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.
See this slides: so it is really a spring EL Expression.
来源：https://stackoverflow.com/questions/7885055/configuring-connection-support-for-spring-social-in-xml