6.装配Bean基于注解

1.注解：就是一个类，使用@注解名称

开发中：使用注解取代 xml配置文件。

@Component取代<bean class="">

@Component("id") 取代 <bean id="" class="">

2.web开发，提供3个@Component注解衍生注解（功能一样）取代<bean class="">

@Repository ：dao层

@Service：service层

@Controller：web层

3.依赖注入，给私有字段设置，也可以给setter方法设置

普通值：@Value("")

引用值：

方式1：按照【类型】注入

@Autowired

方式2：按照【名称】注入1

@Autowired

@Qualifier("名称")

方式3：按照【名称】注入2
@Resource("名称")

4.生命周期

初始化：@PostConstruct

销毁：@PreDestroy

5.作用域

@Scope("prototype") 多例

注解使用前提，添加命名空间，让spring扫描含有注解类

例子一:

beans.xml

<?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

                              http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 组件扫描，扫描含有注解的类 -->

    <context:component-scan base-package="com.jd.annotation.ioc"></context:component-scan>

</beans>

UserService.java

package com.jd.annotation.ioc;

/**

 * @author weihu

 * @date 2018/8/14/014 0:16

 */

public interface UserService {

    void addUser();

}

UserServiceImpl.java

package com.jd.annotation.ioc;

import org.springframework.stereotype.Component;

/**

 * @author weihu

 * @date 2018/8/14/014 0:16

 *

 * @Component("id") 取代 <bean id="" class="">

 */

@Component("userServiceId")

public class UserServiceImpl implements UserService {

    @Override

    public void addUser() {

        System.out.println("添加用户成功!");

    }

}

TestAnnoIoC.java

package com.jd.annotation.ioc;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**

 * @author weihu

 * @date 2018/8/14/014 0:19

 */

public class TestAnnoIoC {

    @Test

    public void testAnnotitaion(){

        String xmlPath="com/jd/annotation/ioc/beans.xml";

        ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);

        UserService userService = (UserService) applicationContext.getBean("userServiceId");

        userService.addUser();

    }

}

例子二:

beans.xml

<?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

                              http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 组件扫描，扫描含有注解的类 -->

    <context:component-scan base-package="com.jd.annotation.web"></context:component-scan>

</beans>

StudentAction.java

package com.jd.annotation.web;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

/**

 * @author weihu

 * @date 2018/8/14/014 0:25 controller层

 */

@Controller("studentActionId")

public class StudentAction {

    @Autowired  //默认按照类型

    private StudentService studentService;

    public void execute(){

        studentService.addStudent();

    }

}

StudentDao.java

package com.jd.annotation.web;

/**

 * @author weihu

 * @date 2018/8/14/014 0:28

 */

public interface StudentDao {

    void save();

}

StudentDaoImpl.java

package com.jd.annotation.web;

import org.springframework.stereotype.Repository;

/**

 * @author weihu

 * @date 2018/8/14/014 0:29

 *

 * Repository ：dao层

 */

@Repository("studentDaoId")

public class StudentDaoImpl implements StudentDao{

    @Override

    public void save() {

        System.out.println("save dao");

    }

}

StudentService.java

package com.jd.annotation.web;

/**

 * @author weihu

 * @date 2018/8/14/014 0:26

 */

public interface StudentService {

    void addStudent();

}

StudentServiceImpl.java

package com.jd.annotation.web;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.beans.factory.annotation.Qualifier;

import org.springframework.stereotype.Service;

/**

 * @author weihu

 * @date 2018/8/14/014 0:27 service层

 */

@Service

public class StudentServiceImpl implements StudentService {

    private StudentDao studentDao;

    @Autowired

    @Qualifier("studentDaoId")

    public void setStudentDao(StudentDao studentDao) {

        this.studentDao = studentDao;

    }

    @Override

    public void addStudent() {

        studentDao.save();

    }

}

TestAnnoWeb.java

package com.jd.annotation.web;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**

 * @author weihu

 * @date 2018/8/14/014 0:44

 */

public class TestAnnoWeb {

    @Test

    public void testAnnotion(){

        String xmlPath="com/jd/annotation/web/beans.xml";

        ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);

        StudentAction studentAction = applicationContext.getBean("studentActionId", StudentAction.class);

        studentAction.execute();

    }

}

例子三:

beans.xml

<?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

                              http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 组件扫描，扫描含有注解的类 -->

    <context:component-scan base-package="com.jd.annotation.other"></context:component-scan>

</beans>

UserService.java

package com.jd.annotation.other;

public interface UserService {

    public void addUser();

}

UserServiceImpl.java

package com.jd.annotation.other;

import javax.annotation.PostConstruct;

import javax.annotation.PreDestroy;

import org.springframework.context.annotation.Scope;

import org.springframework.stereotype.Service;

@Service("userServiceId")

//@Scope("prototype")

public class UserServiceImpl implements UserService {

    @Override

    public void addUser() {

        System.out.println("d_scope add user");

    }

    @PostConstruct

    public void myInit(){

        System.out.println("初始化");

    }

    @PreDestroy

    public void myDestroy(){

        System.out.println("销毁");

    }

}

TestOther.java

package com.jd.annotation.other;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestOther {

    @Test

    public void testBeforeAndAfter(){

        //spring 工厂

        String xmlPath = "com/jd/annotation/other/beans.xml";

        ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);

        UserService userService = applicationContext.getBean("userServiceId" ,UserService.class);

        UserService userService2 = applicationContext.getBean("userServiceId" ,UserService.class);

        System.out.println(userService);

        System.out.println(userService2);

        applicationContext.close();

    }

}

巴特西

6.装配Bean基于注解

最新文章

热门文章