request内部转发Demo

// 转发的Demo1

import javax.servlet.RequestDispatcher;
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;
@WebServlet("/sendData")
public class Demo1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //资源跳转 把一个服务当中的数据带到另外一个服务当中页面中
        String name="小孙";
        //http资源对象的内部转发方式
        RequestDispatcher dispatcher = req.getRequestDispatcher("receiveData");

        //域 缓存
        // request域 存储的时机就是这个一次请求中，当请求结束的时候request域对象信息就释放掉了
        req.setAttribute("username",name);//key - value
        //转发
        dispatcher.forward(req,resp);
    }
}

// 接收的Demo2

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;
@WebServlet("/receiveData")
public class Demo2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //从request中获取value值
        String name = (String) req.getAttribute("username");
        //如果携带有中文信息 设定编码字符集
        //System.out.println(name);
        resp.setContentType("text/html;charset=utf-8");
        //显示在页面中
        resp.getWriter().write(name);
    }
}