json如何与spring结合

Question

使用json来实现用户注册的用户名验证
必须通过操作数据库来执行
在SSH框架中使用Action调DAO来实现
这样结合json怎么用下面是我目前的配置文件struts.xml
====================================
  <package name="json" extends="json-default"> 
   <action name="User" class="com.online.action.UserAction">
   <result type="json"></result>
  </action>
applicationCotext.xml
====================================
<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="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-2.0.xsd"> <!--首先建数据库sample，建表users，开启mysql服务-->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
   <property name="driverClassName"><value>com.mysql.jdbc.Driver</value></property>
   <property name="url"><value>jdbc:mysql://localhost:3306/online</value></property>
   <property name="username"><value>root</value></property>
   <property name="password"><value>123</value></property>
</bean> <bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
 <property name="dataSource">
            <ref bean="dataSource" />
        </property>
 <property name="hibernateProperties">
           <props>
              <prop key="hibernate.dialect">
                  org.hibernate.dialect.MySQLDialect
              </prop>
           </props>
      </property>
      <property name="mappingResources">
            <list>
            <value>com/online/dao/Login.hbm.xml</value>
               </list>
        </property>
</bean> <bean id="loginDAO" class="com.online.dao.LoginDAO"> 
<property name="sessionFactory"> 
<ref local="sessionFactory" /> 
</property> 
</bean> 

<bean id="accountService" class="com.online.service.AccountService">
<property name="loginDAO">
           <ref bean="loginDAO" /> 
       </property>
</bean>

<bean name="/Account"
        class="com.online.action.AccountAction">
       <!-- RegisterAction中住的service的名称 -->
       <property name="accountService">
           <ref bean="accountService" />
       </property>
     </bean>
    
     <bean name="/User"
        class="com.online.action.UserAction">
       <!-- RegisterAction中住的service的名称 -->
       <property name="accountService">
           <ref bean="accountService" />
       </property>
     </bean>
</beans>++++++++++++++++++++++++++++++++++++++++++++++++++++启动tomcat时报错-----〉org.springframework.beans.factory.BeanCreationException: Error creating bean with name '/User' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyException: Invalid property 'accountService' of bean class [com.online.action.UserAction]: Bean property 'accountService' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?
Caused by: org.springframework.beans.NotWritablePropertyException: Invalid property 'accountService' of bean class [com.online.action.UserAction]: Bean property 'accountService' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?
at org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:793)
at org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:645)
我的配置有问题。需要大虾们的帮忙