Write operations are not allowed in read-only mode

 此异常是由于Spring提供的Open Session In View而引起的。 
     
     开启OpenSessionInViewFilter这个过滤器的时候FlushMode就已经被默认设置为了MANUAL，如果FlushMode是MANUAL或NEVEL,在操作过程中 hibernate会将事务设置为readonly，所以在增加、删除或修改操作过程中会出现该错误  
     <filter>
        <filter-name>hibernateFilterfilter-name>
        <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilterfilter-class>
           <init-param>
                <param-name>flushModeparam-name>
                <param-value>AUTOparam-value>
            init-param>
        <init-param>
            <param-name>singleSessionparam-name>
            <param-value>trueparam-value>
        init-param>
    filter>
    <filter-mapping>
        <filter-name>hibernateFilterfilter-name>
        <url-pattern>/*url-pattern>
    filter-mapping>