预告: 重点请看最后面。
做excel导出时遇到的问题,很多时候会遇到此错误,异常如下:
- java.lang.IllegalStateException: getWriter() has already been called for this response
- at org.apache.catalina.connector.Response.getOutputStream(Response.java:628)
- at org.apache.catalina.connector.ResponseFacade.getOutputStream(ResponseFacade.java:196)
- at com.wrt.action.order.EndOrderAction.exportInfo(EndOrderAction.java:143)
- at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
- at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
- at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
- at java.lang.reflect.Method.invoke(Method.java:606)
- at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:446)
- at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:285)
- at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
- at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
- at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
- at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176)
- at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
- at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
- at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
- at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
- at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
- at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
背景如下:
使用Struts2框架,点击某个按钮实现列表excel导出
2.大致代码如下
- public void exportInfo(){
- try {
- //web对象
- HSSFWorkbook wb = new HSSFWorkbook();
- //创建表头等
- HSSFSheet sheet = wb.createSheet("test1");
- //创建行
- HSSFRow row = sheet.createRow(0);
- //创建列
- HSSFCell cell = row.createCell(0);
- //**************省略excel创建部分..
- HttpServletResponse response = ServletActionContext.getResponse();
- OutputStream output = getRepsonse().getOutputStream();
- response.reset();
- response.setHeader("Content-disposition", "attachment; filename=details.xls");
- response.setContentType("application/msexcel");
- wb.write(output);
- output.close();
- System.out.println("成功创建excel文件");
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
最终解决方案,将response.reset(); 放到OutputStream output = getRepsonse().getOutputStream();前面,
- HttpServletResponse response = ServletActionContext.getResponse();
- response.reset();
- OutputStream output = getRepsonse().getOutputStream();
- response.setHeader("Content-disposition", "attachment; filename=details.xls");
- response.setContentType("application/msexcel");
运行效果如下成功。
.
原因,避免可能出现未关闭的getWriter(),使用了response.reset();进行刷新,而此时却在未刷新的情况下进行了OutputStream output = getRepsonse().getOutputStream();操作..... 简之:就是位置放错了 .
会出现如下异常的三种可能:
1.通过response.reset(); 刷新可能存在一些未关闭的getWriter(). 来源:http://blog.csdn.net/wonder4/article/details/8476603
2.struts2请求方法中返回了success此类会返回数据或者界面的,举例如下:
public String saveSubmitOrder(){
return "success";
}
改成
public String saveSubmitOrder(){
return null;
}
或者void。
3.存在多个getWriter且未关闭状态,或者getWriter与OutputStream同时出现。
总之,一个请求过来只会有一个返回结果,如果存在两个或以上则会出现此异常.
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