public class

PropertyPlaceholderConfigurer

extends PlaceholderConfigurerSupport
java.lang.Object
   ↳ org.springframework.core.io.support.PropertiesLoaderSupport
     ↳ org.springframework.beans.factory.config.PropertyResourceConfigurer
       ↳ org.springframework.beans.factory.config.PlaceholderConfigurerSupport
         ↳ org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
Known Direct Subclasses

Class Overview

PlaceholderConfigurerSupport subclass that resolves ${...} placeholders against local properties and/or system properties and environment variables.

As of Spring 3.1, PropertySourcesPlaceholderConfigurer should be used preferentially over this implementation; it is more flexible through taking advantage of the Environment and PropertySource mechanisms also made available in Spring 3.1.

PropertyPlaceholderConfigurer is still appropriate for use when:

  • the spring-context module is not available (i.e., one is using Spring's BeanFactory API as opposed to ApplicationContext).
  • existing configuration makes use of the "systemPropertiesMode" and/or "systemPropertiesModeName" properties. Users are encouraged to move away from using these settings, and rather configure property source search order through the container's Environment; however, exact preservation of functionality may be maintained by continuing to use PropertyPlaceholderConfigurer.

Prior to Spring 3.1, the <context:property-placeholder/> namespace element registered an instance of PropertyPlaceholderConfigurer. It will still do so if using the spring-context-3.0.xsd definition of the namespace. That is, you can preserve registration of PropertyPlaceholderConfigurer through the namespace, even if using Spring 3.1; simply do not update your xsi:schemaLocation and continue using the 3.0 XSD.

See Also

Summary

Constants
int SYSTEM_PROPERTIES_MODE_FALLBACK Check system properties if not resolvable in the specified properties.
int SYSTEM_PROPERTIES_MODE_NEVER Never check system properties.
int SYSTEM_PROPERTIES_MODE_OVERRIDE Check system properties first, before trying the specified properties.
[Expand]
Inherited Constants
From class org.springframework.beans.factory.config.PlaceholderConfigurerSupport
From class org.springframework.core.io.support.PropertiesLoaderSupport
From interface org.springframework.core.Ordered
[Expand]
Inherited Fields
From class org.springframework.beans.factory.config.PlaceholderConfigurerSupport
From class org.springframework.core.io.support.PropertiesLoaderSupport
Public Constructors
PropertyPlaceholderConfigurer()
Public Methods
void setSearchSystemEnvironment(boolean searchSystemEnvironment)
Set whether to search for a matching system environment variable if no matching system property has been found.
void setSystemPropertiesMode(int systemPropertiesMode)
Set how to check system properties: as fallback, as override, or never.
void setSystemPropertiesModeName(String constantName)
Set the system property mode by the name of the corresponding constant, e.g.
Protected Methods
String parseStringValue(String strVal, Properties props, Set<?> visitedPlaceholders)
This method is deprecated. as of Spring 3.0, in favor of using resolvePlaceholder(String, Properties) with PropertyPlaceholderHelper. Only retained for compatibility with Spring 2.5 extensions.
void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
Visit each bean definition in the given bean factory and attempt to replace ${...} property placeholders with values from the given properties.
String resolvePlaceholder(String placeholder, Properties props)
Resolve the given placeholder using the given properties.
String resolvePlaceholder(String placeholder, Properties props, int systemPropertiesMode)
Resolve the given placeholder using the given properties, performing a system properties check according to the given mode.
String resolveSystemProperty(String key)
Resolve the given key as JVM system property, and optionally also as system environment variable if no matching system property has been found.
[Expand]
Inherited Methods
From class org.springframework.beans.factory.config.PlaceholderConfigurerSupport
From class org.springframework.beans.factory.config.PropertyResourceConfigurer
From class org.springframework.core.io.support.PropertiesLoaderSupport
From class java.lang.Object
From interface org.springframework.beans.factory.BeanFactoryAware
From interface org.springframework.beans.factory.BeanNameAware
From interface org.springframework.beans.factory.config.BeanFactoryPostProcessor
From interface org.springframework.core.Ordered

Constants

public static final int SYSTEM_PROPERTIES_MODE_FALLBACK

Also: SpringBeans

Check system properties if not resolvable in the specified properties. This is the default.

Constant Value: 1 (0x00000001)

public static final int SYSTEM_PROPERTIES_MODE_NEVER

Also: SpringBeans

Never check system properties.

Constant Value: 0 (0x00000000)

public static final int SYSTEM_PROPERTIES_MODE_OVERRIDE

Also: SpringBeans

Check system properties first, before trying the specified properties. This allows system properties to override any other property source.

Constant Value: 2 (0x00000002)

Public Constructors

public PropertyPlaceholderConfigurer ()

Also: SpringBeans

Public Methods

public void setSearchSystemEnvironment (boolean searchSystemEnvironment)

Also: SpringBeans

Set whether to search for a matching system environment variable if no matching system property has been found. Only applied when "systemPropertyMode" is active (i.e. "fallback" or "override"), right after checking JVM system properties.

Default is "true". Switch this setting off to never resolve placeholders against system environment variables. Note that it is generally recommended to pass external values in as JVM system properties: This can easily be achieved in a startup script, even for existing environment variables.

NOTE: Access to environment variables does not work on the Sun VM 1.4, where the corresponding getenv() support was disabled - before it eventually got re-enabled for the Sun VM 1.5. Please upgrade to 1.5 (or higher) if you intend to rely on the environment variable support.

See Also

public void setSystemPropertiesMode (int systemPropertiesMode)

Also: SpringBeans

Set how to check system properties: as fallback, as override, or never. For example, will resolve ${user.dir} to the "user.dir" system property.

The default is "fallback": If not being able to resolve a placeholder with the specified properties, a system property will be tried. "override" will check for a system property first, before trying the specified properties. "never" will not check system properties at all.

See Also

public void setSystemPropertiesModeName (String constantName)

Also: SpringBeans

Set the system property mode by the name of the corresponding constant, e.g. "SYSTEM_PROPERTIES_MODE_OVERRIDE".

Parameters
constantName name of the constant
Throws
IllegalArgumentException if an invalid constant was specified
See Also

Protected Methods

protected String parseStringValue (String strVal, Properties props, Set<?> visitedPlaceholders)

Also: SpringBeans

This method is deprecated.
as of Spring 3.0, in favor of using resolvePlaceholder(String, Properties) with PropertyPlaceholderHelper. Only retained for compatibility with Spring 2.5 extensions.

Parse the given String value for placeholder resolution.

Parameters
strVal the String value to parse
props the Properties to resolve placeholders against
visitedPlaceholders the placeholders that have already been visited during the current resolution attempt (ignored in this version of the code)

protected void processProperties (ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)

Also: SpringBeans

Visit each bean definition in the given bean factory and attempt to replace ${...} property placeholders with values from the given properties.

Parameters
beanFactoryToProcess the BeanFactory used by the application context
props the Properties to apply
Throws
BeansException

protected String resolvePlaceholder (String placeholder, Properties props)

Also: SpringBeans

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.

Parameters
placeholder the placeholder to resolve
props the merged properties of this configurer
Returns
  • the resolved value, of null if none
See Also

protected String resolvePlaceholder (String placeholder, Properties props, int systemPropertiesMode)

Also: SpringBeans

Resolve the given placeholder using the given properties, performing a system properties check according to the given mode.

The default implementation delegates to resolvePlaceholder (placeholder, props) before/after the system properties check.

Subclasses can override this for custom resolution strategies, including customized points for the system properties check.

Parameters
placeholder the placeholder to resolve
props the merged properties of this configurer
systemPropertiesMode the system properties mode, according to the constants in this class
Returns
  • the resolved value, of null if none
See Also

protected String resolveSystemProperty (String key)

Also: SpringBeans

Resolve the given key as JVM system property, and optionally also as system environment variable if no matching system property has been found.

Parameters
key the placeholder to resolve as system property key
Returns
  • the system property value, or null if not found
See Also