一、项目案例(xml)
- 非Spring接管下的三层项目构建:
- Spring接管下的三层项目构建:
二、项目案例(注解)
- 改进配置文件

一、项目案例(xml)

使用三层架构进行用户的插入操作.
界面层, 业务逻辑层, 数据访问层(模拟).

Spring会接管三层架构中哪些对象的创建?界面层的对象,业务逻辑层的对象,数据访问层的对象.

非Spring接管下的三层项目构建:
实体类
com.bjpowernode.pojo Users
数据访问层
com.bjpowernode.dao UsersMapper.java(接口)
UsersMapperImpl.java(实现类)
业务逻辑层
com.bjpowernode.service UsersService.java(接口)
UsersServiceImpl.java(实现类 )
界面层
com.bjpowernode.controller UsersController.java

非Spring接管下的三层项目构建:

Spring项目案例 - 图1
pojo包

public class Users {
    private int uid;
    private String uname;
    private int uage;
    public int getUid() {
        return uid;
    }

dao包(模拟)

public interface UsersMappr {
    //增加用户
    int insert(Users u );
}

public class UsersMapperImpl implements UsersMappr {
    @Override
    public int insert(Users u) {
        System.out.println(u.getUname()+"用户增加成功!");
        return 1;
    }
}

service包下

public interface UsersService {
    //增加用户
    int insert(Users users);
}

/**
 *  业务逻辑层的实现类
 */
public class UsersServiceImpl implements UsersService {
    //切记切记:在所有的业务逻辑层中都必定有数据访问层的对象
    private UsersMappr usersMappr = new UsersMapperImpl();
    @Override
    public int insert(Users users) {
        //添加更复杂的业务,但是我们现在没有复杂业务
        return usersMappr.insert(users);
    }
}

controller包

/**
 *  界面层
 */
public class UsersController {
    //如何去访问业务逻辑层,就是创建对象
    //切记切记:所有的界面层都会有业务逻辑层的对象
    public UsersService usersService = new UsersServiceImpl();
    //界面层的功能实现,对外提供访问的功能
    public int insert(Users users){
        return usersService.insert(users);
    }
}

Test包

public class MyTest {
    @Test
    public void testInsertUsers(){
        //?创建谁的对象  创建UsersController对象
        UsersController usersController = new UsersController();
        int  num = usersController.insert(new Users(100,"张三",22));
        System.out.println(num);
    }
}

Spring接管下的三层项目构建:

YEG`%(385(6XZ42GAM7TBYM.png
pojo包

public class Users {
    private int uid;
    private String uname;
    private int uage;
    //set()  get() tpString()
}

resources

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
  <!--创建各种对象-->
  <!--创建数据访问层的对象-->
  <bean id="uMapper" class="com.bjpowernode.dao.UsersMapperImpl">
  </bean>
  <!--创建业务逻辑层-->
  <bean id="uService" class="com.bjpowernode.service.impl.UsersServiceImpl">
    <property name="usersMappr" ref="uMapper"></property>
  </bean>
  <!--创建界面层对象-->
  <bean id="uController" class="com.bjpowernode.controller.UsersController">
    <property name="usersService" ref="uService"></property>
  </bean>
</beans>

dao包

public interface UsersMappr {
    //增加用户
    int insert(Users u );
}

/**
 *  数据访问层的实现类
 */
public class UsersMapperImpl implements UsersMappr {
    @Override
    public int insert(Users u) {
        System.out.println(u.getUname()+"用户增加成功!");
        return 1;
    }
}

service包

public interface UsersService {
    //增加用户
    int insert(Users users);
}

/**
 *  业务逻辑层的实现类
 */
public class UsersServiceImpl implements UsersService {
    //切记切记:在所有的业务逻辑层中都必定有数据访问层的对象
    private UsersMappr usersMappr; //= new UsersMapperImpl();
    //交给Spring去依赖注入值,必须提供setXXX()方法
    public void setUsersMappr(UsersMappr usersMappr) {
        this.usersMappr = usersMappr;
    }
    @Override
    public int insert(Users users) {
        //添加更复杂的业务,但是我们现在没有复杂业务
        return usersMappr.insert(users);
    }
}

controller包

/**
 *  界面层
 */
public class UsersController {
    //如何去访问业务逻辑层,就是创建对象
    //切记切记:所有的界面层都会有业务逻辑层的对象
    public UsersService usersService;// = new UsersServiceImpl();
    //交给Spring去注入值，必须提供setXXX()方法
    public void setUsersService(UsersService usersService) {
        this.usersService = usersService;
    }
    //界面层的功能实现,对外提供访问的功能
    public int insert(Users users){
        return usersService.insert(users);
    }
}

test包

public class MyTest {
    @Test
    public void testInsertUsers(){
        //创建容器并启动
        ApplicationContext ac =new ClassPathXmlApplicationContext("applicationContext.xml");
        //取出对象
        UsersController usersController =(UsersController) ac.getBean("uController");
        //测试功能
        int num=usersController.insert(new Users(200,"王五",24));
        System.out.println(num);
    }
}

二、项目案例(注解)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--只要是基于注解开发，必须扫描-->
    <context:component-scan base-package="com.bjpowernode"></context:component-scan>
</beans>

public class Users {
    private int uid;
    private String uname;
    private int uage;
    //set() get() toString
}

dao包

public interface UsersMappr {
    //增加用户
    int insert(Users u );
}

/**
 *  数据访问层的实现类
 */
@Repository  //就是交给spring框架去创建数据访问层的对象
public class UsersMapperImpl implements UsersMappr {
    @Override
    public int insert(Users u) {
        System.out.println(u.getUname()+"用户增加成功!");
        return 1;
    }
}

service包

public interface UsersService {
    //增加用户
    int insert(Users users);
}

/**
 *  业务逻辑层的实现类
 */
@Service  //交给spring创建业务逻辑层的对象
public class UsersServiceImpl implements UsersService {
    //切记切记:在所有的业务逻辑层中都必定有数据访问层的对象
    @Autowired
    private UsersMappr usersMappr;// = new UsersMapperImpl();
    @Override
    public int insert(Users users) {
        //添加更复杂的业务,但是我们现在没有复杂业务
        return usersMappr.insert(users);
    }
}

controller包

/**
 *  界面层
 */
@Controller  //交给Spring去创建对象
public class UsersController {
    //如何去访问业务逻辑层,就是创建对象
    //切记切记:所有的界面层都会有业务逻辑层的对象
    @Autowired
    public UsersService usersService ;  //= new UsersServiceImpl();
    //界成层的功能实现,对外提供访问的功能
    public int insert(Users users){
        return usersService.insert(users);
    }
}

测试类

package com.bjpowernode.test;
import com.bjpowernode.controller.UsersController;
import com.bjpowernode.pojo.Users;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 *
 */
public class MyTest {
    @Test
    public void testInsertUsers(){
       //创建并启动容器
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        //取出UsersController对象
        UsersController usersController = (UsersController) ac.getBean("usersController");
        usersController.insert(new Users(100,"haha",25));
    }
}

改进配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--批量导入其它配置文件-->
    <import resource="applicationContext_*.xml"></import>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--只要是基于注解的开发,必须包扫描-->
    <context:component-scan base-package="com.bjpowernode.dao"></context:component-scan>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--只要是基于注解的开发,必须包扫描-->
    <context:component-scan base-package="com.bjpowernode.service"></context:component-scan>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <!--只要是基于注解的开发,必须包扫描-->
    <context:component-scan base-package="com.bjpowernode.controller"></context:component-scan>
</beans>