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Spring-DI-注解

2014-03-10 20:55 447 查看

注解

* 必须依赖于类中的某一个部分

* 注解应该在类的哪些部位出现

* 自定义注解

* 了解jdk内置的注解

* 解析注解

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
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-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> 
<context:annotation-config></context:annotation-config>
<bean id="student" class="cn.itcast.spring0909.di.annotation.Student"></bean>
<bean id="person" class="cn.itcast.spring0909.di.annotation.Person"></bean>
</beans>

/**
* 原理
*    *  启动spring容器，并且加载配置文件
*    *  会为student和person两个类创建对象
*    *  当解析到<context:annotation-config></context:annotation-config>
*       会启动依赖注入的注解解析器
*    *  会在纳入spring管理的bean的范围内查找看哪些bean的属性上有@Resource注解
*    *  如果@Resource注解的name属性的值为"",则会把注解所在的属性的名称和spring容器中bean的id进行匹配
*       如果匹配成功，则把id对应的对象赋值给该属性，如果匹配不成功，则按照类型进行匹配,如果再匹配不成功，则报错
*    *  如果@Resource注解的name属性的值不为"",会把name属性的值和spring容器中bean的id做匹配，如果匹配
*       成功，则赋值，如果匹配不成功 ，则直接报错
* 说明：
*    注解只能用于引用类型
* @author Administrator
*
*/
public class PersonTest extends SpringHelper{
static{
path = "cn/itcast/spring0909/di/annotation/applicationContext.xml";
}

@Test
public void test(){
ClassPathXmlApplicationContext applicationContext = (ClassPathXmlApplicationContext)context;
Person person = (Person)applicationContext.getBean("person");
person.say();
applicationContext.close();
}
}

package cn.itcast.spring0909.di.annotation;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;

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

public class Person {
//@Autowired//按照类型进行匹配
//@Qualifier("student")
@Resource(name="student")
private Student studen;

@Resource//    这行会报错（所以注解只能用于引用类型）
private Long pid;

public void say(){
this.studen.say();
}

@PostConstruct
public void init(){
System.out.println("init");

}

public Person() {
super();
this.pid=1L;
}

@PreDestroy
public void destroy(){
System.out.println("destroy");
}
}

package cn.itcast.spring0909.di.annotation;

public class Student {
public void say(){
System.out.println("student");
System.err.println("xxxxxxxx");
}
}

SCAN

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
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-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="cn.itcast.spring0909.scan"></context:component-scan>
</beans>

/**
* 原理
*   *  启动spring容器，加载配置文件
*   *  spring容器解析到
*         <context:component-scan base-package="cn.itcast.spring0909.scan"></context:component-scan>
*   *  spring容器会在指定的包及子包中查找类上是否有@Component
*   *  如果@Component注解没有写任何属性
*        @Component
*        public class Person{
*
*        }
*        ==
*        <bean id="person" class="..Person">
*      如果@Component("aa")
*        @Component
*        public class Person{
*
*        }
*        ==
*        <bean id="aa" class="..Person">
*    *  在纳入spring管理的bean的范围内查找@Resource注解
*    *  执行@Resource注解的过程
*  说明：
*     xml效率比较高，但是书写比较麻烦
*     注解效率比较低，书写比较简单
* @author Administrator
*
*/
public class PersonTest extends SpringHelper{
static{
path = "cn/itcast/spring0909/scan/applicationContext.xml";
}
@Test
public void test(){
Person person = (Person)context.getBean("perso");
person.say();
}
}

@Component("perso")//加上这个注解 就可以让di容器自动扫描了
public class Person {
@Resource(name="student")
private Student studen;

private Long pid;

public void say(){
this.studen.say();
}

@PostConstruct
public void init(){
System.out.println("init");
}

@PreDestroy
public void destroy(){
System.out.println("destroy");
}
}

@Component
public class Student {
public void say(){
System.out.println("student");
}
}

mvc注解

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
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-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="cn.itcast.spring0909.mvc.spring.annotation">
</context:component-scan>
</beans>

/**
* 如果一个类中有基本类型，并且基本类型是用spring的形式赋值的，这个时候，该类必须用xml来完成，不能用注解
* @author Administrator
*
*/
@Controller("personAction")
public class PersonAction {
@Resource
private PersonService personService;

public void savePerson(){
this.personService.savePerson();
}
}

public interface PersonDao {
public void savePerson();
}

@Repository("personDao")
public class PersonDaoImpl implements PersonDao{
@Override
public void savePerson() {
// TODO Auto-generated method stub
System.out.println("save person");
}

}

public interface PersonService {
public void savePerson();
}

@Service
public class PersonServiceImpl implements PersonService{
@Resource(name="personDao")
private PersonDao personDao;

@Override
public void savePerson() {
// TODO Auto-generated method stub
this.personDao.savePerson();
}
}

public class PersonTest extends SpringHelper{
static{
path = "cn/itcast/spring0909/mvc/spring/annotation/applicationContext.xml";
}

@Test
public void test(){
PersonAction personAction = (PersonAction)context.getBean("personAction");
personAction.savePerson();
}
}

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