struts2下载异常问题

Question

不好意思， 异常是这样的   java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [inputStream] in the invocation stack. Check the <param name="inputName"> tag specified for this action. 
at org.apache.struts2.dispatcher.StreamResult.doExecute(StreamResult.java:189) 
at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:178) 
at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:348) 
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253) 
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221) 
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223) 
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) 
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221) 
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150) 
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48) 
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)

Answer 1

不好意思， 异常是这样的   java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [inputStream] in the invocation stack. Check the <param name="inputName"> tag specified for this action. 
at org.apache.struts2.dispatcher.StreamResult.doExecute(StreamResult.java:189) 
at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:178) 
at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:348) 
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:253) 
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:221) 
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:223) 
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) 
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221) 
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150) 
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48) 
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) 
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224) 

Answer 2

ServletActionContext.getServletContext().getResourceAsStream("/upload/"+filename); 这一部分取得的值是Null。。最好是绝对路径。。

Answer 3

struts 2下载拦截器需要common-io.jar（大概是叫这个名），到www.apache.org下这个包

Answer 4

http://www.javaeye.com/problems/5165这里面有你要的答案