所以，我所做的是调用 servlet(purchasecreate.java)，然后它应该将我重定向到 purchaseCreateM.jsp。我不知道出了什么问题，但每次我运行时，它都会将我重定向到 PurchaseCreate 的空白页面。因此，我取消了 RequestDispatcher 并转发以检查程序可以运行多远。该程序能够完全运行，但是当我重新设置调度程序时，它再次将我带到空白页面。任何人都可以帮助我吗？
购买创建.java
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
Members member = new Members();
Stocks stock = new Stocks();
Purchase purc = new Purchase();
String purcid = "";
stock.setStockid(request.getParameter("stockid"));
String stockid = stock.getStockid();
String purcdid = "";
int quantity = 0 ;
PrintWriter out = response.getWriter();
try{
out.println(stockid);
out.println("Hello");
int idNum = GeneratePdid();
if(idNum<10)
purcdid = "PD0000"+String.valueOf(idNum);
else if(idNum<100)
purcdid = "PD000"+String.valueOf(idNum);
else if(idNum<1000)
purcdid = "PD00"+String.valueOf(idNum);
else if(idNum<10000)
purcdid = "PD0"+String.valueOf(idNum);
else if(idNum<100000)
purcdid = "PD"+String.valueOf(idNum);
int PidNum = GeneratePid();
if(PidNum<10)
purcid = "P000"+String.valueOf(PidNum);
else if(PidNum<100)
purcid = "P00"+String.valueOf(PidNum);
else if(PidNum<1000)
purcid = "P0"+String.valueOf(PidNum);
else if(PidNum<10000)
purcid = "P"+String.valueOf(PidNum);
out.println("Hello");
out.println(stockid);
stock.setStockid(stockid);
out.println(purcid);
purc.setPurchaseid(purcid);
out.println(purcdid);
out.println("Hello");
quantity = Integer.parseInt(request.getParameter("quantity"));
out.println(quantity);
Purchasedetails purchased = new Purchasedetails(purcdid,quantity,stock,purc);
out.println(stock);
out.println(purc);
Query query = em.createNamedQuery("Purchasedetails.findAll");
List<Purchasedetails> listDetails = query.getResultList();
Query query2 = em.createNamedQuery("Stocks.findAll");
List<Stocks> stockPrice = query2.getResultList();
double stockPriceReal = 0;
for(int i = 0 ; i <stockPrice.size(); i++){
String stockid2 = stockPrice.get(i).getStockid();
if(stockid2.equals(stockid))
{
stockPriceReal = Double.parseDouble(stockPrice.get(i).getStockprice().toString());
}
}
out.print(stockPriceReal);
HttpSession session = request.getSession();
request.setAttribute("listDetails",listDetails);
request.setAttribute("stockPriceReal",stockPriceReal);
out.print(stockPriceReal);
// response.sendRedirect("MemberAccess/PurchaseCreateM.jsp");
RequestDispatcher rd = request.getRequestDispatcher("MemberAccess/PurchaseCreateM.jsp");
rd.forward(request, response);
} catch (Exception ex) {
Logger.getLogger(PurchaseCreate.class.getName()).log(Level.SEVERE, null, ex);
}
finally{
out.close();
}
}
public int GeneratePid(){
Query query = em.createNamedQuery("Purchase.findAll");
List<Purchase> purchaseList = query.getResultList();
String lastId = "";
if(!purchaseList.isEmpty()){
lastId = purchaseList.get(purchaseList.size()-1).getPurchaseid();
}
System.out.println(lastId);
String subString = lastId.substring(1,4);
int realId = Integer.parseInt(subString) +1;
return realId;
}
public int GeneratePdid(){
Query query = em.createNamedQuery("Purchasedetails.findAll");
List<Purchasedetails> purchaseDetailsL = query.getResultList();
String lastId = "";
if(!purchaseDetailsL.isEmpty()){
lastId = purchaseDetailsL.get(purchaseDetailsL.size()-1).getPurchasedetailid();
}
String subString = lastId.substring(2,6);
int realId = Integer.parseInt(subString) +1;
return realId;
}
购买创建.jsp
<%@page import="java.util.ArrayList"%>\
<%@page import="model.*"%>
<%@page import="java.util.List"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<html>
<head>
<title>Cart</title>
</head>
<% List<Purchasedetails> list = (List<Purchasedetails>)request.getAttribute("listDetails"); %>
<% double StockPrice = (double)request.getAttribute("stockPriceReal"); %>
<%! double stockArray[]; %>
<% if(stockArray.length == 0)
stockArray[0] = StockPrice;
else
for(int i = 0; i <stockArray.length;i++)
stockArray[i] = StockPrice;
%>
<% int size= list.size(); %>
<%! String pDID = "";%>
<%! int pDIDno = 0; %>
<%! String pDIDSub = ""; %>
<%! String pDIDreal = ""; %>
<body>
<% if (size != 1){ %>
<% pDID = list.get(list.size()-1).getPurchasedetailid(); %>
<% pDIDSub = pDID.substring(2, 6); %>
<% pDIDno = Integer.parseInt(pDIDSub) + (size-1);}%>
<% if(pDIDno<10)
pDIDreal = "PD0000"+pDIDno;
else if(pDIDno<100)
pDIDreal = "PD000"+ String.valueOf(pDIDno);
else if(pDIDno<1000)
pDIDreal = "PD00"+ String.valueOf(pDIDno);
else if(pDIDno<10000)
pDIDreal = "PD0"+ String.valueOf(pDIDno);
else if(pDIDno<100000)
pDIDreal = "PD"+String.valueOf(pDIDno);
Purchasedetails pd = new Purchasedetails(pDIDreal);
// list.get(list.size()-1).setPurchasedetailid(pDIDreal);
list.set(list.size()-1, pd);
%>
<table border="1">
<thead>
<tr>
<th>No.</th>
<th>Purchase Details ID</th>
<th>Stock ID</th>
<th>Quantity</th>
<th>Price</th>
</tr>
</thead>
<tbody>
<% for (int i = 0; i <list.size(); i++) { %>
<tr>
<td><%= i+1 %></td>
<td><%= list.get(i).getPurchasedetailid() %></td>
<td><%= list.get(i).getStockid() %></td>
<td><%= list.get(i).getOrderqty() %></td>
<td><%= stockArray[i] %></td>
</tr>
<% i++;%>
<% } %>
</tbody>
</table>
</body>
</html>
编辑（14 年 15 月 12 日）：这是打印在服务器日志上的内容。
[2014-12-15T01:07:06.526+0800] [glassfish 4.0] [SEVERE] [] [] [tid: _ThreadID=107 _ThreadName=Thread-4] [timeMillis: 1418576826526] [levelValue: 1000] [[
org.apache.jasper.JasperException: PWC6033: Error in Javac compilation for JSP
PWC6199: Generated servlet error:
source value 1.5 is obsolete and will be removed in a future release
PWC6199: Generated servlet error:
target value 1.5 is obsolete and will be removed in a future release
PWC6199: Generated servlet error:
To suppress warnings about obsolete options, use -Xlint:-options.
PWC6197: An error occurred at line: 20 in the jsp file: /MemberAccess/PurchaseCreateM.jsp
PWC6199: Generated servlet error:
incompatible types: java.lang.Object cannot be converted to double
PWC6199: Generated servlet error:
/PurchaseCreateM_jsp.java uses unchecked or unsafe operations.
PWC6199: Generated servlet error:
Recompile with -Xlint:unchecked for details.
at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:129)
at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:299)
at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:392)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:453)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:625)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:473)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:377)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.ApplicationDispatcher.doInvoke(ApplicationDispatcher.java:875)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:739)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:575)
at org.apache.catalina.core.ApplicationDispatcher.doDispatch(ApplicationDispatcher.java:546)
at org.apache.catalina.core.ApplicationDispatcher.dispatch(ApplicationDispatcher.java:428)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:378)
at controller.PurchaseCreate.doPost(PurchaseCreate.java:106)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:745)]]