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(); } }
参考文章:http://www.2cto.com/kf/201403/284656.html
时间: 2024-10-20 16:23:45