request的细节--学习笔记

Posted 2020-10-31

)转发是通过RequestDispatcher对象的forward(request,response)方法完成的

)forward()方法之前的输出，如果是输出到缓冲区，再转发到其他Servlet，那么原缓冲区的数据忽略不计

)forward()方法之前的输出，如果真正输出到浏览器，再转发到其他Servlet，再转发到其他Servlet代码忽略不计

)forward()方法之前的输出，如果是对响应头的设置，会保留到转发的其他Servlet中

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

public class Demo91 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        //response.setContentType("text/html;charset=UTF-8");
        //PrintWriter pw = response.getWriter();
        //pw.write("Demo91");
        //pw.flush();
        //pw.close();
        //转发
        //request.getRequestDispatcher("/Demo92").forward(request,response);
        //重定向
        response.sendRedirect("/day06/success.html");
    }
}

转发java

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 Demo92 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {

         //输出
        response.getWriter().write("Demo92");
    }
}