Tapestry/Spring Integration

系统管理员 2022-07-12 08:36 231阅读 0赞

http://tapestry.apache.org/tapestry5/tapestry-spring/

Provides integration between Tapestry and Spring, allowing beans defined by Spring to be injected into Tapestry IoC services, and into Tapestry components.

## Changes From 5.0 ##

You may now use the @Inject or @InjectService annotations inside Spring beans; these will be resolved to Tapestry services or other objects available via the MasterObjectProvider. Please see the [detailed guide to Injection][] .

The dependency on Spring is no longer scope "provider" and has changed to 2.5.6.

**Spring Beans are no longer exposed as services, unless 5.0 compatibility mode is enabled.**

You no longer create a ContextLoaderListener.

These changes represent an unfortunate backwards compatibility issue. If necessary, you can still use tapestry-spring version 5.0.18 with the rest of Tapestry.

## Spring Version ##

This module is compiled and tested against Spring 2.5.6. It should be resonable to override the dependency to earlier versions of Spring, though the code makes use of some APIs that were added to Spring to support JDK 1.5 annotations.

## Usage ##

The integration is designed to be a very thin layer on top of Spring's normal configuration for a web application.

Detailed instructions are available in the [Spring documentation][] . Please omit the part about creating a ContextLoaderListener: this is now done automatically by Tapestry.

### web.xml changes ###

The short form is that you must make two small changes to your application's web.xml.

First, a special filter is used in replace of the standard TapestryFilter:

<filter>
    
        <filter-name>app</filter-name>
    
        
    
        <filter-class>org.apache.tapestry5.spring.TapestrySpringFilter</filter-class>
    
      </filter>

Secondly, you may add the normal Spring configuration, consisting of an optional <context-param> identifying which Spring bean configuration file(s) to load:

<context-param>
    
      <param-name>contextConfigLocation</param-name>
    
      <param-value>/WEB-INF/daoContext.xml /WEB-INF/applicationContext.xml</param-value>
    
    </context-param>

The <context-param> lists the Spring bean configuration file. It is optional and defaults to just /WEB-INF/applicationContext.xml if omitted.

### Injecting beans ###

Inside your component classes, you may use the [Inject][] annotation. Typically, just the field type is sufficient to identify the Spring bean to inject:

@Inject
    
      private UserDAO userDAO;

Searching for Spring beans is threaded into the [MasterObjectProvider service][detailed guide to Injection] . The Spring context becomes one more place that Tapestry searches when determining the injection for a injected field or method parameter.

## ApplicationContext Service ##

The Spring ApplicationContext is also added as a service.

## ApplicationContextCustomizer ##

A new chain-of-command service, [ApplicationContextCustomizer][] allows the application context, created by Tapestry, to be customized as it is created. You may contribute your own ApplicationContextCustomizer instances as needed.

## 5.0 Compatibility Mode ##

In some circumstances, it is desirable to configure the Spring ApplicationContext externally. The context <config-param> "tapestry.use-external-spring-context" can be configured to "true". Tapestry will then use an existing ApplicationContext, provided by a Spring ContextLoaderListener. You will still be able to inject Spring beans into Tapestry components and services, and the ApplicationContext service will be visible ... but you will not be able to inject Tapestry IoC services into Spring beans.

This option provides compatibility with the tapestry-spring 5.0, including exposing Spring beans as Tapestry IoC services (something that no longer occurs unless compatibility mode is enabled).

## Limitations ##

Non-singleton beans are not handled properly. Tapestry will request the beans from the application context in a manner unsuitable for their lifecycle. For the moment, you should consider the non-singleton beans to be not-injectable. Instead, inject the ApplicationContext service and obtain the non-singleton beans as needed.

[detailed guide to Injection]: http://tapestry.apache.org/tapestry5/tapestry-ioc/injection.html
[Spring documentation]: http://static.springframework.org/spring/docs/2.5.x/reference/beans.html#context-create
[Inject]: http://tapestry.apache.org/tapestry5/apidocs/org/apache/tapestry5/ioc/annotations/Inject.html
[ApplicationContextCustomizer]: http://tapestry.apache.org/tapestry5/apidocs/org/apache/tapestry5/spring/ApplicationContextCustomizer.html