高效的找出两个List中的不同元素

/*
* TestList.java
* Version 1.0.0
* Created on 2017年12月15日
* Copyright ReYo.Cn
*/
package reyo.sdk.utils.test.list2;

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);
		}
		getDiffrent(list1, list2);
		getDiffrent3(list1, list2);
		getDiffrent5(list1, list2);
		getDiffrent4(list1, list2);
		getDiffrent2(list1, list2);

		//        getDiffrent3 total times 32271699
		//        getDiffrent5 total times 12239545
		//        getDiffrent4 total times 16786491
		//        getDiffrent2 total times 2438731459

	}

	/**
	 * 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;

	}

	/**
	 * 获取两个List的不同元素
	 * @param list1
	 * @param list2
	 * @return
	 */
	private static List<String> getDiffrent4(List<String> list1, List<String> 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) {
				map.put(string, ++cc);
				continue;
			}
			map.put(string, 1);
		}
		for (Map.Entry<String, Integer> entry : map.entrySet()) {
			if (entry.getValue() == 1) {
				diff.add(entry.getKey());
			}
		}
		System.out.println("getDiffrent4 total times " + (System.nanoTime() - st));
		return diff;

	}

	/**
	 * 获取两个List的不同元素
	 * @param list1
	 * @param list2
	 * @return
	 */
	private static List<String> getDiffrent3(List<String> list1, List<String> 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 : list2) {
			Integer cc = map.get(string);
			if (cc != null) {
				map.put(string, ++cc);
				continue;
			}
			map.put(string, 1);
		}
		for (Map.Entry<String, Integer> entry : map.entrySet()) {
			if (entry.getValue() == 1) {
				diff.add(entry.getKey());
			}
		}
		System.out.println("getDiffrent3 total times " + (System.nanoTime() - st));
		return diff;
	}

	/**
	 * 获取连个List的不同元素
	 * @param list1
	 * @param list2
	 * @return
	 */
	private static List<String> getDiffrent2(List<String> list1, List<String> list2) {
		long st = System.nanoTime();
		list1.retainAll(list2);
		System.out.println("getDiffrent2 total times " + (System.nanoTime() - st));
		return list1;
	}

	/**
	 * 获取两个List的不同元素
	 * @param list1
	 * @param list2
	 * @return
	 */
	private static List<String> getDiffrent(List<String> list1, List<String> list2) {
		long st = System.nanoTime();
		List<String> diff = new ArrayList<String>();
		for (String str : list1) {
			if (!list2.contains(str)) {
				diff.add(str);
			}
		}
		System.out.println("getDiffrent total times " + (System.nanoTime() - st));
		return diff;
	}
}

 getDiffrent total times 320118400
getDiffrent3 total times 12051500
getDiffrent5 total times 6301100
getDiffrent4 total times 7527300
getDiffrent2 total times 298880900