本文簡要介紹如何實作一個IP通路計數器。
為了簡單, 使用 JSP 來實作, 但讀者需要明白, Java代碼可以在到處運作。
示例Demo頁面:
http://www.cncounter.com/test/counter.jsp 傳回JSON: http://www.cncounter.com/test/counter.jsp?format=json 清空本IP的計數: http://www.cncounter.com/test/counter.jsp?action=clear下面列出實作代碼, 文檔和說明就在代碼中:
解析用戶端IP的工具類
IPUtils.java
: package com.cncounter.util.net;
import javax.servlet.http.HttpServletRequest;
/**
* IP工具類
*/
public class IPUtils {
public static final String SEMICOLON = ";";
// Nginx代理傳遞的實際用戶端 IP-header
public static final String[] HEADERS_TO_TRY = {
"X-Forwarded-For",
"X-REAL-IP",
"Proxy-Client-IP",
"WL-Proxy-Client-IP",
"HTTP_X_FORWARDED_FOR",
"HTTP_X_FORWARDED",
"HTTP_X_CLUSTER_CLIENT_IP",
"HTTP_CLIENT_IP",
"HTTP_FORWARDED_FOR",
"HTTP_FORWARDED",
"HTTP_VIA",
"REMOTE_ADDR",
"REMOTE-HOST"
};
/**
* 擷取用戶端的IP位址
*/
public static String getClientIp(HttpServletRequest request) {
String clientIp = _getClientIp(request);
if (null != clientIp && !clientIp.trim().isEmpty()) {
return clientIp;
}
return request.getRemoteAddr();
}
private static String _getClientIp(HttpServletRequest request) {
for (String header : HEADERS_TO_TRY) {
String ip = request.getHeader(header);
if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {
return ip;
}
}
return request.getRemoteAddr();
}
}
其中依賴了 FastJSON, FastJSON的資訊請參考:
https://github.com/alibaba/fastjson/wiki/Quick-Start-CN改為其他JSON庫也可以。但強烈推薦使用簡單強大靈活的FastJSON。
JSP檔案
counter.jsp
實作代碼如下:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8" isErrorPage="true" %>
<%@ page trimDirectiveWhitespaces="true" %>
<%@ page import="java.util.concurrent.ConcurrentHashMap" %>
<%@ page import="java.util.concurrent.atomic.AtomicInteger" %>
<%@ page import="com.cncounter.util.net.IPUtils" %>
<%@ page import="com.alibaba.fastjson.JSON" %>
<%-- trimDirectiveWhitespaces 的作用是去除多餘的空行 --%>
<%!
// 通路計數器Map<IP位址, 次數>
private static ConcurrentHashMap<String, AtomicInteger> visitCounterMap
= new ConcurrentHashMap<String, AtomicInteger>();
// 增加并擷取最新的通路次數
private static int incrementCounter(String clientIp) {
//
AtomicInteger visitCounter = visitCounterMap.get(clientIp);
if (null == visitCounter) {
visitCounter = new AtomicInteger();
AtomicInteger oldValue = visitCounterMap.putIfAbsent(clientIp, visitCounter);
if (null != oldValue) {
// 使用 putIfAbsent 時注意: 判斷是否有并發導緻的原有值。
visitCounter = oldValue;
}
}
// 先增加, 再傳回
int count = visitCounter.incrementAndGet();
return count;
}
// 清除某個IP的通路次數
private static int clearCounter(String clientIp) {
visitCounterMap.remove(clientIp);
return 0;
}
//
private static final String CONST_PARAM_NAME_ACTION = "action";
private static final String CONST_ACTION_VALUE_CLEAR = "clear";
//
private static final String CONST_PARAM_NAME_FORMAT = "format";
private static final String CONST_FORMAT_VALUE_JSON = "json";
//
private static final String CONST_ATTR_NAME_CLIENTIP = "clientIp";
private static final String CONST_ATTR_NAME_VISITCOUNT = "visitCount";
%>
<%
// 擷取用戶端IP位址
String clientIp = IPUtils.getClientIp(request);
Integer visitCount = 0;
if (null != clientIp) {
// 擷取通路次數
visitCount = incrementCounter(clientIp);
}
// 如果需要清空資料
String action = request.getParameter(CONST_PARAM_NAME_ACTION);
if (CONST_ACTION_VALUE_CLEAR.equalsIgnoreCase(action)) {
visitCount = clearCounter(clientIp);
}
// 如果需要傳回JSON格式的資料
String format = request.getParameter(CONST_PARAM_NAME_FORMAT);
if (CONST_FORMAT_VALUE_JSON.equalsIgnoreCase(format)) {
// 傳回JSON
Map<String, Object> result = new HashMap<String, Object>();
result.put(CONST_ATTR_NAME_CLIENTIP, clientIp);
result.put(CONST_ATTR_NAME_VISITCOUNT, visitCount);
%>
<%=JSON.toJSONString(result)%>
<%
return; // 如果傳回JSON資料, 則不往下執行
}
%>
<HTML>
<HEAD>
<TITLE>統計頁面通路次數</TITLE>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="viewport"
content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<style>
body {
word-wrap: break-word;
word-break: break-all;
}
</style>
</HEAD>
<BODY>
<H1>統計頁面通路次數</H1>
<table border="1" width="100%">
<thead>
<tr>
<td align="center">
<h3>IP位址</h3>
</td>
<td align="center">
<h3>通路次數</h3>
</td>
</tr>
</thead>
<tbody>
<%
Set<String> keySet = visitCounterMap.keySet();
// 排序?
// 根據值排序?
for (String key : keySet) {
%>
<tr>
<td>
<%=key%>
</td>
<td>
<%=visitCounterMap.getOrDefault(key, new AtomicInteger(0)).intValue()%>
</td>
</tr>
<%
}
%>
</tbody>
</table>
</BODY>
</HTML>
并未進行持久化, 如有需要, 可以定時儲存到資料庫。
隻需要在儲存之後清空本地的值即可。
一般情況下, 統計通路次數等功能, 不需要考慮極端情況, 隻要不影響系統的性能即可。
然後通路相應的位址:
傳回的JSON 如下所示:
{"clientIp":"61.50.103.90","visitCount":4}
時間: 2018年2月9日
作者: 鐵錨