struts2文件下载

1.  struts2文件下载

1)        Action类

package com.morris.ajax.action;   import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import java.io.UnsupportedEncodingException;   import javax.servlet.http.HttpServletRequest;   import org.apache.struts2.ServletActionContext;   import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport;   public class FileDownAction extends ActionSupport {            private static final long serialVersionUID = 1L;            private String fileName;            private InputStream inputStream;            public String getFileName() {                    return fileName;          }            public void setFileName(String fileName)                             throws UnsupportedEncodingException {                    // 解决请求文件名中文乱码                    fileName = new String(fileName.getBytes("iso-8859-1"), "utf-8");                    this.fileName = fileName;          }     //对应配置文件中 <param name="inputName">inputStream</param>的getter方法          public InputStream getInputStream() throws FileNotFoundException,                             UnsupportedEncodingException {                      String realPath = ServletActionContext.getRequest().getRealPath("/");                      System.out.println(realPath + "file\\" + fileName);                      InputStream inputStream = new FileInputStream(realPath + "file\\"                                      + fileName);                    // 防止下载时候中文乱码                    fileName = new String(fileName.getBytes("GBK"), "iso-8859-1");                      return inputStream;          }            public String down() {                    return SUCCESS;          } }

2)        struts2配置文件的配置

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"> <struts>    <package name="default" extends="struts-default" namespace="/">       <action name="fileDown" class="com.morris.ajax.action.FileDownAction"         method="down">         <result name="success" type="stream">            <param name="contentType">text/plain</param>            <param name="contentDisposition">attachment;filename=${fileName}</param>            <param name="inputName">inputStream</param>            <param name="bufferSize">1024</param>         </result>       </action>    </package> </struts>

错误解决

1)        在struts2中使用result里type="stream"的结果类型时，可以实现文件的下载管理，使用时也是比较顺畅，但是当在“下载提示窗口”中点击“取消按钮”时，总是报出“java.lang.IllegalStateException”异常，异常内容如下：

严重: Servlet.service() for servlet default threw exception java.lang.IllegalStateException          at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:407)          at org.apache.struts2.dispatcher.Dispatcher.sendError(Dispatcher.java:770)          at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:505)          at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)          at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)          at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)          at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)          at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)          at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)          at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)          at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)          at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)          at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)          at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)          at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)          at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)          at java.lang.Thread.run(Thread.java:619)

2)        异常分析

stream对应的类是org.apache.struts2.dispatcher.StreamResult，该类的处理过程如下：

i.             配置其中result标签下的各个参数

ii.             从服务器中获取输入流，并同时与客户端建立输出流（服务器与客户端链接通过Socket进行连接）

iii.             当点击“保存”或“打开”时，开始传输数据。如果点击“取消”，关闭所有的流。

这里要注意的是，但是实际发现Socket并没有断开！并且流也没有关闭！这一点非常重要！

所以在JSP容器通过Response获取输出流之前，前面的流并没有关闭，所以会造成该异常的报出。

3)        异常解决

i.             将jar包struts2-sunspoter-stream-1.0.jar引入工程中

ii.             在原有的struts.xml的基础上进行相应的配置

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"> <struts>          <package name="default" extends="struts-default" namespace="/">                    <result-types>                             <result-type name="streamx"                                      class="com.sunspoter.lib.web.struts2.dispatcher.StreamResultX" />                    </result-types>                    <action name="fileDown" class="com.morris.ajax.action.FileDownAction"                             method="down">                             <result name="success" type="streamx">                                      <param name="contentType">text/plain</param>                                      <param name="contentDisposition">attachment;filename=${fileName}</param>                                      <param name="inputName">inputStream</param>                                      <param name="bufferSize">1024</param>                             </result>                    </action>          </package> </struts>

在这种方式下，只需添加一个result-type，将原有的result中type改为“streamx”，其他一律不变，在这种情况下，点击“取消”的同时也关闭了流，不会再报出该异常。

 之后的执行“取消”后的结果如下

警告:StreamResultX Warn : socket write error