spring mvc - I am getting an exception: java.lang.IllegalStateException: getOutputStream() has already been called for this response -

i want write code download file persisted in system

here code:

in controller class have following mapping

@requestmapping(value = "/processfile", method = requestmethod.post)     public @responsebody modelandview downloadfileprocess(             @requestparam("file") file originalfile,             @requestparam("action") string action, httpservletresponse response) {          modelandview model = new modelandview();         model.setviewname("error");         system.out.println("");         system.out.println("action: "+action);         model.addobject("message", "action:" + action);         try {             utility.downloadfile(originalfile, response);             message = "the file downloaded successfully";          } catch (ioexception e) {             e.printstacktrace();             message = "the process failed due following reason: "                     + e.getmessage();         } catch (exception e) {             e.printstacktrace();             message = "the process failed due following reason: "                     + e.getmessage();         }         model.setviewname("success");         model.addobject("message", message);         return model;     } 

the method in utility class below:

public void downloadfile(file originalfile, httpservletresponse response)             throws filenotfoundexception, ioexception {          response.setheader("content-disposition", "attachment; filename="                 + originalfile.getname());         ioutils.copy(                 new fileinputstream(new file(string.valueof(originalfile))),                 response.getoutputstream());         response.flushbuffer();      } 

as want download file, have use response.getoutputstream().

but getting following exception:

 java.lang.illegalstateexception: cannot call sendredirect() after response has been committed     @ org.apache.catalina.connector.responsefacade.sendredirect(responsefacade.java:482)     @ org.springframework.web.servlet.view.redirectview.sendredirect(redirectview.java:548)     @ org.springframework.web.servlet.view.redirectview.rendermergedoutputmodel(redirectview.java:279)     @ org.springframework.web.servlet.view.abstractview.render(abstractview.java:267)     @ org.springframework.web.servlet.dispatcherservlet.render(dispatcherservlet.java:1221)     @ org.springframework.web.servlet.dispatcherservlet.processdispatchresult(dispatcherservlet.java:1005)     @ org.springframework.web.servlet.dispatcherservlet.dodispatch(dispatcherservlet.java:952)     @ org.springframework.web.servlet.dispatcherservlet.doservice(dispatcherservlet.java:870)     @ org.springframework.web.servlet.frameworkservlet.processrequest(frameworkservlet.java:961)     @ org.springframework.web.servlet.frameworkservlet.dopost(frameworkservlet.java:863)     @ javax.servlet.http.httpservlet.service(httpservlet.java:646)     @ org.springframework.web.servlet.frameworkservlet.service(frameworkservlet.java:837)     @ javax.servlet.http.httpservlet.service(httpservlet.java:727)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:303)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.springframework.web.filter.hiddenhttpmethodfilter.dofilterinternal(hiddenhttpmethodfilter.java:77)     @ org.springframework.web.filter.onceperrequestfilter.dofilter(onceperrequestfilter.java:107)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:241)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.apache.catalina.core.standardwrappervalve.invoke(standardwrappervalve.java:220)     @ org.apache.catalina.core.standardcontextvalve.invoke(standardcontextvalve.java:122)     @ org.apache.catalina.authenticator.authenticatorbase.invoke(authenticatorbase.java:503)     @ org.apache.catalina.core.standardhostvalve.invoke(standardhostvalve.java:170)     @ org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:103)     @ org.apache.catalina.core.standardenginevalve.invoke(standardenginevalve.java:116)     @ org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:421)     @ org.apache.coyote.http11.abstracthttp11processor.process(abstracthttp11processor.java:1070)     @ org.apache.coyote.abstractprotocol$abstractconnectionhandler.process(abstractprotocol.java:611)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.dorun(nioendpoint.java:1736)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.run(nioendpoint.java:1695)     @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142)     @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617)     @ org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run(taskthread.java:61)     @ java.lang.thread.run(thread.java:745)  2015-05-31 12:42:07.547 error 15009 --- [nio-8080-exec-4] o.a.c.c.c.[.[.[/].[dispatcherservlet]    : servlet.service() servlet dispatcherservlet threw exception  java.lang.illegalstateexception: getoutputstream() has been called response     @ org.apache.catalina.connector.response.getwriter(response.java:678)     @ org.apache.catalina.connector.responsefacade.getwriter(responsefacade.java:213)     @ javax.servlet.servletresponsewrapper.getwriter(servletresponsewrapper.java:104)     @ org.springframework.boot.autoconfigure.web.errormvcautoconfiguration$spelview.render(errormvcautoconfiguration.java:187)     @ org.springframework.web.servlet.dispatcherservlet.render(dispatcherservlet.java:1221)     @ org.springframework.web.servlet.dispatcherservlet.processdispatchresult(dispatcherservlet.java:1005)     @ org.springframework.web.servlet.dispatcherservlet.dodispatch(dispatcherservlet.java:952)     @ org.springframework.web.servlet.dispatcherservlet.doservice(dispatcherservlet.java:870)     @ org.springframework.web.servlet.frameworkservlet.processrequest(frameworkservlet.java:961)     @ org.springframework.web.servlet.frameworkservlet.dopost(frameworkservlet.java:863)     @ javax.servlet.http.httpservlet.service(httpservlet.java:646)     @ org.springframework.web.servlet.frameworkservlet.service(frameworkservlet.java:837)     @ javax.servlet.http.httpservlet.service(httpservlet.java:727)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:303)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.springframework.web.filter.onceperrequestfilter.dofilter(onceperrequestfilter.java:101)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:241)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.apache.catalina.core.applicationdispatcher.invoke(applicationdispatcher.java:748)     @ org.apache.catalina.core.applicationdispatcher.doinclude(applicationdispatcher.java:604)     @ org.apache.catalina.core.applicationdispatcher.include(applicationdispatcher.java:543)     @ org.apache.catalina.core.standardhostvalve.custom(standardhostvalve.java:467)     @ org.apache.catalina.core.standardhostvalve.status(standardhostvalve.java:342)     @ org.apache.catalina.core.standardhostvalve.throwable(standardhostvalve.java:434)     @ org.apache.catalina.core.standardhostvalve.invoke(standardhostvalve.java:205)     @ org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:103)     @ org.apache.catalina.core.standardenginevalve.invoke(standardenginevalve.java:116)     @ org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:421)     @ org.apache.coyote.http11.abstracthttp11processor.process(abstracthttp11processor.java:1070)     @ org.apache.coyote.abstractprotocol$abstractconnectionhandler.process(abstractprotocol.java:611)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.dorun(nioendpoint.java:1736)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.run(nioendpoint.java:1695)     @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142)     @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617)     @ org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run(taskthread.java:61)     @ java.lang.thread.run(thread.java:745)  2015-05-31 12:42:07.551 error 15009 --- [nio-8080-exec-4] o.a.c.c.c.[tomcat].[localhost]           : exception processing errorpage[errorcode=0, location=/error]  org.springframework.web.util.nestedservletexception: request processing failed; nested exception java.lang.illegalstateexception: getoutputstream() has been called response     @ org.springframework.web.servlet.frameworkservlet.processrequest(frameworkservlet.java:973)     @ org.springframework.web.servlet.frameworkservlet.dopost(frameworkservlet.java:863)     @ javax.servlet.http.httpservlet.service(httpservlet.java:646)     @ org.springframework.web.servlet.frameworkservlet.service(frameworkservlet.java:837)     @ javax.servlet.http.httpservlet.service(httpservlet.java:727)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:303)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.springframework.web.filter.onceperrequestfilter.dofilter(onceperrequestfilter.java:101)     @ org.apache.catalina.core.applicationfilterchain.internaldofilter(applicationfilterchain.java:241)     @ org.apache.catalina.core.applicationfilterchain.dofilter(applicationfilterchain.java:208)     @ org.apache.catalina.core.applicationdispatcher.invoke(applicationdispatcher.java:748)     @ org.apache.catalina.core.applicationdispatcher.doinclude(applicationdispatcher.java:604)     @ org.apache.catalina.core.applicationdispatcher.include(applicationdispatcher.java:543)     @ org.apache.catalina.core.standardhostvalve.custom(standardhostvalve.java:467)     @ org.apache.catalina.core.standardhostvalve.status(standardhostvalve.java:342)     @ org.apache.catalina.core.standardhostvalve.throwable(standardhostvalve.java:434)     @ org.apache.catalina.core.standardhostvalve.invoke(standardhostvalve.java:205)     @ org.apache.catalina.valves.errorreportvalve.invoke(errorreportvalve.java:103)     @ org.apache.catalina.core.standardenginevalve.invoke(standardenginevalve.java:116)     @ org.apache.catalina.connector.coyoteadapter.service(coyoteadapter.java:421)     @ org.apache.coyote.http11.abstracthttp11processor.process(abstracthttp11processor.java:1070)     @ org.apache.coyote.abstractprotocol$abstractconnectionhandler.process(abstractprotocol.java:611)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.dorun(nioendpoint.java:1736)     @ org.apache.tomcat.util.net.nioendpoint$socketprocessor.run(nioendpoint.java:1695)     @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142)     @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617)     @ org.apache.tomcat.util.threads.taskthread$wrappingrunnable.run(taskthread.java:61)     @ java.lang.thread.run(thread.java:745) caused by: java.lang.illegalstateexception: getoutputstream() has been called response     @ org.apache.catalina.connector.response.getwriter(response.java:678)     @ org.apache.catalina.connector.responsefacade.getwriter(responsefacade.java:213)     @ javax.servlet.servletresponsewrapper.getwriter(servletresponsewrapper.java:104)     @ org.springframework.boot.autoconfigure.web.errormvcautoconfiguration$spelview.render(errormvcautoconfiguration.java:187)     @ org.springframework.web.servlet.dispatcherservlet.render(dispatcherservlet.java:1221)     @ org.springframework.web.servlet.dispatcherservlet.processdispatchresult(dispatcherservlet.java:1005)     @ org.springframework.web.servlet.dispatcherservlet.dodispatch(dispatcherservlet.java:952)     @ org.springframework.web.servlet.dispatcherservlet.doservice(dispatcherservlet.java:870)     @ org.springframework.web.servlet.frameworkservlet.processrequest(frameworkservlet.java:961)     ... 27 common frames omitted 

1. httpservletresponse.getoutputstream()

   • used write binary data client.
   • data written client not encoded.
   • once flush() called, data flushed client.
   • illegalstateexception thrown if getwriter() method has been called on response object.

2. httpservletresponse.getwriter()

   • returns printwriter object can used write character text (non-binary) data client.
   • data sent client encoded either using default encoding scheme or user provided.
   • once flush() called, data flushed client.
   • illegalstateexception thrown if getoutputstream() method has been called response object

one key usage difference between 2 getoutputstream() sending binary data client , getwriter() sending encoded text data.

bottom line: either of above 2 methods should used flush data client, , not both, , developer has make sure handled, specially when doing things in non-servlet class.