转发
①创建Servlet1 和Servlet2的Java文件
package zhuan;
import java.io.IOException;
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;
@WebServlet(value="/aaa")
public class Servlet1 extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取前台传过来的信息
String username = req.getParameter("username");
System.out.println(username);
/***
* 1.请求转发必须以斜杠开头，斜杠表示http://ip:port/工程名/ 。映射到web目录
* 2.※※※※※请求转发也可以转发到Web工程下： req.getRequestDispatcher("/a/index.html");
* ※※※※※需要注意的是 如果在a/index.html中存在超链接返回到另一个界面 通常需要使用base标签来设置当前页面的相对路径参照的地址
* ※※※※※在<head></head>中定义<base href="http://localhost:8080/项目名/a/index.html">
*/
RequestDispatcher requestDispatcher = req.getRequestDispatcher("/servlet2");
requestDispatcher.forward(req, resp);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
}
package zhuan;
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 Servlet2 extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("我是Servlet2");
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
}②配置web.xml文件
<!-- servlet1 -->
<servlet>
<servlet-name>Servlet1</servlet-name>
<servlet-class>zhuan.Servlet1</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Servlet1</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>
<!-- servlet2 -->
<servlet>
<servlet-name>Servlet2</servlet-name>
<servlet-class>zhuan.Servlet2</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Servlet2</servlet-name>
<url-pattern>/servlet2</url-pattern>
</servlet-mapping>重定向
请求重定向的两种方式：
- 方式一：设置响应头
resp.setStatus(302);
resp.setHeader("Location", "/response2");
- 方式二：使用servlet提供的ap(推荐使用)
resp.sendRedirect("response2");