Use the binary search to determine the IP region range test, ip Region
All IP addresses are converted to the Long type. Each region is represented by an IP segment and the IP segment is determined by a binary search.
Package hello;
Import java. util .*;
Public class datatest {
Public static void main (String [] args) throws InterruptedException {
Final HashMap <Integer, String> map = new HashMap <Integer, String> ();
Final String DELIMITER = "\ t ";
String line = ("1677721616777471 Australia ");
String [] str = line. split (DELIMITER );
Integer key_begin = Integer. parseInt (str [0]. trim ());
Integer key_end = Integer. parseInt (str [1]. trim ());
String country = str [2]. trim ();
// System. out. println (key_begin + "" + "" + country );
Map. put (key_begin, country );
ArrayList <Integer> list = new ArrayList <Integer> ();
Integer ip = 16777473;
List. add (1, 16777216 );
List. add (1, 16777472 );
List. add (1, 16778240 );
List. add (1, 16779264 );
List. add (1, 16777471 );
List. add (1, 16778239 );
List. add (1, 16779263 );
List. add (1, 16781311 );
Collections. sort (list );
System. out. println (list. toString ());
// [16777216,167 77471, 16777472,167 78239, 16778240,167 79263, 16779264,167 81311]
Int low = 0;
Int high = list. size ();
Int middle;
Int value;
While (low <= high ){
Middle = (low + high)/2;
Value = list. get (middle );
System. out. println ("middle =" + middle + "and value =" + value );
Thread. sleep (300 );
If (ip <list. get (middle )){
High = middle-1;
} Else if (ip> list. get (middle )){
Low = middle + 1;
System. out. println (high + "" + low );
Thread. sleep (300 );
}
} System. out. println (high + "" + list. get (high ));
}
}
