package io.guangsoft.analysis;

 /*

      数据文件:

     1.1.1.0/24,123

     1.1.2.0/28,345

     1.2.0.0/16,789

  */

 public interface Finder {

     //完成初始化动作

     boolean loadFile(String fileName);

     //查找具体IP所在IP网段的键值，未找到返回-1；比如如果输入样例数据文件，调用find("1,1,1,1"),返回123

     int find(String ipStr);

 }

 package io.guangsoft.analysis;

 import java.io.BufferedReader;

 import java.io.File;

 import java.io.FileReader;

 import java.util.HashMap;

 import java.util.Map;

 import org.apache.commons.net.util.SubnetUtils;

 import org.apache.commons.net.util.SubnetUtils.SubnetInfo;

 public class FinderImpl implements Finder {

     private Map<String, String> dataMap = new HashMap<String, String>();

     @Override

     public boolean loadFile(String fileName) {

         File file = new File(this.getClass().getClassLoader().getResource(fileName).getFile());

         try {

             FileReader fileReader = new FileReader(file);

             BufferedReader bufferedReader = new BufferedReader(fileReader);

             while(true) {

                 String nextLine = bufferedReader.readLine();

                 if(nextLine == null) {

                     break;

                 } else {

                     String str[] = nextLine.split(",");

                     dataMap.put(str[0], str[1]);

                 }

             }

         } catch (Exception e) {

             e.printStackTrace();

             return false;

         }

         return true;

     }

     @Override

     public int find(String ip) {

         for(String network : dataMap.keySet()) {

             boolean bingo = isInRange(ip, network);

             if(bingo) {

                 return Integer.parseInt(dataMap.get(network));

             }

         }

         return -1;

     }

     //核心代码，检索IP所属网段

     public boolean isInRange(String ip, String network) {

         String[] ips = ip.split("\\.");

         int ipAddr = (Integer.parseInt(ips[0]) << 24)

                 | (Integer.parseInt(ips[1]) << 16)

                 | (Integer.parseInt(ips[2]) << 8)

                 | Integer.parseInt(ips[3]);

         int type = Integer.parseInt(network.replaceAll(".*/", ""));

         int mask = 0xFFFFFFFF << (32 - type);

         String networkIp = network.replaceAll("/.*", "");

         String[] networkIps = networkIp.split("\\.");

         int networkIpAddr = (Integer.parseInt(networkIps[0]) << 24)

                 | (Integer.parseInt(networkIps[1]) << 16)

                 | (Integer.parseInt(networkIps[2]) << 8)

                 | Integer.parseInt(networkIps[3]);

          return (ipAddr & mask) == (networkIpAddr & mask);

     }

     //也可以使用apache的net工具类

     public boolean isInRange2(String ip, String network) {

         SubnetInfo subnetInfo = new SubnetUtils(network).getInfo();

         return subnetInfo.isInRange(ip);

     }

     public static void main(String args[]) {

         FinderImpl finder = new FinderImpl();

         if(finder.loadFile("data.txt")) {

             int num = finder.find("1.1.1.1");

             System.out.println(num);

         }

     }

 }