java - 是什么导致了这个 Java "Cannot find symbol"错误？

Question

我正在修改继承的代码并不断收到奇怪的“找不到符号”错误，这让我很不爽。

   //======= Error =========

Compiling 1 source file to /Users/Inprimus/Projects/Workspace/Soft/build/web/WEB-INF/classes
/Users/Inprimus/Projects/Workspace/Soft/WebContent/WEB-INF/classes/fr/service/CarPeer.java:49: cannot find symbol
symbol : method addCarToCompany(java.lang.Long,fr.model.company.Car)
location: class fr.dao.CompanyDAO
cmpDAO.addCarToCompany(idCompany,car);
^
1 error

汽车同行:

package fr.service;    
import fr.model.company.Car;
import fr.dao.CompanyDAO;
import fr.dao.CarDao;

public class CarPeer {
    private static CarDao carDAO= new CarDao();
    private static CompanyDAO cmpDAO = new CompanyDAO();

    public static void storeCar(Long idCompany, Car car) throws UserServiceException, Exception {
        try {
            cmpDAO.addCarToCompany(idCompany,car);
            System.out.println("Car stored : "+car.toString()+" in "+idCompany);
            carDAO.storeCar(car);
        } catch(DAOException ex) {
            throw new UserServiceException(ex.getMessage(), ex);
        }
    }
}

公司道:

   package fr.dao;
    import fr.model.accounting.Cost;
    import fr.model.company.Car;

    public class CompanyDAO extends GenericDAO<Company> {

    private enum ChildType {
    COST{
    public void addChildToCompany(Company company, Object child) {
    company.addCost((Cost)child);
    }
    },
    CAR{
    public void addChildToCompany(Company company, Object child) {
    company.addCar((Car)child);
    }
    };
    public abstract void addChildToCompany(Company company, Object child);
    }
private void addChildToCompany(Long idCompany, Object child, ChildType type) throws NotFoundDAOException, AlreadyExistDAOException, Exception {
        try {
            // Begin unit of work
            Session session = HibernateUtil.getSessionFactory().getCurrentSession();
            session.beginTransaction();

            Company company = (Company) session.load(Company.class, idCompany);

            type.addChildToCompany(company, child);
            session.flush();

            // End unit of work
            session.getTransaction().commit();

        } catch (ObjectNotFoundException ex) {
            HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().rollback();
            throw new NotFoundDAOException("Identified object " + idCompany
                    + " doesn't exist in database", ex);
        } catch (ConstraintViolationException ex) {
            HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().rollback();
            throw new AlreadyExistDAOException("The new identity already exsits in database", ex);
        } catch (Exception ex) {
            ex.printStackTrace();
            HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().rollback();
            throw new Exception(ex);
        }
    }
    public CompanyDAO() {
    super(Company.class);
    }
    public void addCarToCompany(Long idCompany, Car car) throws NotFoundDAOException, AlreadyExistDAOException, Exception {
    addChildToCompany(idCompany, car, ChildType.CAR);
    }
    }

我已经进行了三重检查，但到目前为止没有发现代码有任何问题。我正在 Netbeans 7.0.1 中构建它。我应该提到我在构建时遇到了这个错误，但我可以毫无问题地运行 Web 应用程序(目前)。但我担心这可能会反过来咬人。

---

我刚刚在文件树中注意到，在 CompanyDAO 类上方是类似命名的文件，格式如下:CompanyDAO$ChildType#.class(# 对应于一个数字)我猜它没有重新编译该类生成我添加的额外子类型。我怎样才能做到这一点？

Answer 1

很可能您在您的类路径中使用了一个以前编译的类文件(它没有方法)，而系统正在尝试使用它而不是您当前的源代码。

否则，请清理您的工作区，不要依赖现有的编译并重试。这在我过去发生过。