#集合的常用操作类CollectionUtils

// 并集  
Collection<String> unionList = CollectionUtils.union(aList, bList);  
// 交集  
Collection<String> intersectionList = CollectionUtils.intersection(aList, bList);  
// 是否存在交集  
boolean isContained = CollectionUtils.containsAny(aList, bList);  
// 交集的补集  
Collection<String> disjunctionList = CollectionUtils.disjunction(aList, bList);  
// 集合相减  
Collection<String> subtractList = CollectionUtils.subtract(aList, bList);  
  
// 排序  
Collections.sort((List<String>) unionList);  
Collections.sort((List<String>) intersectionList);  
Collections.sort((List<String>) disjunctionList);  
Collections.sort((List<String>) subtractList);