Java - 根据IP获取城市

• ip2region

准确率99.9%的ip地址定位库，0.0x毫秒级查询，数据库文件大小只有1.5M，提供了java,php,c,python,nodejs,golang查询绑定和Binary,B树,内存三种查询算法

github地址：https://github.com/lionsoul2014/ip2region

• 下载v1.3版本：https://github.com/lionsoul2014/ip2region/releases/tag/v1.3-release

解压目录如下图：

• 新建java项目，导入binding/java下的代码，并复制”data/ip2region.db”到“src目录

创建“IPUtil”.java ,内容参考”org.lionsoul.ip2region.test.TestSearcher.java“

 1 package com.xx;
 2  
 3 import java.io.File;
 4 import java.lang.reflect.Method;
 5  
 6 import org.lionsoul.ip2region.DataBlock;
 7 import org.lionsoul.ip2region.DbConfig;
 8 import org.lionsoul.ip2region.DbSearcher;
 9 import org.lionsoul.ip2region.Util;
10  
11 public class IPUtil {
12  
13     public static String getCityInfo(String ip){
14  
15         //db
16         String dbPath = IPUtil.class.getResource("/ip2region.db").getPath();
17  
18         File file = new File(dbPath);
19         if ( file.exists() == false ) {
20             System.out.println("Error: Invalid ip2region.db file");
21         }
22  
23         //查询算法
24         int algorithm = DbSearcher.BTREE_ALGORITHM; //B-tree
25                         //DbSearcher.BINARY_ALGORITHM //Binary
26                         //DbSearcher.MEMORY_ALGORITYM //Memory
27         try {
28             DbConfig config = new DbConfig();
29             DbSearcher searcher = new DbSearcher(config, dbPath);
30  
31             //define the method
32             Method method = null;
33             switch ( algorithm )
34             {
35             case DbSearcher.BTREE_ALGORITHM:
36                 method = searcher.getClass().getMethod("btreeSearch", String.class);
37                 break;
38             case DbSearcher.BINARY_ALGORITHM:
39                 method = searcher.getClass().getMethod("binarySearch", String.class);
40                 break;
41             case DbSearcher.MEMORY_ALGORITYM:
42                 method = searcher.getClass().getMethod("memorySearch", String.class);
43                 break;
44             }
45  
46             DataBlock dataBlock = null;
47             if ( Util.isIpAddress(ip) == false ) {
48                 System.out.println("Error: Invalid ip address");
49             }
50  
51             dataBlock  = (DataBlock) method.invoke(searcher, ip);
52  
53             return dataBlock.getRegion();
54  
55         } catch (Exception e) {
56             e.printStackTrace();
57         }
58  
59         return null;
60     }
61  
62  
63     public static void main(String[] args)  throws Exception{
64         System.err.println(getCityInfo("220.248.12.158"));
65     }
66 }

转自：https://www.cnblogs.com/face-ghost-coder/p/8867855.html