示例：
属性文件：beans.properties
articleDao=cn.com.leadfar.cms.backend.dao.impl.ArticleDaoImpl
channelDao=cn.com.leadfar.cms.backend.dao.impl.ChannelDaoImpl
使用此属性时类的配置如下：
PropertiesBeanFactory.java
package cn.com.leadfar.cms.utils;
import java.io.IOException;
import java.util.Properties;
import cn.com.leadfar.cms.backend.dao.ArticleDao;
import cn.com.leadfar.cms.backend.dao.ChannelDao;
public class PropertiesBeanFactory implements BeanFactory {
Properties props = new Properties();
public PropertiesBeanFactory(){
//读取配置文件，得到具体DAO的实现类名
try {
props.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("beans.properties"));
} catch (IOException e) {
e.printStackTrace();
}
}
public ArticleDao getArticleDao() {
String className = props.getProperty("articleDao");
try {
Class clz = Class.forName(className);
return (ArticleDao)clz.newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
public ChannelDao getChannelDao() {
String className = props.getProperty("channelDao");
try {
Class clz = Class.forName(className);
return (ChannelDao)clz.newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
}
