(Struts2文件下载）Can not find a java.io.InputStream with the name [inputStream] in the invocation stack

转载自  kaisep

最终编辑  yeyeok

2010-1-22 9:45:03 org.apache.struts2.dispatcher.StreamResult doExecute 严重: 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. 2010-1-22 9:45:03 org.apache.catalina.core.StandardWrapperValve invoke 严重: Servlet.service() for servlet default threw exception 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) ==========================解决办法=========================== 这个错误报的真有点误导人呀,我还一直以为我struts.xml中<param name="inputName">inputStream</param>和action中的方法名getInputStream()不一致的问题,大家如果也碰到此类问题,直接打印 InputStream in=ServletActionContext.getServletContext().getResourceAsStream(realPath); System.out.println(in); 如果打印为NULL的话,恭喜您,问题得以解决,问题的原因是这个流的realPath路径错误,像我的, //  String realPath=ServletActionContext.getServletContext().getRealPath("/uploadImages")+ "/"+name; 路径错误    String realPath="/uploadImages/"+name;正确的 ===================================================== 没明白的,请看下面的详细说来 怪呀,我的配置应该没错呀 页面上: <a href="fileDownload.action?fileName=<s:property value ="imageName" />">下载此图片</a> struts.xml中 ---------------------------------------------------------- <!-- 文件下载，支持中文附件名 -->    <action name="fileDownload"     class="com.test.action.filedown.FileDownloadAction">     <result name="success" type="stream">      <!-- 动态文件下载的，事先并不知道未来的文件类型，那么我们可以把它的值设置成为：application/octet-stream;charset=ISO8859-1 ，注意一定要加入charset，否则某些时候会导致下载的文件出错； -->      <param name="contentType">      application/octet-stream;charset=ISO8859-1      </param>      <param name="contentDisposition">       attachment;filename="${downloadFileName}"      </param>      <!-- 使用经过转码的文件名作为下载文件名，downloadFileName属性       对应action类中的方法 getDownloadFileName() 其中特殊的代码就是${downloadFileName}，它的效果相当于运行的时候将action对象的属性的取值动态的填充在${}中间的部分，我们可以认为它等价于＋action. getDownloadFileName()。 -->      <param name="inputName">inputStream</param>      <param name="bufferSize">4096</param>     </result>    </action> ---------------------------------------------------------- action中 ---------------------------------------------------------- private String fileName;// 初始的通过param指定的文件名属性 set get /** 文件名 转换编码 防止中文乱码*/ public String getDownloadFileName() {    String fileName=ServletActionContext.getRequest().getParameter("fileName");    String downFileName = fileName;    try {     downFileName = new String(downFileName.getBytes(), "ISO8859-1");    } catch (Exception e) {     e.printStackTrace();    }    return downFileName; } //下载的流 public InputStream getInputStream() {    String name=this.getDownloadFileName(); //  String realPath=ServletActionContext.getServletContext().getRealPath("/uploadImages")+ "/"+name; 路径错误    String realPath="/uploadImages/"+name;    InputStream in=ServletActionContext.getServletContext().getResourceAsStream(realPath);    if(null==in){     System.out.println("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.检查action中文件下载路径是否正确.");       }    return ServletActionContext.getServletContext().getResourceAsStream(realPath); } @Override public String execute() throws Exception {    return SUCCESS; }