老师编写的读取propertites文件的类

package cn.qdqn.tool;
import java.io.IOException;
import java.util.Properties;
public class MyConfigTool {
private static Properties prop;
public synchronized static String getProperty(String key) {
if (null == prop) {
prop = new Properties();
try {
prop.load(Thread.currentThread().getContextClassLoader()
.getResourceAsStream("config/config.properties"));
} catch (IOException e) {
e.printStackTrace();
System.out.println("config/config.properties 加载失败 !");
}
}
return prop.getProperty(key);
}
}