今天在运用spring的PropertyPlaceholderConfigurer时发现一个有意思的内容，当你在applicationContext中配置一个PropertyPlaceholderConfigurer的bean时，有location和locations的属性，不明思意location对应一个.properties文件，
locations对应多个.properties文件，冲着想看一下PropertyPlaceholderConfigurer的实现机制，于是查看了spring的源码，发现在PropertyPlaceholderConfigurer中并没有location和locations的属性，于是一路向上在父类PropertiesLoaderSupport中找到了locations的属性，但是没有location属性，奇怪？但在PropertiesLoaderSupport中却有setLocation和setLocations两个方法：
/**
* Set a location of a properties file to be loaded.
* <p>Can point to a classic properties file or to an XML file
* that follows JDK 1.5's properties XML format.
*/
public void setLocation(Resource location) {
this.locations = new Resource[] {location};
}
/**
* Set locations of properties files to be loaded.
* <p>Can point to classic properties files or to XML files
* that follow JDK 1.5's properties XML format.
*/
public void setLocations(Resource[] locations) {
this.locations = locations;
}
这样看来applicationContext.xml中的bean的property的name属性的值，并不是和对应类类中的属性内容是一致的
