代码片段 -- Java计算代码执行消耗时间

long l1 = System.currentTimeMillis(); Map<Integer, String> recipients = new HashMap<Integer, String>(); Integer groupId = taskInst.getGroupId(); Group group = groupManager.getGroupById(groupId); taskInst.setGroupName(group.getName()); List<UserGroup> userGroups = userGroupManager .getListByGroupId(groupId); for (UserGroup userGroup : userGroups) { User user = userManager.getUser(userGroup.getUserId()); recipients.put(user.getId(), user.getFullName()); } long l2 = System.currentTimeMillis(); System.out.println(l2 - l1);