请求重定向的第一种方案:

准备两个servlet程序

Response1

public class Response1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        System.out.println("Hello Response1");
        //设置响应状态码302,表示垂定向,(已搬迁)
        resp.setStatus(302);

        //设置响应头,说明新的地址在哪里
//        resp.setHeader("location","http://localhost:8080/servlet/response2");
        //可以访问工程以外的地址   ,但是不能访问WEB-INF里面的内容
        resp.setHeader("location","http://www.baidu.com");

    }
}

Response2

public class Response2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

      resp.getWriter().write("response2' s result!");
    }
}

xml配置

  <servlet>
        <servlet-name>Response1</servlet-name>
        <servlet-class>com.example.servlet.Response1</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Response1</servlet-name>
        <url-pattern>/response1</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>Response2</servlet-name>
        <servlet-class>com.example.servlet.Response2</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Response2</servlet-name>
        <url-pattern>/response2</url-pattern>
    </servlet-mapping>

请求重定向的第二种方案:

public class Response1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        System.out.println("Hello Response1");
        //设置响应状态码302,表示垂定向,(已搬迁)
//        resp.setStatus(302);

        //设置响应头,说明新的地址在哪里
//        resp.setHeader("location","http://localhost:8080/servlet/response2");
        //可以访问工程以外的地址   ,但是不能访问WEB-INF里面的内容
//        resp.setHeader("location","http://www.baidu.com");

        //第二种方法
        //直接写地址就可以 302是固定的不需要设置
        resp.sendRedirect("http://www.baidu.com");
    }
}