java - 将 HttpServletResponse 和 HttpServletRequest 存储为 HttpServlet 的两个字段

Question

将 HttpServletRequest 和 HttpServletResponse 临时存储为 HttpServlet 的两个字段(见下文)是否是一种好的做法/安全的做法？如果不是，为什么？

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

public class Test extends HttpServlet
    {
    private HttpServletRequest req;
    private HttpServletResponse resp;
    @Override
    protected void doPost(
            HttpServletRequest req,
            HttpServletResponse resp
            )
            throws ServletException, IOException
        {
        try
            {
            this.req=req;
            this.resp=resp;
            do1();
            do2();
            }
        finally
            {
            this.req=null;
            this.resp=null;
            }
        }

    private void do1() throws ServletException, IOException
        {
        //use req resp
        }
    private void do2() throws ServletException, IOException
        {
        //use req resp
        }
    }

或者我应该调用类似的东西:

do1(req,resp);
do2(req,resp);

Answer 1

Is it a good practice/safe to temporarily store the HttpServletRequest and the HttpServletResponse as two fields of a HttpServlet (see below) ?

不!

If not, why ?

因为 servlets 必须是线程安全的。多个线程将同时通过该 servlet 对象。如果您将请求/响应存储在字段中，您的线程安全性就会消失。

不要试图采取这种捷径来避免参数传递的视觉不愉快。

如果您真的必须避免使用参数，则将请求/响应存储在 java.lang.ThreadLocal 字段中。这仍然是不好的做法，但至少现在它是线程安全的。