Configuring connection support for spring social i

问题:

I am working spring mvc that integrated spring social. I cannot understand the following configuration that is provided by user guide at

http://static.springsource.org/spring-social/docs/1.0.x/reference/html/connecting.html (4.2.1 Configuring connection support in XML)

<bean id="connectionRepository" factory-method="createConnectionRepository" factory-bean="usersConnectionRepository" scope="request">
<constructor-arg value="#{request.userPrincipal.name}" />

What does it means by "#{request.userPrincipal.name}" or what is the value of it. please help.

回答1:

It looks like a Spring EL - Expression.

Nerveless the reference documentation does not mention request as a special variable in spring el. But this must not mean anything: may I did not have a look at the right places or it is just one more poorly documented feature.

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See this slides: so it is really a spring EL Expression.