diff --git a/海亮定制.md b/海亮定制.md
index c9a7c73..f97a05c 100644
--- a/海亮定制.md
+++ b/海亮定制.md
@@ -491,7 +491,7 @@ String content = "hex:" + bytesToHexString(title.getBytes("GBK"))
 public static String bytesToHexString(byte[] src) {
     StringBuilder stringBuilder = new StringBuilder("");
     if (src == null || src.length <= 0) {
-        return null;
+        return "";
     }
     for (int i = 0; i < src.length; i++) {
         int v = src[i] & 0xFF;
@@ -892,7 +892,7 @@ public static String bytesToHexString(byte[] src) {
  public static String bytesToHexString(byte[] src) {
 	StringBuilder stringBuilder = new StringBuilder("");
 	if (src == null || src.length <= 0) {
-		return null;
+		return "";
 	}
 	for (int i = 0; i < src.length; i++) {
 		int v = src[i] & 0xFF;