如何在spring4中配置“CommonsMultipartResolver”，无需xml上传文件

Question

我使用的xml配置spring4工作得很好。像这样：

<bean id="multipartResolver"
    class="org.springframework.web.multipart.commons.CommonsMultipartResolver"
    p:defaultEncoding="utf-8" >
    <!-- one of the properties available; the maximum file size in bytes -->  
    <!-- <property name="maxUploadSize" value="40000000" /> -->  
</bean>

当我在没有xml的情况下配置spring4时。像这样：

@Configuration
@ComponentScan({ "common.user", "service" })
@EnableWebMvc
public class SpringMVCConfig {

@Bean
public ViewResolver createInternalResourceViewResolver() {
    InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
    viewResolver.setViewClass(JstlView.class);
    viewResolver.setContentType("text/html");
    viewResolver.setPrefix("/view/");
    //viewResolver.setSuffix(".jsp");
    return viewResolver;
}

@Bean
public DefaultServletHttpRequestHandler createDefaultServletHttpRequestHandler() {
    return new DefaultServletHttpRequestHandler();
}


@Bean
public CommonsMultipartResolver createMultipartResolver() {
    CommonsMultipartResolver resolver=new CommonsMultipartResolver();
    resolver.setDefaultEncoding("utf-8");
    return resolver;
}

}

它引发异常：

 九月 30, 2014 6:01:08 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [dispatcher] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: Current request is not of type [org.springframework.web.multipart.MultipartHttpServletRequest]: org.apache.catalina.connector.RequestFacade@5ebfad8d] with root cause
java.lang.IllegalStateException: Current request is not of type [org.springframework.web.multipart.MultipartHttpServletRequest]: org.apache.catalina.connector.RequestFacade@5ebfad8d
    at org.springframework.web.servlet.mvc.method.annotation.ServletRequestMethodArgumentResolver.resolveArgument(ServletRequestMethodArgumentResolver.java:97)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:79)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:157)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:124)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at common.servlet.RootFilter.doFilter(RootFilter.java:71)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Answer 1

来自MultipartResolverJavadoc：要定义实现，请在DispatcherServlet的应用程序上下文中创建一个id为“multipartResolver”的bean。

在您的xml配置中，bean的正确id为multipartResolver，但在您当前的java配置中没有。您应该写：

@Bean
public CommonsMultipartResolver multipartResolver() {
    CommonsMultipartResolver resolver=new CommonsMultipartResolver();
    resolver.setDefaultEncoding("utf-8");
    return resolver;
}

或

@Bean(name = "multipartResolver")
public CommonsMultipartResolver createMultipartResolver() {
    CommonsMultipartResolver resolver=new CommonsMultipartResolver();
    resolver.setDefaultEncoding("utf-8");
    return resolver;
}