方式一:

@Test
    public void test10() {
        int[] my_array = {1, 2, 5, 5, 6, 6, 7, 2, 9, 2, 2};
        int count=0;
        for(int j=0;j<my_array.length;j++) {
            for(int k =j+1;k<my_array.length;k++) {
                if(my_array[j]==my_array[k]) {
                    count++;
                }
            }
            if(count==1){
                System.out.println( "重复元素 : " +  my_array[j] );
            }

            count = 0;
        }
    }

方式二:

@Test
    public void test10() {
        int[] my_array = {1, 2, 5, 5, 6, 6, 7, 2, 9, 2, 2};
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int num : my_array) {
            if (map.containsKey(num)){
                map.put(num,map.get(num) + 1);
            }else {
                map.put(num,1);
            }
        }

        Iterator<Map.Entry<Integer, Integer>> iterator = map.entrySet().iterator();
        while (iterator.hasNext()){
            Map.Entry<Integer, Integer> entry = iterator.next();
            if (entry.getValue() > 1)
            System.out.println("重复元素 : " + entry.getKey());
        }
    }