Spring中@Component、@Repository、@Service和 @Controller的默认bean名称

若使用过滤器自定义扫描 <context:component-scan base-package="xxx"> 
spring开发手册中这样写： 

当一个组件在某个扫描过程中被自动检测到时，会根据那个扫描器的BeanNameGenerator 策略生成它的bean名称。默认情况下，任何包含 name值的Spring“典型”注解 (@Component、@Repository、 @Service和@Controller) 会把那个名字 提供给相关的bean定义。如果这个注解不包含name值或是其他检测到的组件 (比如被自定义过滤器发现的)，默认bean名称生成器会返回小写开头的非限定(non-qualified)类名。

也就是说被加了注解扫描到spring容器中的bean会默认将小写开头的类名 作为bean的name,供其他地方引用.

例如:以下两个组件在spring中引用的名称分别是'customUserDetailsService '和 'detailService'

@Service
public class CustomUserDetailsService implements UserDetailsService {}


@Service("detailService")
public class CustomUserDetailsService implements UserDetailsService {}

举个实例:

在项目中 遇到这个地方做了bean引用,但是没有发现这个customUserDetailsService在xml中的定义,经查后发现CustomUserDetailsService类上做了@Service注解,所以使用customUserDetailsService可以在xml中引用到它.

<!-- 此文件用于标准登录方式 -->
<beans:beans xmlns="http://www.springframework.org/schema/security"
             xmlns:beans="http://www.springframework.org/schema/beans"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
                                 http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-4.0.xsd">


    <http security="none" pattern="/resources/**"/>
    <http security="none" pattern="/lib/**"/>

    <http access-decision-manager-ref="accessDecisionManager">
        <csrf request-matcher-ref="csrfSecurityRequestMatcher"  />
        <!--<csrf disabled="true"/>-->
        <intercept-url pattern="/login" access="permitAll" />
        <intercept-url pattern="/timeout" access="permitAll" />
        <intercept-url pattern="/login.html" access="permitAll" />
        <intercept-url pattern="/verifiCode" access="permitAll" />
        <intercept-url pattern="/common/**" access="permitAll" />
        <intercept-url pattern="/websocket/**" access="permitAll" />
        <intercept-url pattern="/**" access="hasRole('ROLE_USER')" />
        <access-denied-handler error-page="/access-denied"/>
        <session-management invalid-session-url="/timeout"/>

        <form-login login-page='/login' authentication-success-handler-ref="successHandler"
                    authentication-failure-handler-ref="loginFailureHandler"/>
                    <!--authentication-failure-url="/login?error=true"/>-->
        <!-- 验证码拦截器 -->
        <custom-filter ref="captchaVerifierFilter" before="FORM_LOGIN_FILTER"/>

        <logout logout-url="/logout" success-handler-ref="logoutHandler"/>

        <headers defaults-disabled="true">
            <cache-control/>
        </headers>
    </http>

    <beans:bean id="loginFailureHandler" class="com.hand.hap.security.LoginFailureHandler"/>


    <!-- 认证管理器,确定用户,角色及相应的权限 -->
    <beans:bean id="accessDecisionManager" class="org.springframework.security.access.vote.UnanimousBased">
        <!-- 投票器 -->
        <beans:constructor-arg>
            <beans:list>

                <beans:bean class="com.hand.hap.security.CustomWebExpressionVoter"/>
                <beans:bean class="org.springframework.security.access.vote.RoleVoter"/>
                <beans:bean class="org.springframework.security.access.vote.AuthenticatedVoter"/>
                <beans:bean class="com.hand.hap.security.PermissionVoter"/>
            </beans:list>
        </beans:constructor-arg>
    </beans:bean>

    <!--<beans:import resource="standardSecurity-LDAP.xml"/>-->
    <authentication-manager>
        <!--Ldap验证-->
        <!-- <authentication-provider ref="ldapAuthProvider" />-->
        <!--标准登录验证-->
        <authentication-provider user-service-ref="customUserDetailsService">
            <password-encoder ref="passwordManager"/>
        </authentication-provider>
    </authentication-manager>

    <beans:bean id="captchaVerifierFilter" class="com.hand.hap.security.CaptchaVerifierFilter">
        <beans:property name="captchaField" value="verifiCode"/>
    </beans:bean>

    <beans:bean id="successHandler" class="com.hand.hap.security.CustomAuthenticationSuccessHandler">
       <!-- <beans:property name="defaultTargetUrl" value="/index"/>-->
    </beans:bean>



    <beans:bean id="logoutHandler" class="com.hand.hap.security.CustomLogoutSuccessHandler"></beans:bean>

    <beans:bean id="csrfSecurityRequestMatcher" class="com.hand.hap.security.CsrfSecurityRequestMatcher">
           <beans:property name="excludeUrls">
                <beans:list>
                   <beans:value>/login</beans:value>
                   <beans:value>/websocket/**</beans:value>
              </beans:list>
            </beans:property>
    </beans:bean>

</beans:beans>

这是今天遇到的一个疑惑,在这里做个记录.

总结:

Spring中用@Component、@Repository、@Service和 @Controller等标注的默认Bean名称是小写开头的类名