Get the different elements of the two list

Get the different elements of the two list

/**  *  several different methods, different query efficiency  *getdiffrent5 () highest efficiency  */  import  java.util.arraylist;  import java.util.hashmap;  import java.util.list;   import java.util.Map;    /**  *  gets the different objects in the two list collection   */   public class test2listdiff {        public  static void main (String[] args)  {           List<String> list1 = new ArrayList<String> ();           List<String> list2 = new ArrayList< String> ();          int num = 5;           // int num=5000;            for (int i = 0; i < num; i++)  {               list1.add ("Test_"  + i);               list2.add ("Test_"  + i * 2);           }             getdiffrent3 (LIST1,&NBSP;LIST2);          &NBSP;GETDIFFRENT5 (LIST1,&NBSP;LIST2);           getdiffrent4 (LIST1,&NBSP;LIST2);           getdiffrent2 (List1, list2 );           getdiffrent (LIST1,&NBSP;LIST2);             // getDiffrent3 total times  32271699           // getdiffrent5 total times 12239545            // getDiffrent4 total times  16786491           // getdiffrent2 total  times 2438731459       }         /**      *  get different elements of the two list       *        *  @param  list1      * @ param list2      *  @return       */  &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;PRIVATE&NBSP;STATIC&NBSP;LIST&LT;STRING&GT;&NBSP;GETDIFFRENT5 (List<String> &NBSP;LIST1,&NBSP;LIST&LT;STRING&GT;&NBSP;LIST2)  {           long st =&nbSp System.nanotime ();           list<string> diff  = new ArrayList<String> ();           list<string> maxlist = list1;           list<string> minlist = list2;           if  (List2.size ()  > list1.size ())  {               maxList = list2;               minList = list1;           }            //  save data from list to map            map<string, integer> maxmap  = new  Hashmap<string, integer> (Maxlist.size ());           for  (string string : maxlist)  {               maxmap.put (string, 1);           }            // max :1,2,3,4,5           // min:2,4,6,8,10              //  loop values in Minlist, marking in  maxmap   The same   data 2           for  (String string  : minlist)  {               //  the same                if   (Maxmap.get (String)  !=&nbsP;null)  {                   maxmap.put (string, 2);                   continue;               }               //  Unequal                 Diff.add (String);          }           printf (diff);             //  Circulating maxmap           for  (Map.Entry <string, integer> entry : maxmap.entryset ())  {               if  (Entry.getvalue ()  == 1)  {                   diff.add (Entry.getKey ());               }           }          printf (diff);             system.out.println ("getDiffrent5 total  times  " +  (System.nanotime ()  - st));           return diff;      }         /**      *  get two different elements of the list       *        *  @param  list1      *  @param  list2      *  @return       */       private static list<string> getdiffrent4 (list<string> list1, list &LT;STRING&GT;&NBSP;LIST2)  {          long st  = system.nanotime ();           map<string,  Integer> map = new HashMap<String, Integer> (List1.size ()  +  List2.size ());           list<string> diff =  new ArrayList<String> ();          list< string> maxlist = list1;          list< string> minlist = list2;          if  (List2.size ()  > List1.size ())  {               maxlist = list2;               minlist = list1;          }           for  (string string : maxlist)  {               map.put (string, 1);           }           for  (string string : minlist)  {               integer cc = map.get (String);               if  (cc != null)  {         &Nbsp;         map.put (STRING,&NBSP;++CC);                   continue;               }               map.put (string, 1);           }          for  (map.entry< String, integer> entry : map.entryset ())  {               if  (Entry.getvalue ()  == 1)  {                   diff.add ( Entry.getkey ());              }       &nbsP;   }          system.out.println (" getdiffrent4 total times  " +  (System.nanotime ()  - st));           return diff;      }         /**      *  get two different elements of the list        *       *  @param  list1       *  @param  list2      *  @return        */      private static List<String>  GetDiffrent3 (LIST&LT;STRING&GT;&NBSP;LIST1,&NBSP;LIST&LT;STRING&GT;&NBSP;LIST2)  {           long st = system.nanotime ();           map<String, Integer> map = new HashMap<String, Integer> (List1.size ()  + list2.size ());          list<string>  diff = new ArrayList<String> ();           for  (String string : list1)  {               map.put (string, 1);           }          for  (string string &NBSP;:&NBSP;LIST2)  {               Integer cc = map.get (String);               if  (cc != null)  {                   map.put (STRING,&NBSP;++CC);                   continue;               }               map.put (string, 1);          }           for  (map.entry<string, integer>  Entry : map.entryset ())  {               if  (Entry.getvalue ()  == 1)  {                   diff.add (Entry.getkey ());               }           }  &nBsp;       system.out.println ("getdiffrent3 total times "  +  (System.nanotime ()  - st));           return diff;      }        /**       *  get different elements of a list       *        *  @param  list1      *  @param   list2      *  @return       */       private static list<string> getdiffrent2 (List<String>  LIST1,&NBSP;LIST&LT;STRING&GT;&NBSP;LIST2)  {           Long st = system.nanotime ();           List1.retainall (LIST2);   &nbSp;       system.out.println ("getdiffrent2 total times "  +  (System.nanotime ()  - st));           return list1;      }        /**       *  get two different elements of the list       *        *  @param  list1      *  @param   list2      *  @return       */       private static list<string> getdiffrent (List<String>  LIST1,&NBSP;LIST&LT;STRING&GT;&NBSP;LIST2)  {           Long st = system.nanotime ();           list <string> diff =&nbsP;new arraylist<string> ();          for  ( STRING&NBSP;STR&NBSP;:&NBSP;LIST1)  {               if  (!list2.contains (str))  {                   diff.add (str);               }          }           system.out.println ("Getdiffrent total times    +  (System.nanotime ()  - st);           return diff;      }         public static void printf (list<string> list)  {          &nbsp System.out.println ("----------------------------");           for  (Int i = 0; i < list.size ();  i++)  {               system.out.println (List.get (i));           }      }

Get different elements of the two list