org.springframework.web.servlet

Class HttpServletBean

java.lang.Object

HttpServlet

org.springframework.web.servlet.HttpServletBean

All Implemented Interfaces:

Aware, EnvironmentAware, EnvironmentCapable

Direct Known Subclasses:

FrameworkServlet, ResourceServlet

public abstract class HttpServletBean
extends HttpServlet
implements EnvironmentCapable, EnvironmentAware

Simple extension of javax.servlet.http.HttpServlet which treats its config parameters (init-param entries within the servlet tag in web.xml) as bean properties.

A handy superclass for any type of servlet. Type conversion of config parameters is automatic, with the corresponding setter method getting invoked with the converted value. It is also possible for subclasses to specify required properties. Parameters without matching bean property setter will simply be ignored.

This servlet leaves request handling to subclasses, inheriting the default behavior of HttpServlet (doGet, doPost, etc).

This generic servlet base class has no dependency on the Spring ApplicationContext concept. Simple servlets usually don't load their own context but rather access service beans from the Spring root application context, accessible via the filter's ServletContext (see WebApplicationContextUtils).

The FrameworkServlet class is a more specific servlet base class which loads its own application context. FrameworkServlet serves as direct base class of Spring's full-fledged DispatcherServlet.

Author:

Rod Johnson, Juergen Hoeller

See Also:

addRequiredProperty(java.lang.String), initServletBean(), #doGet, #doPost

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	HttpServletBean.ServletConfigPropertyValues PropertyValues implementation created from ServletConfig init parameters.

Field Summary

Fields

Modifier and Type	Field and Description
private ConfigurableEnvironment	environment
protected Log	logger Logger available to subclasses
private java.util.Set<java.lang.String>	requiredProperties Set of required properties (Strings) that must be supplied as config parameters to this servlet.

Constructor Summary

Constructors

Constructor and Description
HttpServletBean()

Method Summary

Modifier and Type	Method and Description
protected void	addRequiredProperty(java.lang.String property) Subclasses can invoke this method to specify that this property (which must match a JavaBean property they expose) is mandatory, and must be supplied as a config parameter.
protected ConfigurableEnvironment	createEnvironment() Create and return a new StandardServletEnvironment.
ConfigurableEnvironment	getEnvironment() Return the Environment associated with this component.
ServletContext	getServletContext() Overridden method that simply returns null when no ServletConfig set yet.
java.lang.String	getServletName() Overridden method that simply returns null when no ServletConfig set yet.
void	init() Map config parameters onto bean properties of this servlet, and invoke subclass initialization.
protected void	initBeanWrapper(BeanWrapper bw) Initialize the BeanWrapper for this HttpServletBean, possibly with custom editors.
protected void	initServletBean() Subclasses may override this to perform custom initialization.
void	setEnvironment(Environment environment) Set the Environment that this object runs in.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected final Log logger

Logger available to subclasses

requiredProperties

private final java.util.Set<java.lang.String> requiredProperties

Set of required properties (Strings) that must be supplied as config parameters to this servlet.

environment

private ConfigurableEnvironment environment

Constructor Detail

HttpServletBean

public HttpServletBean()

Method Detail

addRequiredProperty

protected final void addRequiredProperty(java.lang.String property)

Subclasses can invoke this method to specify that this property (which must match a JavaBean property they expose) is mandatory, and must be supplied as a config parameter. This should be called from the constructor of a subclass.

This method is only relevant in case of traditional initialization driven by a ServletConfig instance.

Parameters:

property - name of the required property

init

public final void init()
                throws ServletException

Map config parameters onto bean properties of this servlet, and invoke subclass initialization.

Throws:

ServletException - if bean properties are invalid (or required properties are missing), or if subclass initialization fails.

initBeanWrapper

protected void initBeanWrapper(BeanWrapper bw)
                        throws BeansException

Initialize the BeanWrapper for this HttpServletBean, possibly with custom editors.

This default implementation is empty.

Parameters:

bw - the BeanWrapper to initialize

Throws:

BeansException - if thrown by BeanWrapper methods

See Also:

PropertyEditorRegistry.registerCustomEditor(java.lang.Class<?>, java.beans.PropertyEditor)

getServletName

public final java.lang.String getServletName()

Overridden method that simply returns null when no ServletConfig set yet.

See Also:

#getServletConfig()

getServletContext

public final ServletContext getServletContext()

Overridden method that simply returns null when no ServletConfig set yet.

See Also:

#getServletConfig()

initServletBean

protected void initServletBean()
                        throws ServletException

Subclasses may override this to perform custom initialization. All bean properties of this servlet will have been set before this method is invoked.

This default implementation is empty.

Throws:

ServletException - if subclass initialization fails

setEnvironment

public void setEnvironment(Environment environment)

Set the Environment that this object runs in.

Specified by:

setEnvironment in interface EnvironmentAware

Throws:

java.lang.IllegalArgumentException - if environment is not assignable to ConfigurableEnvironment.

getEnvironment

public ConfigurableEnvironment getEnvironment()

Return the Environment associated with this component.

If null, a new environment will be initialized via createEnvironment().

Specified by:

getEnvironment in interface EnvironmentCapable

createEnvironment

protected ConfigurableEnvironment createEnvironment()

Create and return a new StandardServletEnvironment. Subclasses may override in order to configure the environment or specialize the environment type returned.