feats

src/main/java/com/yunzhi/niucai/alipay/Utils.java

 import java.nio.file.Paths;
 
 public class Utils {
+    /**
+     * 小文件读取, 文件大小不能超过 2M
+     * @param f
+     * @return
+     * @throws IOException
+     */
     public static String readFile(String f) throws IOException {
         FileChannel file = FileChannel.open(Paths.get(f));
         int fileSize = (int) file.size();