Servlet 3.0 @WebFilter and @WebServlet

Servlet 3.0 provides new annotation @WebFilter to simplify the configuration of a servlet filter. Here's a simple example and the filter will be invoked with url pattern "/student/*":

 

package com.jxee.action;

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;
import javax.servlet.http.HttpServletRequest;


@WebFilter(urlPatterns="/student/*")
public class TestFilter implements Filter {
  
  private FilterConfig filterConfig;

  @Override
  public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) 
      throws IOException, ServletException {
     System.out.println(">>>>>>>>>> start filter");
     String path = ((HttpServletRequest)req).getRequestURI();
     System.out.println(">>>>>>>>>> request URI: " + path);
     chain.doFilter(req, resp);
     System.out.println(">>>>>>>>>> exit filter");
  }

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
     this.filterConfig = filterConfig;
  }
  
  @Override
  public void destroy() {
    System.out.println(">>>>> have a nice one, bye!");
  }
}

 

Servlet 3.0 has similar annotation for servlet. Here's an example, this servlet can be invoked with two url patterns: "/test/myServlet" and "/testServ":

package com.jxee.action;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns={"/test/myServlet","/testServ"})
public class TestServlet extends HttpServlet {

  @Override
  public void doGet(HttpServletRequest req, HttpServletResponse resp) 
      throws IOException, ServletException {
    System.out.println("------ doGet(req,resp), i c u ------");
    this.doPost(req, resp);
  }
  
  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    System.out.println("------ doPost(req,resp), i c u ------");
    PrintWriter pw = new PrintWriter(resp.getOutputStream());
    pw.print("i c u!");
    pw.flush();
    pw.close();
  }
}