java读取配置文件

（1）利用java.util.Properties读取属性文件
     properties属性文件config.properties：

business.class=spring.Business
writer.class=spring.FloppyWriter

InputStream is = this.getClass().getClassLoader().getResourceAsStream("config.properties");
Properties pro = new Properties();
pro.load(is);
String businessClass = properties.getProperty("business.class");
String writerClass = properties.getProperty("writer.class");