Servlet 转发和重定向

最新推荐文章于 2023-12-28 14:16:25 发布

原创最新推荐文章于 2023-12-28 14:16:25 发布 · 224 阅读

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本文深入探讨了Servlet中两种重要的请求处理方式：转发和重定向。通过具体代码示例，详细解析了这两种机制的工作原理及其区别。转发是在服务器内部进行的页面跳转，可以传递request对象中的属性；而重定向则涉及到客户端重新发起请求，原request域内容无法获取。

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获得数据Servlet:

package com.example.demo.learn.servlet.forward;

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

/**
 * 获得数据的Servlet
 */
@WebServlet("/GetDataServlet")
public class GetDataServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = (String) req.getAttribute("name");
        System.out.println("获取的name是: " + name);
    }
}

转发：

package com.example.demo.learn.servlet.forward;

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

/**
 * 转发请求
 *     跳转有两种方式，一是转发，一个是重定向
 */
@WebServlet("/ForwardServlet")
public class ForwardServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setAttribute("name", "song");
        // 转发时将request对象传过去了
        req.getRequestDispatcher("/GetDataServlet").forward(req,resp);
    }
}

重定向：

package com.example.demo.learn.servlet.forward;


import com.sun.deploy.net.HttpResponse;
import org.springframework.http.HttpStatus;

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

/**
 * servlet重定向
 *    返回302状态，客户端接收后，再次发送请求，原先的request域内容也无法获取
 */
@WebServlet("/RedirectServlet")
public class RedirectServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setAttribute("name", "song");

        // resp.sendRedirect(this.getServletContext().getContextPath() + "/GetDataServlet");

        // 手动实现重定向
        resp.setStatus(HttpServletResponse.SC_FOUND);
        resp.setHeader("Location",this.getServletContext().getContextPath() + "/GetDataServlet");
    }
}