getWriter()和getOutputStream()不能同时调用

HTTP Status 500 ? Internal Server Error

Type Exception Report

Message getWriter() has already been called for this response

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

java.lang.IllegalStateException: getWriter() has already been called for this response
	org.apache.catalina.connector.Response.getOutputStream(Response.java:590)
	org.apache.catalina.connector.ResponseFacade.getOutputStream(ResponseFacade.java:194)
	com.itheima.content.ErrorServlet.doGet(ErrorServlet.java:34)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/8.5.16

HTTP Status 500 ? Internal Server Error

原文：http://www.cnblogs.com/denggelin/p/7226155.html