Request域对象

通过该对象可以在一个请求中传递数据，作用范围：在一次请求中有效，即服务器跳转有效。

package com.mage.hsr;
/*	
 * request域对象
 * */
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 Test03 extends HttpServlet {
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("uname","qwe");
		//使用域对象前必须先使用set设置内容
		Object uname2 = req.getAttribute("uname");
		//通过键名，得到值
		System.out.println(uname2);
		req.getRequestDispatcher("hsr04").forward(req,resp);
		//请求转发，将req对象，转发给其他页面(Test04)
		req.removeAttribute("uname");
		//移除uname域对象
		System.out.println(uname2);
	}
}

public class Test04 extends HttpServlet {
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		
		System.out.println("hello"+req.getAttribute("uname"));
		//输出Test03请求转发过来的域对象内容
	}
}