阅读所有可能的角色，或硬code列表。然后迭代它运行的isUserInRole并建立角色的用户是在一个列表中，然后将列表转换为一个阵列

Read in all the possible roles, or hardcode a list. Then iterate over it running the isUserInRole and build a list of roles the user is in and then convert the list to an array.

String[] allRoles = {"1","2","3"};
HttpServletRequest request = ... (or from method argument)
List userRoles = new ArrayList(allRoles.length);
for(String role : allRoles) {
 if(request.isUserInRole(role)) { 
  userRoles.add(role);
 }
}

// I forgot the exact syntax for list.toArray so this is prob wrong here
return userRoles.toArray(String[].class);