Ruquest请求转发
请求转发(forward)：一种在服务器内部的资源跳转方式
实现方式：
req.getRequestDispatcher("资源B路径").forward(req,resp);
请求转发资源间共享数据：使用Request对象
void setAttribute(String name,Object o)：存储数据到request域中
Object getAttribute(String name)：根据key，获取值
void removeAttribute(String name)：根据key，删除该键值对
代码示例：
RequestDemo05：
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; /** * 请求转发 */ @WebServlet("/req5") public class RequestDemo5 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("demo5..."); //存储数据 request.setAttribute("msg","hello"); //请求转发 request.getRequestDispatcher("/req6").forward(request,response); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } }
Request06：
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; /** * 请求转发 */ @WebServlet("/req6") public class RequestDemo6 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("demo6..."); //获取数据 Object msg = request.getAttribute("msg"); System.out.println(msg); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } }
执行结果：
URL访问req5：
控制台输出请求转发的数据：
请求转发特点：
1、浏览器地址栏不发生变化
2、只能转发到当前服务器的内部资源
3、一次请求，可以在转发的资源间使用request共享数据
