转 httpServletResponse reset flushBuffer

httpServletResponse reset flushBuffer

reset():Clears any data that exists in the buffer as well as the status code and headers. If the response has been committed, this method throws an IllegalStateException.

该方法必须在response commited之前进行,该方法将buffer中的所有数据清空.

flushBuffer:Forces any content in the buffer to be written to the client. A call to this method automatically commits the response, meaning the status code and headers will be written.

该方法被调用后,改response 将被提交.

程序:
resp.reset();
        System.out.println("response if commited: "+resp.isCommitted());
        resp.flushBuffer();
        System.out.println("response if commited: "+resp.isCommitted());

结果:
response if commited: false
response if commited: true



resp.flushBuffer();
        System.out.println("response if commited: "+resp.isCommitted());
        resp.reset();
        System.out.println("response if commited: "+resp.isCommitted());

结果:
response if commited: true
Jan 7, 2010 10:54:25 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet setCookie threw exception
java.lang.IllegalStateException
    at org.apache.catalina.connector.ResponseFacade.reset(ResponseFacade.java:310)
    at com.myapp1.cookie.WriteCookie.doGet(WriteCookie.java:58)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    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(Unknown Source)