查找两个List集合中的不同元素

package com.czp.test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TestList {

    public static void main(String[] args) {
        List<String> list1 = new ArrayList<String>();
        List<String> list2 = new ArrayList<String>();
        for (int i = 0; i < 10000; i++) {
            list1.add("test"+i);
            list2.add("test"+i*2);
        }

        getDiffrent5(list1,list2);



//        getDiffrent5 total times 12239545

    }
    /**
     * 获取两个List的不同元素
     * @param list1
     * @param list2
     * @return
     */
    private static List<String> getDiffrent5(List<String> list1, List<String> list2) {
        long st = 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;
         }
         Map<String,Integer> map = new HashMap<String,Integer>(maxList.size());
         for (String string : maxList) {
             map.put(string, 1);
         }
         for (String string : minList) {
             if(map.get(string)!=null)
             {
                 map.put(string, 2);
                 continue;
             }
             diff.add(string);
         }
         for(Map.Entry<String, Integer> entry:map.entrySet())
         {
             if(entry.getValue()==1)
             {
                 diff.add(entry.getKey());
             }
         }
        System.out.println("getDiffrent5 total times "+(System.nanoTime()-st));
        return diff;

    }