Spring学习总结5(IOC-基于注解Annotation)

要使用Annotation，需确认Spring的版本是2.0以上，JDK版本是5.0以上

使用注解的XML的配置

<?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-2.5.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-2.5.xsd">

<!-- 指明Spring容器使用注解的方式初始化bean -->

<context:annotation-config/>

</beans>

@Autowired

按类型去查找并注入

使用范围：

1.setter方法

public class SimpleMovieLister {

private MovieFinder movieFinder;

@Autowired

public void setMovieFinder(MovieFinder movieFinder) {

this.movieFinder = movieFinder;

}

// ...

}

2.以成员变量(bean)为参数的方法

public class MovieRecommender {

private MovieCatalog movieCatalog;

private CustomerPreferenceDao customerPreferenceDao;

@Autowired

public void prepare(MovieCatalog movieCatalog, CustomerPreferenceDao customerPreferenceDao) {

this.movieCatalog = movieCatalog;

this.customerPreferenceDao = customerPreferenceDao;

}

// ...

}

3.构造方法或成员变量

public class MovieRecommender {

@Autowired

private MovieCatalog movieCatalog;

private CustomerPreferenceDao customerPreferenceDao;

@Autowired

public MovieRecommender(CustomerPreferenceDao customerPreferenceDao) {

this.customerPreferenceDao = customerPreferenceDao;

}

// ...

}

@Autowired(required=false) 当查找失败时不会报错，默认不写时为required=true

@Qualifier

按名字去查找并注入

1.使用在成员变量上

public class MovieRecommender {

@Autowired

@Qualifier("mainCatalog")

private MovieCatalog movieCatalog;

// ...

}

2.使用在方法参数bean上

public class MovieRecommender {

private MovieCatalog movieCatalog;

private CustomerPreferenceDao customerPreferenceDao;

@Autowired

public void prepare(@Qualifier("mainCatalog") MovieCatalog movieCatalog, CustomerPreferenceDao customerPreferenceDao) {

this.movieCatalog = movieCatalog;

this.customerPreferenceDao = customerPreferenceDao;

}

// ...

}

@Resource

按name值进行查找   @Resource有一个‘name’属性，缺省时，Spring 将这个值解释为要注射的 bean 的名字

public class SimpleMovieLister {

private MovieFinder movieFinder;

@Resource(name="myMovieFinder")

public void setMovieFinder(MovieFinder movieFinder) {

this.movieFinder = movieFinder;

}

}

// 在容器中查找名字为myMovieFinder的bean

public class SimpleMovieLister {

private MovieFinder movieFinder;

@Resource

public void setMovieFinder(MovieFinder movieFinder) {

this.movieFinder = movieFinder;

}

}

// 在容器中查找名字为movieFinder的bean

@Component

是所有受Spring管理组件的通用形式。

@Repository(存储层)、@Service(服务层)和 @Controller(控制层)则是@Component的细化， 用来表示更具体的用例(例如，分别对应了持久化层、服务层和表现层)。也就是说， 你能用@Component来注解你的组件类， 但如果用@Repository、@Service 或@Controller来注解它们，你的类也许能更好地被工具处理，或与切面进行关联。

加上该注解的bean，就不用在xml中进行bean的定义了。

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-2.5.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-2.5.xsd">

<context:component-scan base-package="org.example"/>

</beans>

使用@Component注解需要在xml配置自动扫描范围。同时Spring也提供了在扫描范围内进行过滤的配置。

过滤器类型	表达式范例
annotation	org.example.SomeAnnotation
assignable	org.example.SomeClass
regex	org/.example/.Default.*
aspectj	org.example..*Service+

<context:component-scan base-package="org.example">

<!-- 配置包含过滤 -->

<context:include-filter type="regex" expression=".*Stub.*Repository"/>

<!-- 配置排除过滤 -->

<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/>

</context:component-scan>

// 注册名字为myMovieLister，类型为SimpleMovieLister,生命周期为prototype的bean

@Component("myMovieLister")

@Scope("prototype")

public class SimpleMovieLister {

// ...

}

// 注册名字为movieFinderImpl ，类型为SimpleMovieLister的bean (默认bean名字为类名且首字母小写，生命周期为singleton)

@Component

public class MovieFinderImpl implements MovieFinder {

// ...

}

@PostConstruct

表明该方法在bean初始化时首先执行

@PostConstruct

public void init() {

System.out.println("init");

}

@PreDestroy

表明该方法在bean生命周期结束时执行

@PreDestroy

public void destroy() {

System.out.println("destroy");

}