## org.springframework.web.context.support
Class ServletContextPropertyPlaceholderConfigurer

    java.lang.Object
      org.springframework.core.io.support.PropertiesLoaderSupport
          org.springframework.beans.factory.config.PropertyResourceConfigurer
              org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
                  org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer

All Implemented Interfaces:
  BeanFactoryAware, BeanNameAware, BeanFactoryPostProcessor, Ordered, PriorityOrdered, ServletContextAware

    public class ServletContextPropertyPlaceholderConfigurer

extends PropertyPlaceholderConfigurer
implements ServletContextAware

Subclass of PropertyPlaceholderConfigurer that resolves placeholders as ServletContext init parameters (that is, `web.xml` context-param entries).

Can be combined with "locations" and/or "properties" values in addition to web.xml context-params. Alternatively, can be defined without local properties, to resolve all placeholders as `web.xml` context-params (or JVM system properties).

If a placeholder could not be resolved against the provided local properties within the application, this configurer will fall back to ServletContext parameters. Can also be configured to let ServletContext init parameters override local properties (contextOverride=true).

Optionally supports searching for ServletContext attributes: If turned on, an otherwise unresolvable placeholder will matched against the corresponding ServletContext attribute, using its stringified value if found. This can be used to feed dynamic values into Spring's placeholder resolution.

If not running within a WebApplicationContext (or any other context that is able to satisfy the ServletContextAware callback), this class will behave like the default PropertyPlaceholderConfigurer. This allows for keeping ServletContextPropertyPlaceholderConfigurer definitions in test suites.

Since:
  1.1.4
Author:
  Juergen Hoeller
See Also:
  `PropertiesLoaderSupport.setLocations(org.springframework.core.io.Resource[])`, `PropertiesLoaderSupport.setProperties(java.util.Properties)`, `PropertyPlaceholderConfigurer.setSystemPropertiesModeName(java.lang.String)`, `setContextOverride(boolean)`, `setSearchContextAttributes(boolean)`, `ServletContext.getInitParameter(String)`, `ServletContext.getAttribute(String)`

Field Summary

Fields inherited from class org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
`DEFAULT_PLACEHOLDER_PREFIX, DEFAULT_PLACEHOLDER_SUFFIX, DEFAULT_VALUE_SEPARATOR, SYSTEM_PROPERTIES_MODE_FALLBACK, SYSTEM_PROPERTIES_MODE_NEVER, SYSTEM_PROPERTIES_MODE_OVERRIDE`

Fields inherited from class org.springframework.core.io.support.PropertiesLoaderSupport
`logger, XML_FILE_EXTENSION`

Fields inherited from interface org.springframework.core.Ordered
`HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE`

Constructor Summary
`ServletContextPropertyPlaceholderConfigurer()`

Method Summary
`protected String` `resolvePlaceholder(String placeholder, Properties props)` Resolve the given placeholder using the given properties.
`protected String` `resolvePlaceholder(String placeholder, ServletContext servletContext, boolean searchContextAttributes)` Resolves the given placeholder using the init parameters and optionally also the attributes of the given ServletContext.
`void` `setContextOverride(boolean contextOverride)` Set whether ServletContext init parameters (and optionally also ServletContext attributes) should override local properties within the application.
`void` `setSearchContextAttributes(boolean searchContextAttributes)` Set whether to search for matching a ServletContext attribute before checking a ServletContext init parameter.
`void` `setServletContext(ServletContext servletContext)` Set the ServletContext to resolve placeholders against.

Methods inherited from class org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
`parseStringValue, processProperties, resolvePlaceholder, resolveSystemProperty, setBeanFactory, setBeanName, setIgnoreUnresolvablePlaceholders, setNullValue, setPlaceholderPrefix, setPlaceholderSuffix, setSearchSystemEnvironment, setSystemPropertiesMode, setSystemPropertiesModeName, setValueSeparator`

Methods inherited from class org.springframework.beans.factory.config.PropertyResourceConfigurer
`convertProperties, convertProperty, convertPropertyValue, getOrder, postProcessBeanFactory, setOrder`

Methods inherited from class org.springframework.core.io.support.PropertiesLoaderSupport
`loadProperties, mergeProperties, setFileEncoding, setIgnoreResourceNotFound, setLocalOverride, setLocation, setLocations, setProperties, setPropertiesArray, setPropertiesPersister`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### ServletContextPropertyPlaceholderConfigurer

    public ServletContextPropertyPlaceholderConfigurer()

Method Detail

### setContextOverride

    public void setContextOverride(boolean contextOverride)

  Set whether ServletContext init parameters (and optionally also ServletContext attributes) should override local properties within the application. Default is "false": ServletContext settings serve as fallback.

  Note that system properties will still override ServletContext settings, if the system properties mode is set to "SYSTEM_PROPERTIES_MODE_OVERRIDE".

  See Also:
    `setSearchContextAttributes(boolean)`, `PropertyPlaceholderConfigurer.setSystemPropertiesModeName(java.lang.String)`, `PropertyPlaceholderConfigurer.SYSTEM_PROPERTIES_MODE_OVERRIDE`

### setSearchContextAttributes

    public void setSearchContextAttributes(boolean searchContextAttributes)

  Set whether to search for matching a ServletContext attribute before checking a ServletContext init parameter. Default is "false": only checking init parameters.

  If turned on, the configurer will look for a ServletContext attribute with the same name as the placeholder, and use its stringified value if found. Exposure of such ServletContext attributes can be used to dynamically override init parameters defined in `web.xml`, for example in a custom context listener.

  See Also:
    `ServletContext.getInitParameter(String)`, `ServletContext.getAttribute(String)`

### setServletContext

    public void setServletContext(ServletContext servletContext)

  Set the ServletContext to resolve placeholders against. Will be auto-populated when running in a WebApplicationContext.

  If not set, this configurer will simply not resolve placeholders against the ServletContext: It will effectively behave like a plain PropertyPlaceholderConfigurer in such a scenario.

  Specified by:
    `setServletContext` in interface `ServletContextAware`
  Parameters:
    `servletContext` - ServletContext object to be used by this object
  See Also:
    `InitializingBean.afterPropertiesSet()`, `ApplicationContextAware.setApplicationContext(org.springframework.context.ApplicationContext)`

### resolvePlaceholder

    protected String resolvePlaceholder(String placeholder,
                                        Properties props)

  Description copied from class: `PropertyPlaceholderConfigurer`
  Resolve the given placeholder using the given properties. The default implementation simply checks for a corresponding property key.

  Subclasses can override this for customized placeholder-to-key mappings or custom resolution strategies, possibly just using the given properties as fallback.

  Note that system properties will still be checked before respectively after this method is invoked, according to the system properties mode.

  Overrides:
    `resolvePlaceholder` in class `PropertyPlaceholderConfigurer`
  Parameters:
    `placeholder` - the placeholder to resolve
    `props` - the merged properties of this configurer
  Returns:
    the resolved value, of `null` if none
  See Also:
    `PropertyPlaceholderConfigurer.setSystemPropertiesMode(int)`

### resolvePlaceholder

    protected String resolvePlaceholder(String placeholder,
                                        ServletContext servletContext,
                                        boolean searchContextAttributes)

  Resolves the given placeholder using the init parameters and optionally also the attributes of the given ServletContext.

  Default implementation checks ServletContext attributes before init parameters. Can be overridden to customize this behavior, potentially also applying specific naming patterns for parameters and/or attributes (instead of using the exact placeholder name).

  Parameters:
    `placeholder` - the placeholder to resolve
    `servletContext` - the ServletContext to check
    `searchContextAttributes` - whether to search for a matching ServletContext attribute
  Returns:
    the resolved value, of null if none
  See Also:
    `ServletContext.getInitParameter(String)`, `ServletContext.getAttribute(String)`