响应已提交

Question

我有一个取消按钮，用来刷新数值。现在，我已经将它们转换为刷新或重新加载页面，并移动到只读页面。所以改变了取消按钮来调用这样的函数，

function chkArea(){

        var url='<c:out value="${model.contextPath}"/>/abcHandler.do?operation=view;
        document.forms[0].action=url;
        document.forms[0].submit();
    }

现在，当我提交cancel时，我在UI中得到以下消息，

java.lang.IllegalStateException: Response has already been committed    at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.EvermindHttpServletResponse.resetBuffer(EvermindHttpServletResponse.java:1892)    at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ServletRequestDispatcher.unprivileged_forward(ServletRequestDispatcher.java:249)  at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ServletRequestDispatcher.access$100(ServletRequestDispatcher.java:51) at com.evermind[Oracle Containers for J2EE 10g (10.1.3.4.0) ].server.http.ServletRequestDispatcher$2.oc4jRun(ServletRequestDispatcher.java:193) at oracle.oc4j.security.OC4JSecurity.doPrivileged(OC4JSecurity.java:284)........

控制台显示以下错误：

javax.servlet.ServletException: The "url" attribute illegally evaluated to "null" or "" in <import>
    at com.evermind.server.http.EvermindPageContext.handlePageThrowable(EvermindPageContext.java:899)
    at com.evermind.server.http.EvermindPageContext.handlePageException(EvermindPageContext.java:816)

我在JS或JSP中看不到任何错误。似乎出了什么问题？有什么建议吗？

Answer 1

当您在jsp的输出流上写入内容，然后再次对其执行某些操作时，就会出现此错误。这会导致IllegalStateException。当响应已经提交时，您不应该执行任何操作。所谓提交，我的意思是将响应发送回客户端。一个常见的场景是

 OutputStream stream = response.getOutPutStream();
  stream.write("something here");
  stream.flush();
 RequestDispatcher rd = request.getRequestDispatcher("someFile.jsp");
   rd.forward(request, response); // You can't do this because stream is already written