基于注解的DI容器配置元数据

一、定义POJO类

package test;/** * IHelloStr接口 * * @author zxs */public interface IHelloStr { public String getContent(); }

 

package test;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import java.util.Properties;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;/** * 基于文件形式，读取HelloWorld所需的字符串。 * * @author zxs */public class FileHelloStrImpl implements IHelloStr { protected static final Log log = LogFactory.getLog(FileHelloStrImpl.class); private String propfilename; public FileHelloStrImpl(String propfilename) { this.propfilename = propfilename; } public String getContent() { String helloworld = ""; try { Properties properties = new Properties(); //读入输入流 InputStream is = getClass().getClassLoader().getResourceAsStream( propfilename); properties.load(is); is.close(); //获得helloworld键对应的取值 helloworld = properties.getProperty("helloworld"); } catch (FileNotFoundException ex) { log.error(ex); } catch (IOException ex) { log.error(ex); } return helloworld; } }

 

package test;/** * IHelloWorld接口 * * @author zxs * */public interface IHelloWorld {public abstract String getContent();}

 

package test;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;public class HelloWorld implements IHelloWorld { protected static final Log log = LogFactory.getLog(HelloWorld.class); private IHelloStr helloStr; public void setHelloStr(IHelloStr str) {this.helloStr = str;} public String getContent() { return helloStr.getContent(); } }

 

二、将上述两个POJO配置于类中,构造IoC容器

package test;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.springframework.config.java.annotation.Bean;import org.springframework.config.java.annotation.Configuration;import org.springframework.config.java.context.JavaConfigApplicationContext;@Configurationpublic class JavaConfigDemo {protected static final Log log = LogFactory.getLog(JavaConfigDemo.class);@Beanpublic IHelloWorld helloWorld(){HelloWorld hw = new HelloWorld();hw.setHelloStr(helloStr());return hw;}@Beanpublic IHelloStr helloStr(){return new FileHelloStrImpl("helloworld.properties");}public static void main(String[] args) {//从注解中装载DI容器配置元数据JavaConfigApplicationContext context = new JavaConfigApplicationContext(JavaConfigDemo.class);//获得受管BeanIHelloWorld hw = context.getBean(IHelloWorld.class);//返回字符串log.info(hw.getContent());}}