Question

我知道这里已经讨论了至少一百万次但是每个servlet在调用forward（）之前重定向或刷新输出。我有同样的问题，但我没有做任何输出。我的servlet只接受请求参数并提交到数据库并在请求上设置属性。然后，它将请求转发给它们显示属性的jsp。我在Tomcat 7上使用Servlet 3.0。这是我的servlet doPost方法，然后是转发到的jsp：

@Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        super.doPost(req, resp);

        DAOFactory daoFactory = DAOFactory.getFactory();
        daoFactory.getCompanyDAO().beginTransaction();

        Company company = new Company();
        company.setName(req.getParameter("companyName"));
        company.setContactEmail(req.getParameter("companyEmail"));
        company.setContactPhone(new Long(req.getParameter("companyMobile")));
        company.setAddressLine1(req.getParameter("companyAddressLine1"));
        company.setAddressLine2(req.getParameter("companyAddressLine2"));
        company.setCity(req.getParameter("companyCity"));
        company.setZipcode(Integer.parseInt(req.getParameter("companyZip")));
        company.setState(req.getParameter("companyState"));     
        company = daoFactory.getCompanyDAO().save(company);
        daoFactory.getCompanyDAO().commitTransaction();

        Employee owner = new Employee();
        owner.setFirstname(req.getParameter("ownerFirstName"));
        owner.setLastname(req.getParameter("ownerLastName"));
        owner.setEmail(req.getParameter("ownerEmail"));
        owner.setMobileNum(new Long(req.getParameter("ownerCellPhone")));
        owner.setZipcode(Integer.parseInt(req.getParameter("ownerZip")));
        owner.setRole("Employer");
        owner.setCompany(company);
        daoFactory.getEmployeeDAO().beginTransaction();
        owner = daoFactory.getEmployeeDAO().save(owner);
        daoFactory.getEmployeeDAO().commitTransaction();

        company.addEmployee(owner);
        company.setOwnerId(owner.getId());

        daoFactory.getCompanyDAO().beginTransaction();
        company = daoFactory.getCompanyDAO().save(company);
        daoFactory.getCompanyDAO().commitTransaction();

        req.setAttribute("company", company);
        RequestDispatcher rd = getServletConfig().getServletContext().getRequestDispatcher("/jsp/companyConfirmation.jsp");
        rd.forward(req, resp);

    }

JSP：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h3>The Company was saved successfully</h3>
<p>
Company name: ${company.name}
</p>
</body>
</html>

我相信我可能错过了一些非常微不足道的事情。我无法弄清楚它是什么，特别是当我在转发请求之前没有向输出写任何内容时。

PS：我也尝试在前进后添加return;语句，但没有变化。

谢谢！

Answer 1

您应该删除super.doPost(req, resp)方法调用。 HTTPServlet的doPost方法的默认实现返回HTTP 405状态代码，意思是“不支持方法”，这是已提交的响应。因此，您无法将您的请求转发给其他jsp。

这是RequestDispatcher.forward(ServletRequest req, ServletResponse resp)方法描述的一部分：“应该在将响应提交给客户端之前调用forward（在刷新响应主体输出之前）。如果响应已经提交，则此方法抛出IllegalStateException。响应缓冲区中的未提交输出在转发前自动清除。

java.lang.IllegalStateException：在提交响应后无法转发

1 个答案: