<error-page> 不适用于 servlet

Question

当 servlet 中的异常不工作但 jsp 它正常工作时

web.xml代码

<error-page>
<exception-type>java.lang.Throwable</exception-type>
<location>/error.jsp</location>
</error-page>

servlet 代码

protected void processRequest(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException 
{
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            /*
             * TODO output your page here. You may use following sample code.
             */
          String a=null;
          a.toString();//this line will throw exception
        } 
finally {            
            out.close();
        }
}

它不会重定向到 error.jsp

Answer 1

当我们在 servlet 中编写 catch 块时它不起作用，而当我们不编写 catch 块时它也能正常工作。 Servlet 代码

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        DAL db=null;
        ResultSet rs=null;
           parameter p1=new parameter();

          // Object param[];
          // List<Object> param=new ArrayList<Object>();
           long myId=0;
        try {


           db=new DAL();
           String name=request.getParameter("fn");
           db.setQuery("{call usp_StudentInsertData(?,?)}"); 
           db.setInParam(1,name);
           db.setInParam(2,1000);
           db.insertUpdate();
           out.println("insert");
           response.sendRedirect("home.jsp");
           } 
        catch(Exception e)
        {

        }
        finally {            
           }
    }

Answer 2

Servlet 代码这将抛出异常到一般错误页面

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
           // response.setContentType("text/html;charset=UTF-8");
            PrintWriter out = response.getWriter();
            try {
                /*
                 * TODO output your page here. You may use following sample code.
                 */
               String a=null;
               a.toString();

            }
            catch(Exception e)
            {
                throw new ServletException(e);
            }

            finally {            
                //dont write out.close();
            }
        }

<error-page> 不适用于 servlet

<error-page> is not working for servlet

java

apache

jsp

web.xml

servlets