spring的三层架构

分层架构:

面向对象编程-->JavaBean-->Book

和数据库交互

jdbc、hibernate、mybatis(持久化机制)

DAO层专门负责数据库交互 CRUD(增查改删)

Service层 对于一些业务判断处理，

eg:添加图书-->西游记 后传 西游记续

图书名称判断(通过书名进行查询)

public boolean checkBookName(String bookName){

Book book = bookDao.getBookByName(bookName);

if(book != null){

return true;

}

return false;

}

Controller:接收用户请求 和页面交互

(跟页面交互-->直接和用户交互)

private Book book;

private IBookService bookService;

public String add(){

String name = book.getBookName();

boolean isExists = bookService.checkBookName(name);

if(isExists){

//

}else{

//允许添加

}

}

例子：

Controller --> Service --> Dao

框架设计

model

class Book{}

dao

interface IBookDao{}

@Repository

class BookDao implements IBookDao{}

service

interface IBookService{}

@Service

class BookService implements IBookService{

@Autowired

private IBookDao bookDao;

}

controller

@Controller

class BookController{

@Autowired

private IBookService bookService;

}