使用Spring-Context的注解实现依赖注入功能.
Demo要点：
本例子中主要使用Annotation功能来实现对MoviceService的注入。我们将Cinema.java的头部标注为@Component说明该类交由Spring托管。而Cinema.java中的属性MoviceService标注为@Autowired，则Spring在初始化Cinema类时会从Application Context中找到类型为MovieService的Bean，并赋值给Cinema。在Application.java中我们声明了一个类型为MovieService的Bean。并且标注Application.java为@Configuration,这是告诉Spring在Application.java中定义了一个或多个@Bean方法，让Spring容器可以在运行时生成这些Bean。@ComponentScan则会让Spring容器自动扫描当前package下的标有@Component的class，这些class都将由Spring托管。此时 就要注意Application.java需要在一个较为上层的包，不然会报错找不到类。
项目结构：
Pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >
<modelVersion>4.0.0</modelVersion>
<groupId>MarkDemo</groupId>
<artifactId>MarkDemo.SpringContext</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build /> <dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.1.RELEASE</version>
</dependency>
</dependencies> </project>
MovieService.java
package MarkDemo.service;
public interface MovieService {
String getMovieName();
}
DefaultMovieService.java
package MarkDemo.service;
public class DefaultMovieService implements MovieService {
public String getMovieName() {
return "INTO THE WILD, HELLO SPRING CONTEXT";
}
}
Cinema.java
package MarkDemo.service; import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component; @Component
public class Cinema { @Autowired
private MovieService movieService; public void printMovieName() {
System.out.println(movieService.getMovieName());
} public MovieService getMovieService() {
return movieService;
} public void setMovieService(MovieService movieService) {
this.movieService = movieService;
} }
Application.java
package MarkDemo.service; import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration; @Configuration
@ComponentScan
public class Application { @Bean
public MovieService getMovieService() {
return new DefaultMovieService();
} public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(Application.class);
Cinema cinema = applicationContext.getBean(Cinema.class);
cinema.printMovieName();
applicationContext.close(); } }
没有annotation支持之前则需要applicationContext.xml文件。
<?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"
xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <bean id="movieService" class="MarkDemo.service.DefaultMovieService"></bean> <bean id="cinema" class="MarkDemo.service.Cinema">
<property name="movieService" ref="movieService"></property>
</bean> </beans>
application.java的main方法
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(Application.class);
Cinema cinema = applicationContext.getBean(Cinema.class);
cinema.printMovieName();
applicationContext.close();
//不使用annotation，使用配置文件。
System.out.println(ClassLoader.getSystemResource(""));
@SuppressWarnings("resource")
ApplicationContext appContext= new ClassPathXmlApplicationContext("classpath:/MarkDemo/service/applicationContext.xml");
Cinema cinema1=appContext.getBean("cinema",MarkDemo.service.Cinema.class);
cinema1.printMovieName();
}
参考文章：http://www.2cto.com/kf/201403/284656.html