一、创建ForwardServlet，用于请求转发
public class ForwardServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
request.getRequestDispatcher("/first.jsp").forward(request,
response);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}二、创建first.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<html>
<head></head>
<body>
first.jsp
</body>
</html>三、创建过滤器ForwardFilter
public class ForwardFilter implements Filter {
public void init(FilterConfig fConfig) throws ServletException {
// 过滤器对象在初始化时调用，可以配置一些初始化参数
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// 用于拦截用户的请求，如果和当前过滤器的拦截路径匹配，该方法会被调用
PrintWriter out=response.getWriter();
out.write("Hello FilterTest");
}
public void destroy() {
// 过滤器对象在销毁时自动调用，释放资源
}
}
四、配置过滤器
<filter>
<filter-name>ForwardFilter</filter-name>
<filter-class>cn.itcast.chapter08.filter.ForwardFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>ForwardFilter</filter-name>
<url-pattern>/first.jsp</url-pattern>
</filter-mapping>五、启动tomcat,请求ForwardServlet
http://localhost:8080/chapter08/ForwardServlet
说明没有拦截到ForwardServlet请求转发的first.jsp页面
六、增加配置，拦截请求转发
<filter-mapping>
<filter-name>ForwardFilter</filter-name>
<url-pattern>/first.jsp</url-pattern>
<dispatcher>FORWARD</dispatcher>
</filter-mapping>
