我该如何解决这个问题？我尝试了很多东西，并在这里看了很多不同的东西，同样的问题，但我无法解决它。有人可以解释发生了什么。如果它有帮助，我希望客户提交一个表单，一旦它们进入servlet并将其发送到收据，他们会看到他们输入的信息。如果有一个更容易的解决方案，我会全力以赴。
下面是stacktrace
Mar 31, 2014 2:40:17 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [edu.witc.Assignment03.controller.CustomerServlet] in context with path [/Justin_EJ_Assignment03_15400579] threw exception
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:348)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at edu.witc.Assignment03.controller.CustomerServlet.sendCustomerInfo(CustomerServlet.java:85)
at edu.witc.Assignment03.controller.CustomerServlet.doPost(CustomerServlet.java:139)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
package edu.witc.Assignment03.controller;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//import javax.servlet.annotation.WebServlet;
//import javax.servlet.http.HttpServlet;
//import javax.servlet.http.HttpServletRequest;
//import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import edu.witc.Assignment03.model.Customer;
import edu.witc.Assignment03.model.Phone;
import edu.witc.Assignment03.model.States;
@WebServlet(description = "servlet to get act as controller between form and models", urlPatterns = { "/customerServlet" })
public class CustomerServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CustomerServlet() {
super();
}
private void processRequest(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
HttpSession session = request.getSession();
//create the JavaStudents object
Phone phone = new Phone();
//declare the student collection
Collection<Phone> phones = phone.getPhoneCollection();
//flesh out the collection from the arraylist
//students = new JavaStudents().getStudents();
//System.out.println("hey " + students.size());
//store the JavaStudents object in the session
//if(session != null){
session.setAttribute("phones", phones);
request.getRequestDispatcher("/customerManagement.jsp").forward(request, response);
//}
}
private edu.witc.Assignment03.model.States states = new States();
private List<edu.witc.Assignment03.model.Customer> customers = new ArrayList<Customer>();
private void addCustomer(HttpServletResponse response, HttpServletRequest request)//redirect to index
throws IOException, ServletException {
String url = "/receipt.jsp";
request.setAttribute("customers", customers);
request.getRequestDispatcher(url).forward(request,response);
}
private void editCustomer(HttpServletResponse response, HttpServletRequest request)//redirect to index
throws IOException, ServletException {
String url = "/customerManagement.jsp";
request.setAttribute("customers", customers);
request.getRequestDispatcher(url).forward(request,response);
}
private void sendCustomerInfo(HttpServletResponse response, HttpServletRequest request)//redirect to index
throws IOException, ServletException {
String url = "/receipt.jsp";
request.setAttribute("customers", customers);
request.getRequestDispatcher(url).forward(request,response);
}
private Customer getCustomer(int customerId) {
for (Customer customer : customers) {
if (customer.getCustomerId() == customerId) {
return customer;
}
}
return null;
}
private void sendEditCustomerForm(HttpServletRequest request,
HttpServletResponse response) throws IOException, ServletException {
String url = "/customerManagement.jsp";
request.setAttribute("customers", customers);
request.getRequestDispatcher(url).forward(request,response);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
// update customer
int customerId = 0;
try {
customerId =
Integer.parseInt(request.getParameter("id"));
} catch (NumberFormatException e) {
}
Customer customer = getCustomer(customerId);
if (customer != null) {
customer.setFirstName(request.getParameter("firstName"));
customer.setLastName(request.getParameter("lastName"));
customer.setEmail(request.getParameter("email"));
customer.setPhone(request.getParameter("phone"));
customer.setAddress(request.getParameter("address"));
customer.setCity(request.getParameter("city"));
customer.setZip(request.getParameter("zip"));
}
sendCustomerInfo(response, request);
}
}
答案 0 :(得分：2)
在doPost()方法中，您使用以下两种方法发送回复
processRequest(request, response);
sendCustomerInfo(response, request);
因此，在调用sendCustomerInfo(response, request)时，您将获得此异常，因为processRequest方法已经提交了响应
答案 1 :(得分：0)
如果没有看到任何代码，很难告诉你该做什么。然而，正在发生的是：
edu.witc.Assignment03.controller.CustomerServlet.sendCustomerInfo(CustomerServlet.java:85)
您要将回复转发给其他人。
但您之前已在回复中发送了一些内容。你无法做到的。您必须发送回复，或将请求转发给其他人。你不能做到这两点。