关于Javaweb的转发和重定向详解

request.getRequestDispatcher("/目标URL-pattern").forward(request,response);
//跳转转发到login.jsp
req.getRequestDispatcher("login.jsp").forward(req,resp);

request.setAttribute(key,value);

request.getAttribute(key)

//request作用域存储数据
req.setAttribute("admins",adminList);
//request作用取数据
request.getAttribute("admins");

// response.sendRedirect("目标URL")；
resp.sendRedirect("index.jsp");		//重定向跳转到index.jsp页面

//传递数据
resp.sendRedirect("/WebProject_war_exploded/b?username=tom");   //传递数据为String类型，明文传递
//获取数据
String username = req.getParameter("username");

package com.woniu.servlet2;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;
@WebServlet(value = "/ls")
public class LifeServlet implements Servlet {
    public LifeServlet(){
        System.out.println("1.实例化");
    }
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("2.初始化");
    }
    @Override
    public ServletConfig getServletConfig() {
        return null;
    }
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("3.提供服务，接受请求，响应结果");
    }
    @Override
    public String getServletInfo() {
        return null;
    }
    @Override
    public void destroy() {
        System.out.println("4.销毁");
    }
}