Spring-DI-注解

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"><!-- 1、导入命名空间 xmlns:context="http://www.springframework.org/schema/context" http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd 2、到入依赖注入的注解解析器 <context:annotation-config></context:annotation-config>3、把student和person导入进来 --><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";}@Testpublic 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();}@PostConstructpublic void init(){System.out.println("init");}public Person() {super();this.pid=1L;}@PreDestroypublic 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"><!-- 1、导入命名空间 xmlns:context="http://www.springframework.org/schema/context" http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd 2、启动类扫描的注解解析器3、启动依赖注入的注解解析器--><!-- component就是beanbase-package   会在base-package的值所在的包及子包下扫描所有的类 --><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";}@Testpublic 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();}@PostConstructpublic void init(){System.out.println("init");}@PreDestroypublic void destroy(){System.out.println("destroy");}}

@Componentpublic 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 {@Resourceprivate PersonService personService;public void savePerson(){this.personService.savePerson();}}

public interface PersonDao {public void savePerson();}

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

public interface PersonService {public void savePerson();}

@Servicepublic class PersonServiceImpl implements PersonService{@Resource(name="personDao")private PersonDao personDao;@Overridepublic void savePerson() {// TODO Auto-generated method stubthis.personDao.savePerson();}}

public class PersonTest extends SpringHelper{static{path = "cn/itcast/spring0909/mvc/spring/annotation/applicationContext.xml";}@Testpublic void test(){PersonAction personAction = (PersonAction)context.getBean("personAction");personAction.savePerson();}}