//找出集合中重复和不重复元素List<String> list6 = new ArrayList<>();Collections.addAll(list6, "a","a", "a", "e", "c", "w", "e", "c", "2");System.out.println(list6);Set<String> list7 = new HashSet<>();Set<String> list8 = new HashSet<>();for (int i = 0; i < list6.size(); i++) {//如果集合中不包含list6集合的每一项走if判断if(!list7.contains(list6.get(i))){list7.add(list6.get(i));//这是去重后的}//如果集合包含list6集合的每一项走else判断else{list8.add(list6.get(i));//这是所有重复元素}}System.out.println("去重后的："+list7);//去重后的结果System.out.println("list6中重复的元素："+list8);//list6中有重复元素的结果//不重复元素for (int i = 0; i < list6.size(); i++) {//list8是所有重复的元素，如果不包含list6集合的每一项，剩下的就是不重复的元素了if(!list8.contains(list6.get(i))){System.out.println("list6中不重复的元素："+list6.get(i));//这是不重复的元素 ，list6中没有重复的元素结果}}
//找出重复的元素List list4 = new ArrayList();Collections.addAll(list4, "a","a", "a", "e", "c", "w", "e", "c", "2");System.out.println(list4);Set list5 = new HashSet();for (int i = 0; i < list4.size(); i++) {for (int j = i+1; j < list4.size(); j++) {if (list4.get(j).equals(list4.get(i))) {list5.add(list4.get(i));//把相同元素加入list(找出相同的)}}}System.out.println(list5);//不重复元素for (int i = 0; i < list4.size(); i++) {if(!list5.contains(list4.get(i))){System.out.println(list4.get(i));}}System.out.println("----------------------------");//查找不重复元素ArrayList<String> strings = new ArrayList<>();Collections.addAll(strings,"1","1","2","2","3","4");//先跟自己比较一次肯定是+1的，然后再去做对比有相同的++每相同的con就=1了for (int i = 0; i < strings.size(); i++) {int con = 0;for (int j = 0; j < strings.size(); j++) {if(strings.get(i).equals(strings.get(j))){con++;}}if(con==1){System.out.println(strings.get(i));}}
