将错误处理从JSP替换为Servlet

Question

我的JSP脚本中有这段代码

<%@ page errorPage ="error.jsp"%>
<%!
  ...My JSP Code... //No matter for this question
%>

我的错误。jsp脚本是：

<%@ page isErrorPage = "true"%>
<% if (exception != null) { %>
  The cause of the exception error has been: 
        <% exception.printStackTrace(new java.io.PrintWriter(out)); %>
<% } %>

比如：http://www.tutorialspoint.com/jsp/jsp_exception_handling.htm

但我想替换servlet之前的所有代码。。。

正如你所见。。。

我需要翻译

error.jsp完全...例如如何翻译这个：

对不起，但是我不知道怎么做...

PD：我在寻找我的问题，但网站告诉我需要改变网站。xml文件，我不想这样做，我认为（我的JSP脚本工作得很好，Tomcat servlet转换的也很好，不需要更改该文件）。

Answer 1

嘿，伙计，路易吉·朱塞佩。是的，@mikemil告诉right buddy，你应该只使用try/catch，否则使用该方法显示异常错误，如下代码所示：

package com.jmail.servlet.exception;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/MyExceptionServlet")
public class MyExceptionServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        throw new ServletException("GET method is not supported.");
    }
}

现在，您只会得到这样的错误页面：

GET method is not supported.

Answer 2

嘿，伙计，路易吉·朱塞佩。我想这件事会让你满意的。

在Java web应用程序中定义错误页面的两种方法是使用Servlet和JSP编写的，与您的问题相关。

 1. First way is page wise error page which is defined on each jsp page and if there is any unhanded exception thrown from that page, corresponding error page will be displayed. 

 2. Second approach is an application wide general or default error page which is shown if any Exception is thrown from any Servlet or JSP and there is no page specific error page defined.

HTTP标准错误代码：

 1. Information This one is a new return code which is not 100%
    supported and normally and only provides information to the client
    about the request.

 2. Success response, the request has been correctly executed ->
    expected answer from server (http code 200).

 3. Redirection response. The resource has moved and is not any more at
    this URL.

 4. Error on client side. Probably most known of all is error 404 : Not
    Found.

定义错误。jsp页面，如：

//error.jsp
<%@ page isErrorPage="true"%>
//login.jsp
<%@ page errorPage="error.jsp"%>

Java Web应用程序JSP Servlet页面中的错误页面如下所示：

基于异常的默认错误页面：

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

基于HTTP错误代码的默认错误页：

<error-page>
    <error-code>500</error-code>
    <location>/internal-server-error.htm</location>
</error-page>
<error-page>
    <error-code>404</error-code>
    <location>/page-not-found-error.htm</location>
</error-page>

创建自定义错误页面：

 1. 400.html -> telling the user did something wrong

 2. 500.html -> telling the server did something wrong

400.html：

<error-page>
        <error-code>400</error-code>
        <location>/404.html</location>
 </error-page>
 <error-page>
        <error-code>401</error-code>
        <location>/404.html</location>
 </error-page>

500.html：

     <error-page>
          <error-code>500</error-code>
          <location>/500.html</location>
       </error-page>
       <error-page>
          <error-code>501</error-code>
          <location>/500.html</location>
       </error-page>