手拉手入门Spring6之Ioc注解开发

组件，控制器，业务、仓库
控制器，业务、仓库都是组件的别名

@Component
@Controller
@Service
@Repository

pomxml加入aop的依赖

 <!-- 引入Spring context依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>6.0.0-M2</version>
        </dependency>

SpringConfig.xml主配置文件

xmlns:context="http://www.springframework.org/schema/context"

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

Bean类上使用注解
value是默认的

组件扫描
<!--        组件扫描-->
        <context:component-scan base-package="com.spring.bean"></context:component-scan>
<!--组件扫描多个包-->
<!--        <context:component-scan base-package="com.spring.bean,com.spring.web"></context:component-scan>-->
<!--        <context:component-scan base-package="com.spring"></context:component-scan>-->

测试类
@Test
    public void  AnnotationDemo(){
        ApplicationContext applicationContext =new ClassPathXmlApplicationContext("SpringConfig.xml");
        Object studentBean = applicationContext.getBean("StudentBean");
        Object userBean = applicationContext.getBean("userBean");
        Object orderBean = applicationContext.getBean("OrderBean");
        Object teacherBean = applicationContext.getBean("TeacherBean");
        System.out.println(studentBean);
        System.out.println(userBean);
        System.out.println(orderBean);
        System.out.println(teacherBean);
    }

<!--    第一种 use-default-filters="false"如果是false表示这个包下所有带有声明的注解全部失效
<context:component-scan base-package="com.Bean" use-default-filters="false"/>
        
-->
    <context:component-scan base-package="com.Bean" use-default-filters="false">
                                                <!-- 想让那个注解生效就选择那个       只有生效Component -->
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Component"/>
    </context:component-scan>

<!--    第二种：
use-default-filters="ture" 所有带有注解的全部生效,不写use-default-filters，则默认为true
-->
    <context:component-scan base-package="com.Bean" use-default-filters="true">
        <!-- 排除谁不生效 （谁不生效）除了Controller不生效，其他都生效-->
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

SpringConfig.xml配置

<?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-->
        <context:component-scan base-package="com.spring.bean"></context:component-scan>
</beans>

//当属性是简单数据类型的时候，可以使用@Value注解进行注入
@Value是用来代替<property name="name" value="张三"/>

public class Student {
    @Value("张三")
    private String name;
    @Value("20")
    private int age;
--get、set、toString--
}

@Autowired可以用来注入非简单类型。单独使用@Autowired注解：默认根据类型装配。[默认byType]
@Autowired可以出现在构造方法，方法，参数，属性，别的注解上。

public interface StudentDao {
    void insert();
}

@Repository("StudentDaoImpl")
public class StudentDaoImpl implements StudentDao{
    @Override
    public void insert() {
        System.out.println("StudentDaoImpl");
    }
}

@Service("StudentService")
public class StudentService {
    @Autowired
    StudentDao studentDao;
    public void test(){
        studentDao.insert();
    }
}

//测试类
@Test
public void AnnotationInto(){
    ApplicationContext applicationContext =new ClassPathXmlApplicationContext("SpringConfig.xml");
    StudentService studentService = applicationContext.getBean("StudentService", StudentService.class);
    studentService.test();
}

//当有多个实现类对象时，@Autowired和Qualifier联合使用，可以根据名称进行装配
//Qualifier可以指定要执行的实现类对象

public interface StudentDao {
    void insert();
}

@Repository("StudentDaoImpl")
public class StudentDaoImpl implements StudentDao{
    @Override
    public void insert() {
        System.out.println("StudentDaoImpl");
    }
}

@Repository("StudentDaoImpl2")
public class StudentDaoImpl2 implements StudentDao{
    @Override
    public void insert() {
        System.out.println("StudentDaoImpl2");
    }
}

//无法自动匹配。“studentdao”类型的bean不止一个。由此可见@Autowired不能在多个相同类型的Bean对象中使用。

@Service("StudentService")
public class StudentService {
    @Autowired
    @Qualifier("StudentDaoImpl2")
    StudentDao studentDao;
    public void test(){
        studentDao.insert();
    }
}

//测试
@Test
public void AnnotationInto(){
    ApplicationContext applicationContext =new ClassPathXmlApplicationContext("SpringConfig.xml");
    StudentService studentService = applicationContext.getBean("StudentService", StudentService.class);
    studentService.test();
}

@Resource注解是JDK扩展包中的，属于JDK的一部分。该注解是标准注解，更加具有通用性。(JSR-250标准中指定的注解类型。JSR是Java规范提案)
@Autowired注解是Spring框架的。
@Resource注解默认根据名称装配byName，未指定name时，使用属性名作为name。通过name找不到的话会自动启动通过类型byType装配。
@Autowired注解默认根据类型装配byType，@Autowired想根据名称装配，需要配合@Qualifier注解一起用。

@Resource注解可以用在属性上，set方法上。
@Autowired注解可以用在属性上，set方法上，构造方法上，构造方法参数上。

@Resource注解是JDK扩展包，不在JDK当中，需要引入依赖。
Spring6不在支持JavaEE,它支持的是JakartaEE9。
Spring6使用这个依赖

Spring6使用这个依赖
        <dependency>
            <groupId>jakarta.annotation</groupId>
            <artifactId>jakarta.annotation-api</artifactId>
            <version>2.1.0</version>
        </dependency>

Spring5使用这个依赖
        <dependency>
            <groupId>jakarta.annotation</groupId>
            <artifactId>jakarta.annotation-api</artifactId>
            <version>1.3.2</version>
        </dependency>

public interface StudentDao {
    void insert();
}

@Repository("StudentDaoImpl")
public class StudentDaoImpl implements StudentDao{
    @Override
    public void insert() {
        System.out.println("StudentDaoImpl");
    }
}

@Repository("StudentDaoImpl2")
public class StudentDaoImpl2 implements StudentDao{
    @Override
    public void insert() {
        System.out.println("StudentDaoImpl2");
    }
}

@Service("StudentService")
public class StudentService {
    //@Autowired
    //@Qualifier("StudentDaoImpl2")
    @Resource(name ="StudentDaoImpl2")
    StudentDao studentDao;
    public void test(){
        studentDao.insert();
    }
}

//测试
@Test
public void AnnotationInto(){
    ApplicationContext applicationContext =new ClassPathXmlApplicationContext("SpringConfig.xml");
    StudentService studentService = applicationContext.getBean("StudentService", StudentService.class);
    studentService.test();
}

//创建一个类来代替SpringConfig.xml

@Configuration
//组件扫描
@ComponentScan({"com.spring.bean","com.spring.Dao"})
public class SpringConfig {
}

//测试

 @Test
    public void AnnotationInto(){
        ApplicationContext applicationContext =new AnnotationConfigApplicationContext(SpringConfig.class);
        StudentService studentService = applicationContext.getBean("StudentService", StudentService.class);
        studentService.test();
    }