求交差集

String s1 = "50000,100000,200000,30000000,50000000,";   
        String s2 = "10000,30000,50000,100000,";   
        String[] a1 = s1.split(",");   
        String[] a2 = s2.split(",");   
        List list = new ArrayList(Arrays.asList(a1));   
      //  list.retainAll(Arrays.asList(a2)); // list 中的就是交集了   
	   list.removeAll(Arrays.asList(a2)); // list 中的就是差集了   
        for(int i = 0;i < list.size(); i++){   
            System.out.println("----" + list.get(i));   
        }