03 过滤器

1 web.xml

……
  <filter>
  	<filter-name>filter</filter-name>
  	<filter-class>test.MyFilter</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>filter</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>
……

2 MyFilter.java

package test;

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;

public class MyFilter implements Filter {

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

	public void doFilter(ServletRequest req, ServletResponse res,
			FilterChain chain) throws IOException, ServletException {
		System.out.println("do something");
		// 过滤器处理后,继续后面的流程
		chain.doFilter(req, res);
	}

	public void init(FilterConfig config) throws ServletException {
		System.out.println("initialize");
	}

}

3 test.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<title>Insert title here</title>
	</head>
	<body>
		test.jsp
	</body>
</html>


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