模仿struts:UserManager(业务层)

package com.ankangqiao.servlet;import java.util.ArrayList;import java.util.List;public class UserManager {public void addUser(String username) {System.out.println(username + " 添加用户成功");}public void deleteUser(String username) {System.out.println(username + " 已删除");}public void modifyUser(String username) {System.out.println(username + " 已修改");}public List queryUser(String username) {System.out.println(username + " 已查询");List users = new ArrayList();users.add("a");users.add("b");users.add("c");return users;}}