java获取properties中的参数

//定义一个常量类
public class ZFBConfig {
    public static String URL;                            //网关地址
    public static String APP_ID;                         //支付宝分配给开发者的应用ID
    public static String APP_PRIVATE_KEY;                //商户私钥
    public static String ALIPAY_PUBLIC_KEY;              //支付宝公钥


    static {
       //
        Properties p = DemoUtil.loadPropertyFromClasspath("properties/alipay.properties");
        URL = p.getProperty("URL");
        APP_ID = p.getProperty("APP_ID");
        APP_PRIVATE_KEY = p.getProperty("APP_PRIVATE_KEY");
        ALIPAY_PUBLIC_KEY = p.getProperty("ALIPAY_PUBLIC_KEY");
    }
}

public class DemoUtil {

//参数为properties的路径

public static Properties loadPropertyFromClasspath(String config) {
   Properties p = new Properties();
   InputStream is = null;
   try {
      is = DemoUtil.class.getClassLoader().getResourceAsStream(config);
      p.load(is);
   } catch (IOException e) {
      e.printStackTrace();
   } finally {
      if(is != null) {
         try {
            is.close();
         } catch (IOException e) {
            e.printStackTrace();
         }
      }
   }

   return p;
}

}