Listener Filter Servlet回顾

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这是简单的案例，代码如下：
Listener:

import java.util.Enumeration;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyListener implements ServletContextListener {

	public void contextDestroyed(ServletContextEvent sce) {
		System.out.println("Listener Destory");
	}

	@SuppressWarnings("unchecked")
	public void contextInitialized(ServletContextEvent sce) {
		System.out.println("Listener Initialize");
		ServletContext servletContext = sce.getServletContext();
		Enumeration names = servletContext.getInitParameterNames();
		while (names.hasMoreElements()) {
			String name = names.nextElement();
			String value = servletContext.getInitParameter(name);
			System.out.println("param name : " + name + ",param value : " + value);
		}
	}

}

Filter:

import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class MyFilter implements Filter {

	public void destroy() {
		System.out.println("Filter destory");
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		chain.doFilter(request, response);
	}

	@SuppressWarnings("unchecked")
	public void init(FilterConfig filterConfig) throws ServletException {
		System.out.println("Filter init");
		Enumeration names = filterConfig.getInitParameterNames();
		while (names.hasMoreElements()) {
			String name = names.nextElement();
			String value = filterConfig.getInitParameter(name);
			System.out.println("param name : " + name + ",param value : " + value);
		}
	}

}

Servlet:

import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@SuppressWarnings("serial")
public class MyServlet extends HttpServlet{

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
			IOException {
		doPost(req, resp);
	}

	@SuppressWarnings("unchecked")
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		Enumeration names=this.getInitParameterNames();
		while(names.hasMoreElements()){
			String name=names.nextElement();
			String value=this.getInitParameter(name);
			System.out.println("param name : " + name + ",param value : " + value);
		}
	}
}

web.xml配置

  
      servlet context param
      servlet容器值
  
  
  
     myFilter
     MyFilter
     
        filter param
        过滤器值
     
  
  
  
      myFilter
      /*
  

  
     myServlet
     MyServlet
     
        servlet param
        servlet初始值
     
  
  
    myServlet
    /myServlet
  
  
  
  	MyListener