Java 手动配置某一范围内IP访问

说明
很多的Web系统都经常有这样的需求以保证系统安全，限制IP登录，例如在某个局域网中只允许一定范围内IP登录系统，或者不允许外网访问。
如只允许192.168.24.10---192.168.24.255范围内IP地址访问
IP地址分类
在说到关于IP地址的问题时，首先，要了解IP分类，IP一般分为A、B、C、D、E五类，我们常说的192.168.*.*，是属于C类，该类主要适用于小型网络，比如我们学校的局域网。
IP地址范围从192.168.0.0到192.168.255.255，不包括这两个地址，他们属于保留地址。
限制示例
这个实例写在了Struts的Action方法里面，当然也可以拿出来，写在Filter里，这样可以通过简单配置就可以实现禁止客户端访问。
LoginAction

package com.bjpowernode.drp.web.actions; 
 
import java.util.Arrays; 
 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
 
import org.apache.struts.action.Action; 
import org.apache.struts.action.ActionForm; 
import org.apache.struts.action.ActionForward; 
import org.apache.struts.action.ActionMapping; 
 
import com.bjpowernode.drp.web.forms.LoginActionForm; 
 
/**
 * 登录Action
 * 负责取得表单数据、调用业务逻辑、返回转向信息
 * 
 * @author Administrator
 *
 */ 
public class LoginAction extends Action { 
 
    @Override 
    public ActionForward execute(ActionMapping mapping, ActionForm form, 
            HttpServletRequest request, HttpServletResponse response) 
            throws Exception { 
        //取得表单数据  
        LoginActionForm laf=(LoginActionForm)form; 
        //取得用户名，密码  
        String username=laf.getUsername(); 
        String password=laf.getPassword(); 
        //转向对象  
        ActionForward actionForward=null; 
        //判断用户名，密码是否正确  
        if ("admin".equals(username) && "admin".equals(password)) { 
            //得到远程客户端IP地址   
            String remoteAddr=request.getRemoteAddr(); 
            //将客户端IP地址以“.”分割为数组remoteAddrs[1]);  
            String[]  remoteAddrs=remoteAddr.split("\\.");  
 
            //从配置文件中取得IP范围 ,四个数组分别保存的IP地址四部分的上界和下界   
            String[] ipOne=request.getSession().getServletContext().getInitParameter("ip-one").split(","); 
            String[] ipTwo=request.getSession().getServletContext().getInitParameter("ip-two").split(","); 
            String[] ipThree=request.getSession().getServletContext().getInitParameter("ip-three").split(","); 
            String[] ipFour=request.getSession().getServletContext().getInitParameter("ip-four").split(","); 
            //取得第四部分的上下界   
            int m=Integer.parseInt(ipFour[0]); 
            int n=Integer.parseInt(ipFour[1]); 
            //判断客户端IP地址是否在设置范围内  
            if (ipOne[0].equals(remoteAddrs[0]) && ipTwo[0].equals(remoteAddrs[1]) && ipThree[0].equals(remoteAddrs[2])) { 
                for(int i=m;i<=n;i++) { 
                    if (Integer.parseInt(remoteAddrs[3])==i) { 
                        //登录成功    
                        request.getSession().setAttribute("user", username); 
                        actionForward= mapping.findForward("success"); 
                    }  
                }  
                actionForward= mapping.findForward("ipError"); 
            }  
        }else {  
            //登录失败  
            actionForward= mapping.findForward("index"); 
        } 
        return actionForward; 
    }   
  
} 

package com.bjpowernode.drp.web.actions;

import java.util.Arrays;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import com.bjpowernode.drp.web.forms.LoginActionForm;

/**
 * 登录Action
 * 负责取得表单数据、调用业务逻辑、返回转向信息
 *
 * @author Administrator
 *
 */
public class LoginAction extends Action {

 @Override
 public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response)
   throws Exception {
  //取得表单数据
  LoginActionForm laf=(LoginActionForm)form;
  //取得用户名，密码
  String username=laf.getUsername();
  String password=laf.getPassword();
  //转向对象
  ActionForward actionForward=null;
  //判断用户名，密码是否正确
  if ("admin".equals(username) && "admin".equals(password)) {
   //得到远程客户端IP地址
   String remoteAddr=request.getRemoteAddr();
   //将客户端IP地址以“.”分割为数组remoteAddrs[1]);
   String[]  remoteAddrs=remoteAddr.split("\\.");

   //从配置文件中取得IP范围 ,四个数组分别保存的IP地址四部分的上界和下界
   String[] ipOne=request.getSession().getServletContext().getInitParameter("ip-one").split(",");
   String[] ipTwo=request.getSession().getServletContext().getInitParameter("ip-two").split(",");
   String[] ipThree=request.getSession().getServletContext().getInitParameter("ip-three").split(",");
   String[] ipFour=request.getSession().getServletContext().getInitParameter("ip-four").split(",");
   //取得第四部分的上下界
   int m=Integer.parseInt(ipFour[0]);
   int n=Integer.parseInt(ipFour[1]);
   //判断客户端IP地址是否在设置范围内
   if (ipOne[0].equals(remoteAddrs[0]) && ipTwo[0].equals(remoteAddrs[1]) && ipThree[0].equals(remoteAddrs[2])) {
    for(int i=m;i<=n;i++) {
     if (Integer.parseInt(remoteAddrs[3])==i) {
      //登录成功 
      request.getSession().setAttribute("user", username);
      actionForward= mapping.findForward("success");
     }
    }
    actionForward= mapping.findForward("ipError");
   }
  }else {
   //登录失败
   actionForward= mapping.findForward("index");
  }
  return actionForward;
 } 
 
}

Web.xml配置

<?xml version="1.0" encoding="UTF-8"?> 
<web-app version="2.4"  
    xmlns="http://java.sun.com/xml/ns/j2ee"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 
   <!-- 例如我的ip地址为192.168.24.165，并不在设置范围内；下标范围是192.168.24.1-164 --> 
   <context-param> 
    <param-name>ip-one</param-name> 
    <param-value>192</param-value> 
  </context-param> 
  <context-param> 
    <param-name>ip-two</param-name> 
    <param-value>168</param-value> 
  </context-param> 
  <context-param> 
    <param-name>ip-three</param-name> 
    <param-value>24</param-value> 
  </context-param> 
  <context-param> 
    <param-name>ip-four</param-name> 
    <param-value>1,164</param-value> 
  </context-param>  
   
</web-app> 

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
 xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
   <!-- 例如我的ip地址为192.168.24.165，并不在设置范围内；下标范围是192.168.24.1-164 -->
   <context-param>
   <param-name>ip-one</param-name>
   <param-value>192</param-value>
  </context-param>
  <context-param>
   <param-name>ip-two</param-name>
   <param-value>168</param-value>
  </context-param>
  <context-param>
   <param-name>ip-three</par补充：软件开发 , Java ,