一、PropertyPlaceholderHelper 职责
扮演者占位符解析器的角色,专门用来负责解析路劲中or名字中的占位符的字符，并替换上具体的值
二、例子
public class PropertyPlaceholderHelperDemo {
@SuppressWarnings("resource")
public static void main(String[] args) {
Properties properties = System.getProperties();
properties.setProperty("prefixName", "read-code");
ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:${prefixName}-spring.xml");
ReadCodeService readCodeService = (ReadCodeService) ac.getBean("readCodeService");
readCodeService.say();
}
}
你可以debug进去，看下源码。底层PropertyPlaceholderHelper会去解析替换占位符value。