Shiro多Realm数据交互实现过程

 /**
     * Attempts to authenticate the given token by iterating over the internal collection of
     * {@link Realm}s.  For each realm, first the {@link Realm#supports(org.apache.shiro.authc.AuthenticationToken)}
     * method will be called to determine if the realm supports the {@code authenticationToken} method argument.
     * <p/>
     * If a realm does support
     * the token, its {@link Realm#getAuthenticationInfo(org.apache.shiro.authc.AuthenticationToken)}
     * method will be called.  If the realm returns a non-null account, the token will be
     * considered authenticated for that realm and the account data recorded.  If the realm returns {@code null},
     * the next realm will be consulted.  If no realms support the token or all supporting realms return null,
     * an {@link AuthenticationException} will be thrown to indicate that the user could not be authenticated.
     * <p/>
     * After all realms have been consulted, the information from each realm is aggregated into a single
     * {@link AuthenticationInfo} object and returned.
     *
     * @param authenticationToken the token containing the authentication principal and credentials for the
     *                            user being authenticated.
     * @return account information attributed to the authenticated user.
     * @throws IllegalStateException   if no realms have been configured at the time this method is invoked
     * @throws AuthenticationException if the user could not be authenticated or the user is denied authentication
     *                                 for the given principal and credentials.
     */
    protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
        assertRealmsConfigured();
        Collection<Realm> realms = getRealms();
        if (realms.size() == 1) {
            return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
        } else {
            return doMultiRealmAuthentication(realms, authenticationToken);
        }
    }

多Realm存在的目的:

    将数据保存在多个数据库情况，可以将通过多Realm方式获取两个部分数据。提高数据的安全性。

    关于applicationContext.xml配置两个realm的详情：

 

   第一种方式：

第二种方式：

   realm的bean同第一种，只修改securityManage的配置

 

详解：

    由于ModularRealmAuthenticator认证器中是有getRealms属性的，

public void setRealms(Collection<Realm> realms) {
        this.realms = realms;
    }

    protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
        assertRealmsConfigured();
        Collection<Realm> realms = getRealms();
        if (realms.size() == 1) {
            return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
        } else {
            return doMultiRealmAuthentication(realms, authenticationToken);
        }
    }

一个realm时配置realm:
<bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager">
        <property name="cacheManager" ref="cacheManager"/>
        <property name="realm" ref="jdbcRealm"/>
</bean>
两个realm时配置realm:
<bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager">
        <property name="cacheManager" ref="cacheManager"/>
        <property name="realms">
             <list>
                 <ref bean=""/>
                 <ref bean=" "/>
             </list>
        </property>
</bean>