public class BaseServlet extends HttpServlet {
protected CompanyService companyService;
protected DeptService deptService;
protected UserService userService;

@Override
public void init() throws ServletException {
companyService = new CompanyServiceImpl();
deptService = new DeptServiceImpl();
userService = new UserServiceImpl();
}
创建对象的抽取,init()方法,便于后期进行维护,减少缓存,占用,减少new的次数