下面的代码抛出IllegalStateException: Cannot forward after response has been committed ：
private void doRequest(HttpServletRequest request) throws IOException, ServletException {
CallableStatement stmt = null;
ResultSet rs = null;
String someString;
try {
this.connectDB();
stmt = this.conn.prepareCall("{call sp_SomeSP1(?)}");
stmt.setLong(1, someFunc());
rs = stmt.executeQuery();
while (rs.next()) {
if (rs.getInt(1)==someOtherFunc()) {
someString = rs.getString(2);
break;
}
}
stmt = conn.prepareCall("{call sp_someSP(?, ?)}");
stmt.setLong(1, someFunc());
stmt.setTimestamp(2, new Timestamp(getFrom().getTime()));
rs = stmt.executeQuery();
if (rs.next()) {
lastUpdated = rs.getTimestamp("LastUpdated");
}
request.setAttribute("lastUpdated", lastUpdated);
LOGGER.debug("Forwarding to view...");
getServletContext().getRequestDispatcher("/SomeJSP.jsp").forward(this.request, this.response);
} catch (NamingException e) {
LOGGER.error("Database connection lookup failed", e);
sendError("Server Error");
} catch (SQLException e) {
LOGGER.error("Query failed", e);
sendError("Server Error");
} catch (IllegalStateException e) {
LOGGER.error("View failed", e);
} finally {
try {
if (rs!=null) rs.close();
} catch (NullPointerException e) {
LOGGER.error("Result set closing failed", e);
} catch (SQLException e) {
LOGGER.error("Result set closing failed", e);
}
try {
if (stmt!=null) stmt.close();
} catch (NullPointerException e) {
LOGGER.error("Statement closing failed", e);
} catch (SQLException e) {
LOGGER.error("Statement closing failed", e);
}
try {
this.closeDB();
} catch (NullPointerException e) {
LOGGER.error("Database connection closing failed", e);
} catch (SQLException e) {
LOGGER.error("Database connection closing failed", e);
}
}
在 JSP 页面中有此代码，因此页面将刷新：
<meta http-equiv="Refresh" content="10">
问题是，错误大多数时候不会发生，只有当我Servlet在多个浏览器或选项卡中访问转发到 JSP 时，但并非总是如此，只有一段时间才会发生错误。
可能是什么问题呢？
堆栈跟踪：
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:339)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:103)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Dec 20, 2012 5:04:58 PM org.apache.jasper.runtime.JspFactoryImpl internalGetPageContext
SEVERE: Exception initializing page context
java.lang.IllegalStateException: Page needs a session and none is available
at org.apache.jasper.runtime.PageContextImpl._initialize(PageContextImpl.java:148)
at org.apache.jasper.runtime.PageContextImpl.initialize(PageContextImpl.java:125)
at org.apache.jasper.runtime.JspFactoryImpl.internalGetPageContext(JspFactoryImpl.java:112)
at org.apache.jasper.runtime.JspFactoryImpl.getPageContext(JspFactoryImpl.java:65)
at org.apache.jsp.error_jsp._jspService(error_jsp.java:53)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.Servlet.sendError(Servlet.java:56)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:57)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
12 20, 12 5:05:14 PM com.mycompany.mywebapp.servlet.CallDetailsServlet doRequest
ERROR: View failed
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:339)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:103)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
12 20, 12 5:05:15 PM com.mycompany.mywebapp.servlet.CallDetailsServlet doRequest
ERROR: View failed
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:339)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:103)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Dec 20, 2012 5:05:16 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.catalina.connector.Request.notifyAttributeAssigned(Request.java:1552)
at org.apache.catalina.connector.Request.access$000(Request.java:105)
at org.apache.catalina.connector.Request$3.set(Request.java:3342)
at org.apache.catalina.connector.Request.setAttribute(Request.java:1504)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:541)
at org.apache.catalina.core.ApplicationHttpRequest.setAttribute(ApplicationHttpRequest.java:281)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:286)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:103)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Dec 20, 2012 5:05:16 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [callDetailsServlet] in context with path [/WebCharts] threw exception
java.lang.NullPointerException
at org.apache.catalina.connector.Request.notifyAttributeAssigned(Request.java:1552)
at org.apache.catalina.connector.Request.access$000(Request.java:105)
at org.apache.catalina.connector.Request$3.set(Request.java:3342)
at org.apache.catalina.connector.Request.setAttribute(Request.java:1504)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:541)
at org.apache.catalina.core.ApplicationHttpRequest.setAttribute(ApplicationHttpRequest.java:281)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:286)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doRequest(CallDetailsServlet.java:103)
at com.mycompany.mywebapp.servlet.CallDetailsServlet.doGet(CallDetailsServlet.java:162)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:84)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
获取：
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
super.doGet(request, response);
doRequest(request);
}