spring - service-dao 模式的最佳实践是什么？

Question

让我们考虑一个简单的用户插入操作。我做这项工作的 Spring 相关类是 UserController , UserService , UserServiceImpl , UserDAO , UserDAOImpl .

在 Controller 端我打电话 userService.insert(new User())并在 userService.insert()我调用的方法 userDAO.insert(user) .我认为这种模式存在方法重复。

有没有办法避免方法重复？可能是我的编码有问题。我等你的回复，经验...

预先感谢...

Answer 1

对于我的项目，我使用这些服务和 DAO 层。
我不知道这是否是最佳实践。

这是一个示例创建操作级别:

[View Layer]
  * Simple HTML form or AJAX request
      |
      | User submits create form. Browser sends POST data
      | to controller.
      |
[User Controller]
  * Authentication and authorization. @Security annotations can be for method security.
  * Controller tries to bind POST data to UserCreateForm. If can't Validation exception occurs.
  * Validates bind data according to validation annotations. @Required ...
      |
      | (UserCreateForm) is POJO class which has validation annotations.
      | It is similar but different from domain objects.
      |
[User Controller]
  * Logs errors via Logging API (logback, slf4j, log4j ...)
  * Copies form values from UserCreateForm to User domain object
  * Calls service methods.
  * Passes messages and model objects to desired view page.
      |
      | (User) is POJO class. called domain object, contains ORM annotations if using JPA
      | or hibernate. It is similar but different from form/command objects. It can be
      | generated automatically by tools (IDE, hibernate tools ...)
      |
[UserService & UserServiceImpl]
  * Calls multiple DAO methods in one transaction. If an error occurs. rolls back.
  * Contains business logic
  * Doesn't know the database technology.
      |
      | (User) domain object.
      |
[UserDAO & HibernateUserDAOImpl || JpaUserDAOImpl || OracleJdbcDAOImpl ...]
  * DAO layer knows the persistence technology
  * Operations are atomic