Spring3.0.2 使用 Annotation 与 @Transactional 冲突问题解决方案

项目中使用Spring最新的全Annotation方式，从Controller, Service, 到 DAO全部使用Annotation方式进行开发。

在使用@Transactional 事务处理时，遇到了问题:

配置如下：

web.xml

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext/db-config.xml</param-value>
</context-param>

<servlet>
    <servlet-name>SillServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext/mvc-config.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>SillServlet</servlet-name>
    <url-pattern>/app/*</url-pattern>
</servlet-mapping>

mvc-config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans>
    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
    <!-- 对项目中的所有文件进行扫描-->
    <context:component-scan base-package="com.*.*.*.*" />
</beans>

 db-config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans>
    <context:property-placeholder location="/WEB-INF/applicationContext/jdbc.properties" />
    <bean id="sqlMapClientTemplate" class="org.springframework.orm.ibatis.SqlMapClientTemplate">
        <property name="sqlMapClient" ref="sqlMapClient" />
    </bean>

    <bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
        <property name="configLocation" value="/WEB-INF/sqlmap/sqlMapping.xml" />
        <property name="dataSource" ref="dataSource" />
    </bean>

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
        <property name="driverClass" value="${jdbc.driverClassName}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    <tx:annotation-driven />
</beans>

Controller类如下：

@Controller
@RequestMapping("/check")
public class CheckController {
    private Logger         logger = LoggerFactory.getLogger(WelcomeController.class);
    @Autowired
    private PrepareService prepareService;

    @RequestMapping(method = RequestMethod.GET)
    public void check(HttpServletRequest request, HttpServletResponse response) throws Exception {
        String id = ServletRequestUtils.getStringParameter(request, "id");

        Map<String, Object> mapdata = new HashMap<String, Object>();
        mapdata.put("userId", userId);
        mapdata.put("script", script);
        prepareService.addUserInputScript(mapdata);
    }

    @RequestMapping("/show")
    public ModelAndView show(HttpServletRequest request, Map<String, Object> model) throws Exception {
        String number = ServletRequestUtils.getStringParameter(request, "id");
        model.put("account", number);
        return new ModelAndView("welcome", model);
    }
}

ServiceHandler：

@Service
public class PrepareServiceHandler implements PrepareService {

    @Autowired
    private ScriptDAO          scriptDAO;

    @Autowired
    private ConditionDAO       conditionDAO;

    /**
     * 需要事务支持的Function
     */
    @Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor = Exception.class)
    public void addUserInputScript(...) throws Exception {
        scriptDAO.addScript(...);
        conditionDAO.addCondition(...);
    }
}

DAO:(只提供一个例子)

@Repository
public class ScriptDAOImpl implements ScriptDAO {

    private @Resource(name = "sqlMapClientTemplate") SqlMapClientTemplate sqlMapClientTemplate;

    private static final String SQL_MAPPING_TABLE     = "SCRIPTS.SQL_MAPPING_TABLE";

    @Override
    public Integer addScript(ScriptDO scriptDO) {
        return (Integer) sqlMapClientTemplate.insert(SQL_MAPPING_TABLE, scriptDO);
    }
}

OK，如果上述Bean,并不是通过Annotation定义，而是通过<bean id=".." class=".."> 声明式写明在配置文件 Transactional 是好用的。

但是通过Annotation来定义，就不是那么回事了。

原因就是

<context:component-scan base-package="com.*.*.*.*" />

出现在spring mvc的配置文件中时，web 容器在配置的路径中扫描包含@Controller, @Service, @Repository或@Components等的类并且也会包含扫描@Transaction，但是此时@Transaction并未完成初始化，导致事务未被注册。

怎么解决呢，搜了2天也没有搜到比较好的解决办法：有的是通过context:component-scan 中的 context:exclude-filter, 把带@Transaction的类排除，之后再声明式的写到配置文件中，很不爽，感觉就是一种兑付的态度。

如果是使用两个扫描器怎么样，将原来的配置分成两部分，将扫描其他目录的context:component放入context-param 的 contextConfigLocation文件，该文件为org.springframework.web.context.ContextLoaderListener的加载文件。

controller还是由servlet来装载。

代码如下：

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext/db-config.xml</param-value>
    </context-param>

    <servlet>
        <servlet-name>SillServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/applicationContext/mvc-config.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>SillServlet</servlet-name>
        <url-pattern>/app/*</url-pattern>
    </servlet-mapping>

</web-app>

mvc-config:

<?xml version="1.0" encoding="UTF-8"?>
<beans>
    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

    <!-- 只针对action包中的controller进行扫描 -->
    <context:component-scan base-package="com.*.*.*.*.action" />
</beans>

db-config:

<?xml version="1.0" encoding="UTF-8"?>
<beans>
    <context:property-placeholder location="/WEB-INF/applicationContext/jdbc.properties" />

    <bean id="sqlMapClientTemplate" class="org.springframework.orm.ibatis.SqlMapClientTemplate">
        <property name="sqlMapClient" ref="sqlMapClient" />
    </bean>

    <bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
        <property name="configLocation" value="/WEB-INF/sqlmap/sqlMapping.xml" />
        <property name="dataSource" ref="dataSource" />
    </bean>

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
        destroy-method="close">
        <property name="driverClass" value="${jdbc.driverClassName}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <tx:annotation-driven   />

    <!--Spring 扫描除controller以外的Bean -->
    <context:component-scan base-package="com.*.*.*.*">
        <context:exclude-filter type="regex" expression=".*Controller$" />
    </context:component-scan>
</beans>

再RunTest,OK~!

重点回顾：

1.spring初始化时优先component-scan bean,注入Web Controller 的Service直接拿了上下文中的@Service("someService"),这个时候@Transactional 还没有被处理.所以Web Controller 的Service是SomeServiceImpl而不是AOP的$ProxyNO.

2.必须分开以不同的方式进行加载，Controller 由 Servlet-init进行扫描，Service与DAO由context扫描，这样做就需要区分路径与controller的文件名。

以上观点，瑾我个人观点，如果有更简捷实用的方法希望大家赐教～