Java8设计模式最佳实战-设计模式概述（第六天学习记录）

create a filter called LogBrowserFilter.

创建一个名为LogBrowserFilter的筛选器来过滤浏览器信息。

Implementing LogAccessFilter

Here, we have the implementation of LogAccessFilter:

package com.gary.book.chapter01;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.Logger;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

import java.util.Date;

@WebFilter(filterName = “LogAccess”, urlPatterns = “/*”)

public class LogAccessFilter implements javax.servlet.Filter {

private static Logger logger =

LogManager.getLogger(LogAccess.class);

public void destroy() {

}

public void doFilter(javax.servlet.ServletRequest req,

javax.servlet.ServletResponse resp, javax.servlet.FilterChain

chain) throws javax.servlet.ServletException, IOException {

//Gets the initial date of request.

Date dateInitRequest = new Date();

//Get IP of Client that sent a resquest.

String ip = ((HttpServletRequest) req).getRemoteAddr();

//Following to next filter. If none next filter exist, follows

//for main logic.

chain.doFilter(req, resp);

//Gets the end date of request.

Date dateEndRequest = new Date();

//Logging the informations of IP and access time.

logger.info("IP: " + ip + " Access time : "

• Long.toString(dateEndRequest.getTime()

• dateInitRequest.getTime())

• " ms");

}

public void init(javax.servlet.FilterConfig config) throws

javax.servlet.ServletException {

}

}

As we can see in the code, to create one servlet filter, we need to create a class that

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