（1）从JSP调用Servlet可用<jsp:forward>，请求信息自动转到Servlet
FromJspToServlet.jsp
<html>
<body bgcolor="green">
<!-- Forward to a servlet, 这个servlet存放在web-inf的servlet目录下 -->
<jsp:forward page="/servlet/ServletToJSP" />
</body>
</html>
（2）从Servlet调用JSP可以使用RequestDispatcher接口的forward(req, resp)方法，请求信息需要显示传递
ServletToJSP.java
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 ServletToJSP extends HttpServlet {
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 设置属性并将它分发给/servlet_jsp/ServletUseJsp.jsp处理
resp.setContentType("text/html;charset=gb2312");
req.setAttribute("servletName", "ServletToJSP");
// RequestDispatcher getRequestDispatcher(String path):
// Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path.
getServletConfig().getServletContext().getRequestDispatcher("/servlet_jsp/ServletUseJsp.jsp").forward(req, resp);
}
}
（3）ServletUseJsp.jsp
<%@page contentType="text/html;charset=gb2312" %>
<html>
<meta context="text/html;charset=gb2312">
<head>
<title>Servlet使用JSP</title>
</head>
<body bgcolor="gray">
<h2>Servlet使用JSP的例子</h2>
<h2>这个页面是被Servlet调用的</h2>
</body>
</html>
说明：以上相互调用也可以直接使用sendRedirect