1 @WebServlet("/cdiservlet")      //url映射 2 public class NewServlet extends HttpServlet { 3     private Message message; 4  5     @Override             //重写doGet方法 6     public void init() { 7         message = new MessageB();    //对message初始化 8     } 9 10     @Override11     public void doGet(HttpServletRequest request, HttpServletResponse response)12                   throws IOException {              //抛出可能出现IO异常13         response.getWriter().write(message.get());   //捕获可能发生的异常14     }15 }16 17 public interface Message {         //servlet实现Message接口的一个对象实例18     public String get();19 }20 public class MessageB implements Message {          //servlet创建以下对象的实例21     public MessageB() { }22 23     @Override24     public String get() {25         return "message B";26     }27 }28 @WebServlet("/cdiservlet")              //使用CDI，servlet声明它对Message实例的依赖性，并让它由CDI运行时自动注入29 public class NewServlet extends HttpServlet {30     @Inject private Message message;31 32     @Override33     public void doGet(HttpServletRequest request, HttpServletResponse response)34                   throws IOException {       //抛出可能出现IO异常35           response.getWriter().write(message.get());  //捕获可能发生的异常36  }37 }