set the view names (or name patterns) that can be handled by this ViewResolver.
 
Methods inherited from class org.springframework.web.servlet.view.AbstractCachingViewResolver
clearCache, isCache, isCacheUnresolved, removeFromCache, resolveViewName, setCache, setCacheUnresolved
 
Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport
getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, initServletContext, isContextRequired, setServletContext
 
Methods inherited from class org.springframework.context.support.ApplicationObjectSupport
getApplicationContext, getMessageSourceAccessor, requiredContextClass, setApplicationContext
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

REDIRECT_URL_PREFIX

public static final java.lang.String REDIRECT_URL_PREFIX
Prefix for special view names that specify a redirect URL (usually to a controller after a form has been submitted and processed). Such view names will not be resolved in the configured default way but rather be treated as special shortcut.

See Also:
Constant Field Values

FORWARD_URL_PREFIX

public static final java.lang.String FORWARD_URL_PREFIX
Prefix for special view names that specify a forward URL (usually to a controller after a form has been submitted and processed). Such view names will not be resolved in the configured default way but rather be treated as special shortcut.

See Also:
Constant Field Values
Constructor Detail

UrlBasedViewResolver

public UrlBasedViewResolver()
Method Detail

setViewClass

public void setViewClass(java.lang.Class viewClass)
Set the view class that should be used to create views.

Parameters:
viewClass - class that is assignable to the required view class (by default, AbstractUrlBasedView)
See Also:
AbstractUrlBasedView

getViewClass

protected java.lang.Class getViewClass()
Return the view class to be used to create views.


requiredViewClass

protected java.lang.Class requiredViewClass()
Return the required type of view for this resolver. This implementation returns AbstractUrlBasedView.

See Also:
AbstractUrlBasedView

setPrefix

public void setPrefix(java.lang.String prefix)
Set the prefix that gets prepended to view names when building a URL.


getPrefix

protected java.lang.String getPrefix()
Return the prefix that gets prepended to view names when building a URL.


setSuffix

public void setSuffix(java.lang.String suffix)
Set the suffix that gets appended to view names when building a URL.


getSuffix

protected java.lang.String getSuffix()
Return the suffix that gets appended to view names when building a URL.


setContentType

public void setContentType(java.lang.String contentType)
Set the content type for all views.

May be ignored by view classes if the view itself is assumed to set the content type, e.g. in case of JSPs.


getContentType

protected java.lang.String getContentType()
Return the content type for all views, if any.


setRedirectContextRelative

public void setRedirectContextRelative(boolean redirectContextRelative)
Set whether to interpret a given redirect URL that starts with a slash ("/") as relative to the current ServletContext, i.e. as relative to the web application root.

Default is "true": A redirect URL that starts with a slash will be interpreted as relative to the web application root, i.e. the context path will be prepended to the URL.

Redirect URLs can be specified via the "redirect:" prefix. E.g.: "redirect:myAction.do"

See Also:
RedirectView.setContextRelative(boolean), REDIRECT_URL_PREFIX

isRedirectContextRelative

protected boolean isRedirectContextRelative()
Return whether to interpret a given redirect URL that starts with a slash ("/") as relative to the current ServletContext, i.e. as relative to the web application root.


setRedirectHttp10Compatible

public void setRedirectHttp10Compatible(boolean redirectHttp10Compatible)
Set whether redirects should stay compatible with HTTP 1.0 clients.

In the default implementation, this will enforce HTTP status code 302 in any case, i.e. delegate to HttpServletResponse.sendRedirect. Turning this off will send HTTP status code 303, which is the correct code for HTTP 1.1 clients, but not understood by HTTP 1.0 clients.

Many HTTP 1.1 clients treat 302 just like 303, not making any difference. However, some clients depend on 303 when redirecting after a POST request; turn this flag off in such a scenario.

Redirect URLs can be specified via the "redirect:" prefix. E.g.: "redirect:myAction.do"

See Also:
RedirectView.setHttp10Compatible(boolean), REDIRECT_URL_PREFIX

isRedirectHttp10Compatible

protected boolean isRedirectHttp10Compatible()
Return whether redirects should stay compatible with HTTP 1.0 clients.


setRequestContextAttribute

public void setRequestContextAttribute(java.lang.String requestContextAttribute)
Set the name of the RequestContext attribute for all views.

Parameters:
requestContextAttribute - name of the RequestContext attribute
See Also:
AbstractView.setRequestContextAttribute(java.lang.String)

getRequestContextAttribute

protected java.lang.String getRequestContextAttribute()
Return the name of the RequestContext attribute for all views, if any.


setAttributes

public void setAttributes(java.util.Properties props)
Set static attributes from a java.util.Properties object, for all views returned by this resolver.

This is the most convenient way to set static attributes. Note that static attributes can be overridden by dynamic attributes, if a value with the same name is included in the model.

Can be populated with a String "value" (parsed via PropertiesEditor) or a "props" element in XML bean definitions.

See Also:
PropertiesEditor, AbstractView.setAttributes(java.util.Properties)

setAttributesMap

public void setAttributesMap(java.util.Map<java.lang.String,?> attributes)
Set static attributes from a Map, for all views returned by this resolver. This allows to set any kind of attribute values, for example bean references.

Can be populated with a "map" or "props" element in XML bean definitions.

Parameters:
attributes - Map with name Strings as keys and attribute objects as values
See Also:
AbstractView.setAttributesMap(java.util.Map)

getAttributesMap

public java.util.Map<java.lang.String,java.lang.Object> getAttributesMap()
Allow Map access to the static attributes for views returned by this resolver, with the option to add or override specific entries.

Useful for specifying entries directly, for example via "attributesMap[myKey]". This is particularly useful for adding or overriding entries in child view definitions.


setViewNames

public void setViewNames(java.lang.String[] viewNames)
Set the view names (or name patterns) that can be handled by this ViewResolver. View names can contain simple wildcards such that 'my*', '*Report' and '*Repo*' will all match the view name 'myReport'.

See Also:
canHandle(java.lang.String, java.util.Locale)

getViewNames

protected java.lang.String[] getViewNames()
Return the view names (or name patterns) that can be handled by this ViewResolver.


setOrder

public void setOrder(int order)
Set the order in which this ViewResolver is evaluated.


getOrder

public int getOrder()
Return the order in which this ViewResolver is evaluated.

Specified by:
getOrder in interface Ordered
Returns:
the order value

setExposePathVariables

public void setExposePathVariables(java.lang.Boolean exposePathVariables)
Whether views resolved by this resolver should add path variables the model or not. The default setting is to allow each View decide (see AbstractView.setExposePathVariables(boolean). However, you can use this property to override that.

Parameters:
exposePathVariables -
  • true - all Views resolved by this resolver will expose path variables
  • false - no Views resolved by this resolver will expose path variables
  • null - individual Views can decide for themselves (this is used by the default)

initApplicationContext

protected void initApplicationContext()
Description copied from class: ApplicationObjectSupport
Subclasses can override this for custom initialization behavior.

The default implementation is empty. Called by ApplicationObjectSupport.initApplicationContext(org.springframework.context.ApplicationContext).

Overrides:
initApplicationContext in class ApplicationObjectSupport
See Also:
ApplicationObjectSupport.setApplicationContext(org.springframework.context.ApplicationContext)

getCacheKey

protected java.lang.Object getCacheKey(java.lang.String viewName,
                                       java.util.Locale locale)
This implementation returns just the view name, as this ViewResolver doesn't support localized resolution.

Overrides:
getCacheKey in class AbstractCachingViewResolver

createView

protected View createView(java.lang.String viewName,
                          java.util.Locale locale)
                   throws java.lang.Exception
Overridden to implement check for "redirect:" prefix.

Not possible in loadView, since overridden loadView versions in subclasses might rely on the superclass always creating instances of the required view class.

Overrides:
createView in class AbstractCachingViewResolver
Parameters:
viewName - the name of the view to retrieve
locale - the Locale to retrieve the view for
Returns:
the View instance, or null if not found (optional, to allow for ViewResolver chaining)
Throws:
java.lang.Exception - if the view couldn't be resolved
See Also:
loadView(java.lang.String, java.util.Locale), requiredViewClass()

canHandle

protected boolean canHandle(java.lang.String viewName,
                            java.util.Locale locale)
Indicates whether or not this ViewResolver can handle the supplied view name. If not, createView(String, java.util.Locale) will return null. The default implementation checks against the configured view names.

Parameters:
viewName - the name of the view to retrieve
locale - the Locale to retrieve the view for
Returns:
whether this resolver applies to the specified view
See Also:
PatternMatchUtils.simpleMatch(String, String)

loadView

protected View loadView(java.lang.String viewName,
                        java.util.Locale locale)
                 throws java.lang.Exception
Delegates to buildView for creating a new instance of the specified view class, and applies the following Spring lifecycle methods (as supported by the generic Spring bean factory):

Specified by:
loadView in class AbstractCachingViewResolver
Parameters:
viewName - the name of the view to retrieve
locale - the Locale to retrieve the view for
Returns:
the View instance
Throws:
java.lang.Exception - if the view couldn't be resolved
See Also:
buildView(String), ApplicationContextAware.setApplicationContext(org.springframework.context.ApplicationContext), InitializingBean.afterPropertiesSet()

buildView

protected AbstractUrlBasedView buildView(java.lang.String viewName)
                                  throws java.lang.Exception
Creates a new View instance of the specified view class and configures it. Does not perform any lookup for pre-defined View instances.

Spring lifecycle methods as defined by the bean container do not have to be called here; those will be applied by the loadView method after this method returns.

Subclasses will typically call super.buildView(viewName) first, before setting further properties themselves. loadView will then apply Spring lifecycle methods at the end of this process.

Parameters:
viewName - the name of the view to build
Returns:
the View instance
Throws:
java.lang.Exception - if the view couldn't be resolved
See Also:
loadView(String, java.util.Locale)

Spring Framework