超类没有null构造函数，但未提供任何参数

Question

我在我的应用程序中使用Spring Social：

<spring.framework.version>3.2.0.RELEASE</spring.framework.version>
<hibernate.version>4.1.9.Final</hibernate.version>
<commons-dbcp.version>1.4</commons-dbcp.version>
<org.springframework.social-version>1.1.0.BUILD-SNAPSHOT</org.springframework.social-version>
<org.springframework.social.facebook-version>1.1.0.BUILD-SNAPSHOT</org.springframework.social.facebook-version>
<org.springframework-version>3.2.1.RELEASE</org.springframework-version>
<org.springframework.security.crypto-version>3.1.3.RELEASE</org.springframework.security.crypto-version>

当我申请

private final Facebook facebook;

@Inject
public SearchController(Facebook facebook) {
    this.facebook = facebook;
}

到我的HomeController：

@Controller
public class HomeController {


    private final Facebook facebook;

    @Inject
    public HomeController(Facebook facebook) {
        this.facebook = facebook;
    }

    private static final Logger logger = LoggerFactory.getLogger(HomeController.class);

    /**
     * Simply selects the home view to render by returning its name.
     */
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String home(Model model) {
        return "home";
    }

}

注入的工作方式如预期的一样，我可以从中获取信息facebook。但是，当我将其应用到我的其他Cotrollers时，就像这样

@Controller
@Transactional
@RequestMapping(value = "/search")
public class SearchController {

    private static final Logger logger = LoggerFactory.getLogger(SearchController.class);

    private final Facebook facebook;

    @Inject
    public SearchController(Facebook facebook) {
        this.facebook = facebook;
    }

    @PersistenceContext
    private EntityManager entityManager;

    ...

我收到此错误：

mar 05, 2013 12:46:36 EM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [appServlet] in context with path [/project] threw exception [Request processing failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'searchController' defined in file [C:\Users\Nilsi\Downloads\springsource\vfabric-tc-server-developer-2.7.2.RELEASE\base-instance\wtpwebapps\course_info\WEB-INF\classes\com\courseinfo\project\controller\SearchController.class]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class [class com.courseinfo.project.controller.SearchController]: Common causes of this problem include using a final class or a non-visible class; nested exception is java.lang.IllegalArgumentException: Superclass has no null constructors but no arguments were given] with root cause
java.lang.IllegalArgumentException: Superclass has no null constructors but no arguments were given
    at org.springframework.cglib.proxy.Enhancer.emitConstructors(Enhancer.java:721)
    at org.springframework.cglib.proxy.Enhancer.generateClass(Enhancer.java:499)
    at org.springframework.cglib.transform.TransformingClassGenerator.generateClass(TransformingClassGenerator.java:33)
    at org.springframework.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
    at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:216)
    at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:377)
    at org.springframework.cglib.proxy.Enhancer.create(Enhancer.java:285)
    at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:205)
    at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:111)
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.createProxy(AbstractAutoProxyCreator.java:477)
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.wrapIfNecessary(AbstractAutoProxyCreator.java:362)
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessAfterInitialization(AbstractAutoProxyCreator.java:322)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:412)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1492)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:524)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1117)
    at org.springframework.web.method.HandlerMethod.createWithResolvedBean(HandlerMethod.java:202)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:233)
    at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:55)
    at org.springframework.web.servlet.handler.AbstractHandlerMapping.getHandler(AbstractHandlerMapping.java:297)
    at org.springframework.web.servlet.DispatcherServlet.getHandler(DispatcherServlet.java:1091)
    at org.springframework.web.servlet.DispatcherServlet.getHandler(DispatcherServlet.java:1076)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:896)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:920)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:827)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:801)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

我的猜测是我不能将Facebook注入带有注解@Transactional的Controller吗？我四处搜寻，但找不到任何解决方案。

Answer 1

CGlib有一个重要的限制：目标类必须提供默认的构造函数。

如果使用基于属性的注入而不是基于构造函数的注入，则问题将消失。