开发工具:NetBeans6.8M1
注解支持

开发者可以用注解标记Servlet，Filter等，而不用在部署描述符web.xml文件中配置。随着注解的引入，部署描述符web.xml文件成为可选的。

现在创建Servlet相当简单：
UserServlet.java:

Java代码 收藏代码
package com.tanlan.servlet3;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 处理用户信息的Servlet
* @author tanlan tl_smile@163.com
* @date 2009-08-09
*/
@WebServlet(urlPatterns={“/UserServlet”})
public class UserServlet extends HttpServlet{
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String userName=request.getParameter(“userName”);
request.setAttribute(“userName”, userName);
//处理逻辑…
request.getRequestDispatcher(“result.jsp”).forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}

注解@WebServlet用于在Web应用程序中标记一个继承了HttpServlet的类为Servlet。其属性urlPatterns的值即是web.xml中的url-pattern。在地址栏输入如下的路径即可访问改Servlet:

http://localhost:8080/Javaee6web/UserServlet?userName=tanlan

创建过滤器如下
CharSetFilter.java:
Java代码 收藏代码
package com.tanlan.servlet3;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
/**
* 处理正文问题的Filter
* @author tanlan tl_smile@163.com
* @date 2009-08-09
*/

@WebFilter(urlPatterns={“/*”})
public class CharSetFilter implements Filter {
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
request.setCharacterEncoding(“UTF-8″);
chain.doFilter(request, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
}
public void destroy() {
}
}
注解@WebFilter用于在Web应用程序中标记一个实现了Filter接口的类为过滤器。

为Servlet或Filter配置初始化参数分别如下：
Java代码 收藏代码
@WebServlet(urlPatterns={“/UserServlet”},initParams={@WebInitParam(name=”name”,value=”Servlet’s tanlan”)})

@WebFilter(urlPatterns={“/*”},initParams={@WebInitParam(name=”name”,value=”Filter’s tanlan”)})

调用的代码分别为:
UserServlet.java:
Java代码 收藏代码
public void init(ServletConfig config) throws ServletException {
System.out.print(config.getInitParameter(“name”));
}
CharSetFilter.java:
Java代码 收藏代码
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println(filterConfig.getInitParameter(“name”));
}

http://tanlan.iteye.com/blog/443493