String s1 = "50000,100000,200000,300000,500000,";
String s2 = "10000,30000,50000,100000,";
String[] a1 = s1.split(",");
String[] a2 = s2.split(",");
List<String> list = new ArrayList(Arrays.asList(a1));
list.retainAll(Arrays.asList(a2)); // list 中的就是交集了
for(String s : list){
System.out.println(s);
}